Oil spill

OIL SPILL
A DETAILED STUDY OF CAUSES AND
PREVENTION WITH SPECIAL EMPHASIS ON
EFFECT OF OCEANIC CONDITION ON SPILL
By Parth Suthar

Outline
PART – I
Environmental Outlook
1. Introduction
2. Oil spill causes
3. Adverse environmental effects
(i) Effects of oil spill on water
(ii) Effect of oil spill on land
4. Response actions
5. Spill assessment
6. In-Situ burning
7 Recovery techniques against oil spill
8. Response strategy for onshore spill
(i) Oil Spill Contingency Plan (OSCP)
(ii) Intermediate response strategy
9. Preparedness and its prevention
10. On Shore Oil spill recovery Techniques
(i) Soil removal
(ii) In-Place soil treatment
(iii) Landfill disposal
(iv) Thermal treatment
(v) Soil aeration
11. Exxon Valdez Spill case study

PART -II
[INDUSTRIAL OUTLOOK]
1.Common Industrial causes of spills
2.Offshore pipeline failure
i. Causes
ii. Effects
3. A study of Indian & Foreign Scenario
4.Estimation of spill volume
5. Mumbai: Offshore conditions
6. Gulf Of Mexico: Offshore condition
i. Ocean surface
ii. Wind model
iii. Wave model
I. Loop Currents
7. A comparison between Gulf Of Mexico & Mumbai
Offshore
8. Pipeline stance taken in Gulf Of Mexico
9. Pipeline protection techniques adopted in Gulf Of
Mexico
10. Conclusive remedy
11. References
LIST OF FIGURES

1.1 Effect of oil spill on sea otters
1.2 birds and mammals will die from hypothermia.
1.3 In-situ burning
1.4 Mechanism of Dispersant
PART-I

[ENVIRONMENTAL OUTLOOK]
Introduction
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine
areas, due to human activity, and is a form of pollution. The term is usually applied to marine oil
spills, where oil is released into the ocean or coastal waters, but spills may also occur on land. Oil
spills may be due to releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as
well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, heavier
fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.
Oil spills penetrate into the structure of the plumage of birds and the fur of mammals, reducing its
insulating ability, and making them more vulnerable to temperature fluctuations and much
less buoyant in the water. Cleanup and recovery from an oil spill is difficult and depends upon
many factors, including the type of oil spilled, the temperature of the water (affecting evaporation
and biodegradation), and the types of shorelines and beaches involved. Spills may take weeks,
months or even years to clean up.
Oil spills can have disastrous consequences for society; economically, environmentally, and
socially. As a result, oil spill accidents have initiated intense media attention and political uproar,
bringing many together in a political struggle concerning government response to oil spills and what
actions can best prevent them from happening. Despite substantial national and international policy
improvements on preventing oil spills adopted in recent decades, large oil spills keep occurring
 The quantity of oil spilled during accidents has ranged from a few hundred tons to several
hundred thousand tons
 Smaller spills have already proven to have a great impact on ecosystems,
 Oil spills at sea are generally much more damaging than those on land, since they can spread
for hundreds of nautical miles in a thin oil slick which can cover beaches with a thin coating
of oil. These can kill sea birds, mammals, shellfish and other organisms they coat.

Spill Causes
Oil spills into rivers, bays, and the ocean most often are caused by accidents involving tankers,
barges, pipelines, refineries, drilling rigs, and storage facilities.
Spills can be caused by: people making mistakes or being careless. equipment breaking down.
Oil Spills may happen for several reasons.
1. When oil tankers have equipment faults.
When oil tankers break down, it may get stuck on shallow land. When the tanker is attempted
to move out of shallow land, abrasion may cause a hole in the tanker that will lead to large
amounts of oil being released into the oceanic bodies. However, although this form of oil spill is
the most commonly known and has the highest media attention, only 2% of oil in water bodies
is a result of this action.
2. From nature and human activities on land.
The large majority of oil spilled is from natural seeps geological seeps from the ocean floor as
well as leaks that occur when products using petroleum or various forms of oil are used on land,
and the oil is washed off into water bodies.
3. Water Sports.
Other causes of oil spills are spills by petroleum users of released oil. This happens when
various water sports or water vehicles such as motorboats and jet skis leak fuel.
4. Drilling works carried out in sea.
When drilling works carried out in the sea, the oil and petroleum used for such activities are
released into the sea, thus causing an oil spill.

Environmental effects
 Spilled oil can affect animals and plants in twо ways:
1. Dirесt from the oil and
2. The response or clean-up process.
Effects of oil spill on water:
Effect of oil spill include
1. Marine life Degradation
2. Deterioration of fish industry
3. Deterioration of local industry
Effect of oil spill on land
Effect of oil spill include
1. Soil degradation
2. Ground water concern
3. Animals and Micro-organisms
 First of these is the environmental effect. The animal life that lives in the water or near the
shore are the ones most affected by the spill. In most cases, the oil simply chokes the
animals to death.
 There is no clear relationship between the amount of oil in the aquatic environment and the
likely impact on Biodiversity.
 A smaller spill at the wrong time/wrong season and in a sensitive environment may prove
much more harmful than a larger spill at another time of the year in another or even the
same environment.

 Oil penetrates into the structure of the plumage of birds and the fur of mammals, reducing
its insulating ability, and making them more vulnerable to temperature fluctuations and
much less buoyant in the water.
 Animals who rely on scent to find their babies or mothers cannot due to the strong scent of
the oil. This causes a baby to be rejected and abandoned, leaving the babies to starve and
eventually die.
 Oil can impair a bird's ability to fly, preventing it from escaping from predators.
 As they preen, birds may ingest the oil coating their feathers, irritating the digestive tract,
altering liver function, and causing kidney damage. Together with their diminished foraging
capacity, this can rapidly result in dehydration and metabolic imbalance.
 Some birds exposed to petroleum also experience changes in their hormonal balance,
including changes in their luteinizing protein. The majority of birds affected by oil spills die
from complications without human intervention.
1.1 Effect of oil spill on sea otters
 Some studies have suggested that less than one percent of oil-soaked birds survive, even
after cleaning although the survival rate can also exceed ninety percent, as in the case of the
Treasure oil spill.
 Heavily furred marine mammals exposed to oil spills are affected in similar ways. Oil coats
the fur of sea otters and seals, reducing its insulating effect, and leading to fluctuations
in body temperature and hypothermia.


 1.2 birds and mammals will die from hypothermia.
 Oil can also blind an animal, leaving it defenseless. The ingestion of oil causes dehydration
and impairs the digestive process. Animals can be poisoned, and may die from oil entering
the lungs or liver.
 There are three kinds of oil-consuming bacteria. Sulfate-reducing bacteria (SRB) and acid-
producing bacteria are anaerobic, while general aerobic bacteria (GAB) are aerobic. These
bacteria occur naturally and will act to remove oil from an ecosystem, and their biomass will
tend to replace other populations in the food chain.
Oil Spill Response Plan will provide information, notification procedures, guidance and pre-
defined guidelines for initial actions in the event of a discharge of oil into the environment.
 Initial Oil Spill Response Actions
Initial oil spill response action provide key initial response guidelines in one section near the front
of the plan to facilitate quick access and present it in the general order that it is required in a
response. this section is intended to provide information and guidelines on initial oil spill response
actions. These actions should be provided in the general sequence required during a response.
For Tier spills, the response is often completed within the first 24 hours, and no further guidance is
necessary. For moderate to major (Tier 2 or 3) spills, a Unified Command will normally be formed
to direct the response activities, utilizing the Oil Spill Response Plan for general guidance. Therefore,
it is less critical for detailed guidelines to be provided for the later stages of a response.

Initial Response Actions
Intial response actions provide guidelines for the actions to be taken immediately upon discovery of
a release, including a quick situation size-up and identification of actual or potential health and
safety hazards. Also include initial actions to be taken by the Qualified Individual if different than
the other initial actions.
Action Sequence and Strategy
Consider including a flow/decision Response Strategy Guide depicting the initial actions in a
prioritized sequence such as the example provided below. Also provide a check-list depicting
prioritized initial actions that facility personnel could utilize to ensure key initial response actions are
implemented or considered.
It include following point:
Alert facility personnel/sound alarms
 Secure sources of ignition
 Initiate source control actions (activate emergency shutdown, close blowout preventer,
turn valves, shut down pumps, shut down power)
 Identify product and estimate quantity or rate of oil released
 Determine number and severity of injuries and request on-site medical assistance
 Secure the spill area (exclusion zone)
 Activate facility Emergency or Spill Response Team
 Activate fire-fighting systems or resources if needed
 Conduct preliminary incident severity/potential assessment

A multi-tier oil spill response approach is recommended for offshore oil spill response
planning. The tier system allows maximum flexibility in developing response strategies and
Spill Management Team structure,
the tier definitions are largely dependent on the requirements of the regulatory oversight
agency and are based on scenarios, including a worst-case discharge.(WCD - to determine
the maximum flow rate for an offshore oil well in the event of an oil spill)
3-tier response planning structure is as follows
 Tier 1
 Tier 2
 Tier 3
Tier 1
Small local spills
 Minor spills, including incipient spills that are quickly controlled, contained and cleaned up
using local (onsite or immediately available) company/contractor owned equipment and
personnel resources.
 For offshore facilities, local resources could include those at the facility, on nearby support
vessels or at a designated shore support base or staging area.
 A Tier 1 spill would typically be resolved within a few hours or days.
 Tier 1 spills are the most mild, causing localized damage usually near the company's own
facilities.
 In most cases, this type of spill occurs as a result of the company's own activities.
Tier 2
Medium spills that may be local or at some distance from operational centers

 Moderate spills, controlled or uncontrolled, requiring activation of significant regional (e.g.,
Gulf of Mexico) oil spill response resources and all or most of the Spill Management Team.
 A Tier 2 spill response may continue for several days or weeks.
 This will cover company operations at their own facilities
 the physical area of the spill is larger than in the Tier 1 case.
Tier 3
Large spills which may exceed national boundaries
 Major spills, controlled or uncontrolled, requiring activation of large quantities and
multiple types of response resources including those from out of the region, and
possibly international sources.
 The entire Spill Management Team would be required, and would likely be
supplemented by outside organizations. A Tier 3 spill response may continue for
many weeks or months.
 Tier 3 plans cover larger oil spills at sea where the operating company may not have any
capability to deploy resources immediately and government takes the leading role.
 The oil spilled may have an impact on the property or operations of the company, or occur
near a company installation and be too large for the company to handle alone.
Spill Assessment
 It is important to define actions and information required to assess and classify the
spill size and to monitor its movements.
 The results of the spill assessment and surveillance activities will guide the Qualified
Individual/Incident Commander and Spill Management Team on resource
requirements and level of response necessary.
 Spill assessment and monitoring will inform the Spill Management Team of the
current location and projected path of the spill.
 Spill assessment will assist in the identification of potentially impacted sensitive
areas or shorelines.

 Spill occurs in different type (surface, sub-surface, crude, refined products,
continuing, contained) so it is important to identify spill type.
 It is necessary to estimate volume of spill. Colour-metric graphs and pictures are use
to define volume of spill
 Define pre-spill trajectory modelling for shoreline or offshore sensitive areas.
 Define Directions and speeds of spill movements under common wind and current
conditions.
 Development of protection strategies for sensitive areas and shorelines most at risk.
 Define data of available temperature (air and water), wind, wave, and surface current
information for the geographic response area.
 Include tables with associated information such as monthly or seasonal maximum,
minimum, mean values for wind and current speeds, temperatures, wave heights,
precipitation, etc. and average wind and current directions.

Response strategy for offshore oil spill
In-Situ burning
1.3 In-situ burning
 In-situ burning is a response option that has proven safe and effective for removing oil in the
case of an oil spill.
 In-situ burning (ISB) is a process that transforms oil into its primary combustion products of
water and carbon dioxide.
 ISB is less labour intensive than other recovery techniques and requires minimal equipment.
 It has the advantage of being more versatile in its application, as it can be applied in regions
where there is a lack of infrastructure or where habitats are particularly sensitive.
 The presence of colder temperatures and calmer conditions may increase the window of
opportunity for the effective use of ISB
Dispersant

 Dispersion of oil using either chemical or mineral additives can be an effective way to
enhance the natural biodegradation process for removing oil from the environment in the
case of a spill.
 Dispersant are an effective solution in arctic environments.
 Oil is naturally dispersed in water when waves and wind are strong enough to break an oil
slick into tiny droplets that mix into the water below.
 The extent to which this dispersion occurs depends on the type of oil and the amount of
―mixing energy‖ provided by wind and waves.
 Chemical and mineral products, called dispersants, can enhance this natural process to help
reduce the effects of spills.
 Mechanism-
 An oil dispersant is a mixture of emulsifiers and solvents that helps break oil into small
droplets following an oil spill. Small droplets are easier to disperse throughout a water
volume, and small droplets may be more readily biodegraded by microbes.

1.4 Mechanism of Dispersant
Mechanical Recovery
 Mechanical recovery is considered the primary or preferred response strategy in many
regions of the world.
 The mechanical recovery operation will typically involve the following components:
- Booms for containment of oil

1.5 Booms
A containment boom is a temporary floating barrier used to contain an oil spill
- Skimmers for recovery of oil
1.6 Skimmers
A skimmer is a device that collects and removes oil from the surface of the water. Skimmers can be
towed, self-propelled, in river currents, or even used from shore. Many types of skimmers are
available for use, depending on the kind of oil spilled and the weather conditions.
- Pumps
- Oil / water separators
- Temporary storage
 The purpose of the boom is to concentrate the oil to a thick enough layer for effective recovery
to take place.
 Containment booms are normally used in combination with a skimmer to remove oil from
the water‘s surface where it is temporarily stored before being processed and disposed of.
 Environmental and oceanographic conditions and spilled oil‘s physical properties are used
to determine the type of mechanical equipment best suited for oil recovery.
 Oil spreads less and remains concentrated in greater thicknesses in broken ice compared to
open water.
 Most mechanical recovery systems are technologies developed for open water; however,
several types of skimmers have been developed specifically for recovering oil in ice.
 Mechanical skimmers can be used to remove oil from the water surface and transfer it to a
storage vessel.

Bioremediation
 Bioremediation is the application of nutrients (fertilizers containing nitrogen and phosphorous)
to the shoreline to accelerate the natural biodegradation of the oil.
 Oil biodegradation is the natural process by which micro-organism oxidizes hydrocarbons,
ultimately converting them to carbon dioxide and water.
 The process is limited by the availability of oxygen, moisture and nutrients needed by microbes.
 The use of non-native bacteria is not recommended as most areas have indigenous bacteria that
are capable of degrading oil.
 Bioremediation is typically used as a final treatment step after completing conventional
shoreline treatment or in areas where other methods are not possible or recommended.
Mechanical removal
Shoreline clean – up
 In the event of an oil spill, it is vital to protect the Arctic shoreline from contamination
whenever possible.

 The primary response strategy in all oil spills is to contain, recover or eliminate oil on water
as close to the source as possible.
 If oil cannot be prevented from reaching the shore, the key priority is to minimize impacts to
the shoreline environment.
 Shoreline clean - up by mechanical removal involves a wide range of different tools and
techniques, reflecting the highly variable conditions that a shoreline area can represent.
 Washing or manual removal techniques are labour intensive.
 Mechanical removal is faster but generates more waste, whereas in-situ treatment minimizes
waste.
Response strategy for onshore spill
Oil Spill Contingency Plan (OSCP)
OSCP Provide a framework which draws together the various resources to deal with any oil
pollution incident.
OSCP STRUCTURE AND CONTENT
• Preparations to be made for the possibility of an oil spill
• Emergency response arrangements to be implemented if an oil spill occurs
• Recovery arrangements to be implemented if an oil spill occurs
• Current oil spill trajectory modelling that applies to the activity.
Immediate response strategy
 There are various actions required to respond to a spill incident, one of the most
important being the immediate response strategy.
 An immediate response strategy is an important reference tool that should be located
at the front of an OSCP to allow for easy access by personnel and provide clear,
immediate direction on how to respond to an incident.

 The information within the immediate response strategy should be succinct and state
the actions required to respond to a spill incident until such time that other resources
can be deployed (where required).
 This includes the response actions required to minimise/ prevent impacts on the
environment. It is expected that this response will vary from location to location.
 in the immediate response strategy, information can be included
- define the process for informing other site personnel
- Define response strategy steps and actions
- Guide on how to use response strategy
Prevention
 It is necessary to include spill sources and scenarios:
- transfer of hydrocarbons, chemicals, drilling muds
- equipment failure
- blowout
- damage of equipment/infrastructure from corrosion, dropped objects, or
collision
Preparedness
- It is important to understand the environment and sensitivities that
are covered under OSCP
- Its is important to manage a spill in the most effective way and to
minimise the potential environmental risks.
Defining and characterising the classification levels for
incidents
Level 1 incidents can be adequately responded to by the application of local or
initial resources only. (ie. the immediate response strategy)
Level 2 incidents are more complex in size, duration, resource management and risk,
and may require additional jurisdictional resources beyond that of the initial
response

Level 3 incidents require further assistance above that of a Level 2 incident
and may require the support of National and International resources.
Protection and response priorities
The OSCP must identify all sensitivities that may potentially be affected by the
worst case credible spill scenarios identified for the activities. A list of all
sensitivities in order of priority for protection should be included in the text of the
document and understanding of the environment to support the priorities and
strategies proposed in the plan must be demonstrated
Trajectory modelling
 The Regulations require an OSCP to contain ―current oil spill
trajectory modelling that applies to the activity‖.
 It is recognised that the extent of trajectory modelling differs
greatly between onshore and offshore activities
 it is important to understand how a spill may impact the
environment and this is critical to ensure adequate response
techniques are planned and implemented at the time of an incident.
 An understanding of the soil type including soil infiltration rates,
topography, and any other information that may influence the fate of a spill.
 In locations where the water table is at a shallow depth and the soil has a
high infiltration rate, the urgency to remove any surface spill of hazardous
material will be greater than that in areas with a deep water table and low
infiltration rates.

Oil spill Contaminated Soil Treatment
Soil Removal
1.7 Soil removal
If soil removal appears to be the best method for soil clean -up, a decision must be made concerning
how the soils will be managed.
Once the soils are removed, they can be independently treated (by you or your consultant) or taken
to an authorized facility for treatment or disposal. If the soils are to be independently treated,
precautions must be taken to prevent adverse environmental impacts.
Stockpiling of contaminated soils can only be conducted on a temporary basis while making
arrangements for disposal or treatment.
During this time, soils must be placed within a secure (i.e. fenced), lined, and bermed area and
kept covered at all times.
You have 30 days to either dispose of the soil at an authorized facility or to obtain a solid waste
treatment permit from the Department .
In-Place Soil Treatment
Many methods for cleaning up soil contamination in-place, or "in-situ", have been used
successfully. Examples of in-situ treatments include vapor extraction and biological treatment.
Typically, in-situ treatment can be expensive but becomes more cost effective when large
amounts of contamination are present or would be difficult to remove.
In-situ treatment methods are primarily used in conjunction with complex cleanup projects and
often require that you submit a Corrective Action Plan.

In order to properly prepare a Corrective Action Plan, extensive subsurface investigation must be
done.
Landfill Disposal
As landfill space becomes restricted, the cost of disposal of contaminated soils may go up.
Ideally, no contaminated soils would be disposed of in a landfill since this results in the problem
being moved from one location to another.
Also, should there be problems with the landfill in the future, or if cleanup of the landfill should be
required, persons who disposed of contaminated soil in the landfill may be held partially responsible
for cleanup costs.
However, until alternative disposal and treatment methods become readily available, landfill
disposal may be the most cost effective option for some cleanup projects.
Thermal Treatment
Thermal treatment is preferred over aeration and landfill disposal. This treatment method may
reduce your future liability for the contaminated soils .
Contaminated soil can be treated on-site through the use of a mobile unit or transported to a
stationary facility.
Mobile Unit – Thermal Treatment
A mobile unit is especially useful for sites that are remote from a permanent thermal treatment
facility or landfill.
Costs in hauling the contaminated soil can be saved or reduced. However, you must be careful to
ensure that your treatment site is suitable for the treatment equipment. You will need to contact
local land use authorities to make sure this activity is allowed for your site. Specific information
about the use of the mobile unit must be provided to the Department.

A solid waste permit from the Department is required (see section on "Department Approval").
There are some restrictions on how the treated soil can be reused.
Stationary Facility – Thermal Treatment
A stationary facility operates similar to a landfill from a "user" perspective. You must provide the
facility with information about where the contaminated soils originated and contamination levels.
Once your application has been approved,At this time there are no thermal treatment plants would
be approved.
Soil Aeration
While treatment processes that result in the destruction of the hydrocarbons are preferred, soil
aeration may be a somewhat less expensive means for dealing with soil contamination.
Aeration works best for gasoline contaminated soils and has limited success with diesel or heavier
hydrocarbons.
This method involves the volatilization of hydrocarbons into the atmosphere. Some states prohibit
this type of treatment because the hydrocarbons help to form ozone. Also, gasoline contains benzene.
While soil aeration may be a lower cost treatment option, it is by no means a "no cost" procedure.
Soil aeration involves more than just spreading or piling the soil and letting it sit.
The process requires the use of specific controls to prevent the creation of other problems and
considerable work is needed to ensure that treatment is effective in reducing contaminant
concentrations.
Soil aeration must include active treatment measures such as using piping and pumps to push/pull
air through the soil.

Exxon Valdez spill
It was ten years ago on March 23 that the oil tanker Exxon Valdez ran aground on Bligh Reef,
leaking 11 million gallons of oil into Alaska's Prince William Sound Although the Exxon Valdez
spill was far from the biggest oil spill in history .The area is treasured for its scenic beauty and its
wildlife, including sea otters, orcas, and many species of sea birds. Currents carried the oil 500
miles from the wounded tanker, staining 1,400 miles of beaches. At least 300,000 birds and 2,600
otters were killed. Armies of clean-up crews spent over 2 billion dollars blasting beaches with steam
cleaners and scrubbing oil from rocks by hand all under extensive national media coverage. Most
alarming of all was the discovery that the ship ran aground because the captain was drunk at the
helm. The resulting lawsuit dragged out for several years and is still undergoing appeals. Exxon has
still not paid damages to plaintiffs in the lawsuits.
Causes of Oil Spill:
 Exxon Shipping Company failed to supervise the master and provide a rested and sufficient
crew for Exxon Valdez.
 The third mate failed to properly manoeuvre the vessel, possibly due to fatigue or excessive
workload.
 Exxon Shipping Company failed to properly maintain the Raytheon Collision Avoidance
System (RAYCAS) radar, which, if functional, would have indicated to the third mate an
impending collision with the Bligh Reef by detecting the "radar reflector", placed on the next
rock inland from Bligh Reef for the purpose of keeping ships on course.
 They were not equipped with ice-berg monitoring system.
Environmental impact:
The severity of oil spill effects on the environment varies greatly, depending on the conditions of
the spill .The type and amount of oil involved, its degree of weathering, geographic location,
seasonal timing, types of habitat affected, sensitivity of the affected organism‘s life stage, and

adequacy of the response all influence the severity of environmental effects .The 10 million gallons
of oil spilled from the Exxon Valdez are known to have oiled over 350 miles of shoreline in Prince
William Sound alone
.
Effects On Birds And Marine Mammals:
Spill effects were most visible on marine birds and sea otters. These effects are becoming much less
severe as the oil breaks up into smaller patches and into weathered tar balls.
Twenty-three species of marine mammals live in the sound.
These mammals include Gray, humpback, and killer whales, various porpoises and dolphins,
harbour seals and sea otters. Of these animals, the sea otters are by far the most sensitive and
vulnerable to spilled oil .Because they are dependent upon fur for insulation, they die of
hypothermia and stress when it comes in contact with oil. .Fumes from the floating oil also may
have contributed to their deaths. As many as 2,500 of Prince William Sound‘s estimated pre-spill
population of 8,000 to 10,000 sea otters are in the western portions of the sound where they may be
exposed to oil from the Exxon Vaidez.
The number of dead, currently at 479, is not regarded as an accurate measure of the spill‘s impact
on sea otters because of the difficulty in recovering their bodies.
Effects On Fisheries And Other Marine Resources:
Oil can affect microscopic plants and animal adversely. The latter include the floating eggs and
larvae of fish that form the base of the marine food chain. In the open waters of the sound and gulf,
this impact probably will be short-lived and local because of the quick replacement of plankton by
the same organisms from unaffected areas. Recovery of their populations may take several years.
As the oil from the Exxon Valdez moves into the deeply indented coast by means of tidal and wind
action, it will affect increasingly sensitive environments. Lower-energy environments are located
deeper in fjords and bays. In high-energy environments, such as the headlands, wave action tends to
remove what oil is stranded rather quickly. In low energy environments, such as shallow bays and
marshes, oil may remain for years with only slow chemical and biological processes to degrade it.
The stranded oil will serve as a reservoir for the chronic input of oil into the sub tidal sediments,
where it may affect bottom dwelling (benthic) organisms over the long term.

Three methods were tried in the effort to clean up the spill:
1. Burning
2. Mechanical Clean-up
3. Chemical Dispersants
Burning:
On the first day of the spill, Exxon requested an open-burn permit from the State of Alaska. The
state responded the following day by authorizing an effectiveness test for burning the spilled oil,
and the test was conducted toward evening of that same day. Approximately 12,000 to 15,000
gallons were burned. Disagreements arose between Exxon and the State of Alaska about the success
of this operation.
Although the oil burned satisfactorily, there were questions about residual smoke.
Some residents several miles from the burn site reported irritated eyes and throats. No further tests
were conducted.
Mechanical Recovery:
Mechanical recovery was the preferred method of oil removal because mechanical recovery
removes oil from the environment.
Necessary recovery equipment included various booms, skimmers, and containment vessels.
Equipment assembly was labor intensive and time consuming.
Booms required personnel who could attach sections, set, and tend them. Some booms are
inflatable, but one such boom sank on the first day of the spill. The booms had to be towed slowly
to prevent damage. Since Prince William Sound is very large, the time necessary to relocate booms
to different areas of Prince William Sound was considerable.
Skimmers are mechanical devices that remove oil from water. They require tending during
operation.
Skimmers must be directed to oil locations from aircraft to assure greater efficiency, thereby
increasing coordination problems. Few aircraft were available initially to coordinate the deployment
of skimmers. With limited personnel available to monitor and repair skimmers operating great

distances from one another, long periods of inactivity resulted when they became disabled. When
breakdowns required shop work, they were towed back to
Valdez.
For example, one skimmer with a gear box problem required 12 hours to be towed to Valdez
for repairs. The repair shop was already working on two other skimmers and repairs took all night
to complete.
The third component of a mechanical recovery system is the temporary storage vessel. A small,
temporary oil-containment device (oil bladder) attached to the skimmer must be emptied at a large
oil recovery barge when full. This procedure was slow because the transfer pumps had difficulty
moving the heavy, grease-like material. Consequently, vessels would often queue up at the recovery
barge.
Chemical Dispersants Method:
Chemical oil spill dispersants are substances applied to spilled oil in order to disperse the oil into
the water column rather than leaving it floating on the surface in a slick. Neither the burning nor the
mechanical clean-up was truly effective in cleaning the oil, so dispersants were the only viable
option left, however they were still in the trial phases. The dispersant Cortex 9580 was applied the
same day as the spill by helicopter, but because of little movement by the waves, the dispersant was
not able to properly interact with the oil, and was rendered useless, and its use was discontinued.
It was later discovered that the dispersant used, Cortex 9580, was toxic to both the wildlife and
the clean-up workers. Upon investigation, it was discovered that many organisms had accumulated
the dispersant in their body at dangerously high concentrations. Two particular species that were
affected by the dispersants include the Pacific herring and the pink salmon embryos. Although over
time, the salmon species was able to recover, the same cannot be said for the herring population,
which even after all these years, has still not returned to its population before the spill.

PART-II
[INDUSTRIAL OUTLOOK]
Common Causes Of Oil Spill
1. When oil tankers have equipment faults. When oil tankers break down, it may get stuck on
shallow land. When the tanker is attempted to move out of shallow land, abrasion may cause a hole
in the tanker that will lead to large amounts of oil being released into the oceanic bodies. However,
although this form of oil spill is the most commonly known and has the highest media attention,
only 2% of oil in water bodies is a result of this action.
Oil tankers are only one source of oil spills. According to the USCG (United States Coast Guards),
35.7% of the volume of oil spilled in the United States from 1991 to 2004 came from tank vessels
(ships/barges), 27.6% from facilities and other non-vessels, 19.9% from non-tank vessels, and 9.3%
from pipelines; 7.4% from mystery spills. On the other hand, only 5% of the actual spills came from
oil tankers, while 51.8% came from other kinds of vessels.
2. From nature and human activities on land. The large majority of oil spilled is from natural
seeps geological seeps from the ocean floor as well as leaks that occur when products using
petroleum or various forms of oil are used on land, and the oil is washed off into water bodies.
3. Water Sports. Other causes of oil spills are spills by petroleum users of released oil. This
happens when various water sports or water vehicles such as motorboats and jet skis leak fuel.
4. Drilling works carried out in sea. When drilling works carried out in the sea, the oil and
petroleum used for such activities are released into the sea, thus causing an oil spill.
5. Equipment breaking down: The International Tanker Owners Pollution Federation has tracked
9,351 accidental spills that have occurred since 1974. According to this study, most spills result
from routine operations such as loading cargo, discharging cargo, and taking on fuel oil. 91% of the
operational oil spills are small, resulting in less than 7 metric tons per spill. On the other hand, spills
resulting from accidents like collisions, groundings, hull failures, and explosions are much larger,
with 84% of these involving losses of over 700 metric tons.

6. Accidental spills during:
 Storage – oil and oil products may be stored in a variety of ways including underground and
aboveground storage tanks (USTs and/or ASTs, respectively); such containers (especially
USTs) may develop leaks over time;
 Handling – during transfer operations and various uses;
 Transport:
 Big oil spills (up to million and hundreds of million gallons) on water or land
through accidental rupture of big transporting vessels (e.g., tanker ships or tanker
trucks). For example, Exxon Valdez spill was a massive oil spill off the Alaskan
shoreline due to ship failure which happened in late 1980‘s– oil spill pollution
residuals from that spill are still affecting our environment (as of 2010 – several
decades after the spill).
 Smaller oil spills through pipelines and other devices also happens and their impact
is mainly due to a large number of usually minor spills;
7.Offshore drilling – we are currently experiencing the massive oil spill in the Gulf of Mexico with
its hard to predict consequences on environment, marine life and humans as the spill continues since
April 22, 2010 and it may take a while until a solution is implemented.
8. Routine maintenance activities such as cleaning of ships may release oil into navigable waters.
This may seem insignificant, however due to the large number of ships even few gallons spilled per
ship maintenance could build up to a substantial number when all ships are considered.
9. Road run-off – oily road run-off adds up especially on crowded roads. With many precipitation
events, the original small amounts of oil from regular traffic would get moved around and may
build up in our environment
10. Intentional oil discharges – such as those through drains or in the sewer system. This include
any regular activities such as changing car oil if the replaced oil is simply discharged in a drain or
sewer system.
11. Indirectly through burning of fuels, including vehicle emissions – would release various
individual components of oils and oil products such as a variety of hydrocarbons

Offshore Pipeline Failure
An oil spill in marine waters offshore California can be a devastating and disastrous event. Many
factors can be Managed to minimize the environmental, political, and financial impacts from such a
spill.
Among these factors are Preplanning, careful execution of a sound response, and proactive
attention to the media.
And one of the major reasons behind the spilling of oil is nothing but the pipeline failure. Which
may cause due to many reason as listed below. Natural seepage of oil can also cause the same
without no or a very little human interference.
What are the major causes of pipeline failure?
 Maintenance failure: Maintenance failure is one of the most common causes which are
clearly a human failure. Poor maintenance activity may cause severe damages to the
pipelines which may include rusting, formation of caves on the linepipe wall etc. A proper
maintenance may expand the lifeline of a pipeline significantly.
 Tectonic activity: Tectonic activity includes the normal tectonic movement which affects the
pipeline adversely as the pipeline has a little elasticity and can‘t bear heavy load caused by
the generated stresses.
 Natural Hazards: Natural hazards are an accidental case which has nothing to do with human,
natural calamities like earthquake, landslides etc. occur, pipelines a susceptible to rupture
from its weakest point.
 Impact from marine life: Marine life includes all kinds of living creatures which is living in
the sea.
 Tidal waves: Tidal waves don‘t affect the pipeline in a short run, but they do when the
pipeline is laid fore decades of service. Because the tidal waves generate immense stress on
the pipeline whi may cause rupture even is the pipelines are not well designed.
 Impact due to marine vehicles which causes heavy impulsive waves on the pipeline
 Elastic creeps: Elastic creeps are nothing but the creeps generated by the normal underwater
sea waves, elastic creeps don‘t affect in a short run. But they are pretty dangerous as its
alittle harder to spot out creped zone

How the pipeline failure affects the environment?
Pipeline failure may occur both onshore as well as offshore, but the most critical one is the offshore
one. Because not only it‘s much harder to treat but it also keeps affecting the marine animals and
plants in an adverse manner. However briefly if we look at the impacts that is left behind due to the
spilling of oil.
Spilling of oil mainly spreads all over the water surface and reduces the penetration of sunlight, and
aquatic plants are hugely sensitive to sunlight.
In another case those spilled oil creates problem for fishes as oil gets stick to their fins, it makes
them harder to swim.
Wildlife Impacts. The Oiled Wildlife Care Network, a state wide organization of scientists and
technicians dedicated to respond to hazardous substance releases in support of wildlife operations,
responded to a request for assistance. They set up a mobile facility staffed with trained wildlife
handling personnel to manage wildlife rescue and rehabilitation operations. Waterfowl were
recovered – both dead and alive. Due to the natural oil seeps in the area, many oil fingerprint tests
had to be done to determine the source of oil. Further, necropsies had to be performed on several
specimens to determine if the oil was the cause of mortality. Twenty-four captured birds were
cleaned at the field location and then flown via helicopter to a special bird cleaning and
rehabilitation facility in Berkeley California. Many birds were cleaned and ultimately released from
both the field location and from the Berkeley facility. Qualified personnel euthanized other birds.
The final count on wildlife impacts is still being determined as part of the process of the natural
resource damage assessment, and will be concluded soon.
No marine mammals were found to have been impacted by the spill.
Before we jump into the remedy we shall see the preparedness methods first, as its much more
important to prevent such mishaps than to cure it.

So here we see the,
Key elements of oil spilling preparedness and responses for onshore pipelines
3. Risk assessment
4. Environmental sensitivities
5. Pipeline response strategy
6. Equipment types and quantity
7. Transboundary issue
8. Stakeholders management
And now as we know the prevention methods we must know the methods to cure such accidents,
Technologies that are currently in use to tackle with the spillage of oil
5. Forward-Looking Infrared Radar. Each oil spill response vessel was equipped with
forward-looking infrared radar (FLIR) in 1996 to detect oil at night or in low visibility
situations. When the vessel Mr. Clean III came on site in the black of night, the spill was
clearly visible on the FLIR screen, allowing the crew to mark the location on a chart and
determine the approximate size of the spill. Based on this success, three other OSRO‘s have
added FLIR to their vessels.
6. Flag Buoys. Clean Seas designed and manufactured a simple buoy with a bicycle flag
attached to aid in tracking oil on water. Each vessel has five or more of these buoys in its
inventory. Mr. Clean III deployed these around the spill. They are also clearly visible on the
FLIR. Based on the success of this, Clean Seas has manufactured an additional 100 of these
buoys for inventorying on each of the platforms for immediate deployment by rig personnel
in the event of a spill or drill.
7. Lori-Brush Systems. The Mr. Clean was converted to a Lori-brush system in 1996 and this
spill was the first opportunity to use the system. With the heavy crude, other recovery
systems were less than efficient while the brushes continued to pick up the oil. Slight
modifications have been made to the after-doors on the system and to the hydraulic rams to
allow for even more efficient operation of this system.
8. Skimming Barges. One-hundred-barrel barges were used for the first time on this spill and
were towed for the first time utilizing the fishing vessels. The combination of the Lori-brush
systems with these barges was very effective and economical to use and clean. However,
there was some

Difficulty in removing the heavy oil from the barges, so a system of heating coils has been
installed to allow localized heating of the heavy oil around the pump suction. A typical
oilfield de-waxing service will be utilized for this system.
Prediction of Rate And Volume Of Oil Spill In Horizontal And Inclined
Pipelines
Here in this section we shall see how the spillage of oil is quantified in order to estimate the total
loss of oil and again, it helps us to figure out the measure we can take in order to tackle with the
spillage.
It is just like in such case when spilling of oil is not that significantly higher we use the bacterial
degradation method, and again in its counterpart we use Solidification method.
So here the estimation of Oil spillage is important as we can see.
Accurate prediction of total quantity of oil spills has become essential in designing bioremediation
technology for effective remediation, clean-up of oil polluted environment, and for proper
assessment of oil polluted environment. Hydrodynamic principles were used to derive a simple
analytical model to predict the rate and total volume of oil spills in both horizontal and inclined
pipeline. The model result was validated with experimental result at various leakages pressure and
leakages radii.
Knowledge of the quantity of oil that spills from a pipeline in an environment is very important
becauseit leads to accurate determination of the amount of bacteria that can secrete the required
volume of enzymes that can decompose and clean up the equivalent volume of oil spill. It also helps
in adequate evaluation and assessment of environmental implications and extent of oil spill in any
environment. Thus, this study is aimed at achieving the following objectives:
1. To develop analytical mathematical model for estimating and predicting rate of flow of oil spill
from horizontal and inclined pipelines; and the volume of the spill,
2. To carry out experimental work in the laboratory,
3. To validate the model with empirical data gotten from the laboratory, and
4. To compare the results from (3) with measured empirical values of volume of oil spill from
repeated experimental values.

PIPELINE PROTECTION FROM HEAVY SUB-SEA WAVES
There are many methods used to protect offshore pipelines: sand, grout or cement bags, burying,
concrete or cathode coating, and trenching, to name a few. Most methods address ancillary issues
like separation, support, erosion, expansion of infrastructure, pipeline corrosion, and ensuring that
the pipeline infrastructure itself is not detrimental to the environment surrounding it. Only one form
of pipeline protection technology however, found itself in the midst of a battle between the seafood
industry of south-eastern Louisiana, the oil and gas industry, and environmental agencies: concrete
mattresses, also commonly referred to as concrete mats.
A recently completed project off the coast of California required a tailor-made solution for an older
pipeline needing protection for another 20-30 years. In California, a permanent CP monitoring
system replaced the usual anodes in the concrete to protect and extend the life of the pipeline. The
CP monitoring system was connected to the pipeline by a clamp, and in order to protect the clamp
from trawling, a four-six block hole was created in the mat. While this particular project was
completed in more shallow water – around 300 ft deep – Flannery contends that because concrete
mats can be used in nearly any water depth, this technology could be employed much further
offshore.There are a few instances in which products are still in danger of moving under concrete
mats, primarily in water less than 300 ft deep or where pipelines are located at the mouth of a river.
Of course, without any protection at all, the unthinkable could happen: pipelines could jump or
break. Furthermore, the environment around the pipeline could be harmed indefinitely from
exposure. Clearly, pipeline protection is critical to a pipeline‘s long-term integrity and success.
Environmental impact:
In addition to being used for pipeline separation and pipeline crossing, another notable advantage to
using concrete mats – and one that extends beyond the industry—is the product‘s inherent
environmental friendliness. Concrete was cited as environmentally sound by the IMCA, and the
mats are used to combat erosion beneath and surrounding pipelines. In cases where the soil under
the pipeline is eroding, the mat can be used to span that area, thereby halting erosion underneath. It
is generally regarded as the technology that is the least obtrusive to operations and, equally
importantly, the environment and vegetation below and around the mat.

ESTIMATION OF SPILL VOLUME
The Pipeline Oil Spill Volume Estimator includes two methods that can be used to calculate the
amount of oil that will escape from a leaking pipeline. The Pocket Guide and an associated
computer model were developed by SINTEF and Well Flow Dynamics under a contract funded by
the Minerals Management Service. The ―Initial‖ volume calculation method is intended to be a first
best guess on the amount of oil that has been released so that spill responders can mobilize adequate
equipment to the spill site. It is to be used when data on the event are limited and quick decisions on
response strategy are mandatory to minimize spill impacts. The ―Advanced‖ method allows for the
refinement of the spill volume estimate as the spill response proceeds. More variables are required,
but the refined estimate will provide a more realistic volume for assisting in developing response
strategies and revising incident action plans.
Both the ―Initial‖ and ―Advanced‖ methods assume:
• A single horizontal pipeline segment;
• A full pipeline break or rupture.
These methods are therefore not applicable to pinhole leaks or other small pipeline fractures. The
computer model removes the limitations found in the ―Initial‖ and ―Advanced‖ methods by
allowing the user to input pipeline leak hole size, fluid properties, and variable water depths. The
users can also create a pipeline network that may contain many pipeline segments. Model output
includes reports that show pipeline leakage rates versus time and cumulative leak rates with reports
being in both tabular and graphic formats.
Required datas
This calculation procedure requires the following data:
• Pipeline internal diameter, IDpipe [in]
• Pipeline length, Lpipe [ft]
• Pipeline pressure, Ppipe [psi]
• Gas-oil-ratio, GOR [scf/stb]
• Water depth at rupture location, d [ft]
• Pipeline flow rate, Q [stb/d]
• Time before shut-in, t [min]

According to the organisation SkyTruth these parameters are should be considered for enhanced
estimation of Spill volume.
Computing Volume
An oil slick in the open ocean is typically a very thin layer of oil covering a large area, often many
square miles in extent. So in order to calculate the volume of a slick we need to measure or
estimate the area it covers, then estimate the average thickness over that area. Then we multiply the
area times the thickness to get the volume.
Estimating Surface Area
Measuring the area is a fairly straight-forward and accurate process with satellite imagery - we
simply trace a line around the visible edges of the slick and compute the area inside that
boundary. For oil spill reports where we do not have imagery, we use the reported length and width
of the slick to compute the rectangular area which contains the slick.
Estimating Thickness
Estimating thickness, however, is another matter. One way to estimate the thickness of an oil slick
is to observe it's "colour" and assign a thickness based on established guidelines for the range of
thicknesses that can produce a slick of that colour (e.g. "Rainbow sheen"). Tables and guidelines
for visual estimation of oil spill volumes are published by the National Oceanic and Atmospheric
Administration (NOAA) on their response and restoration website.
Unfortunately, when using satellite imagery, especially radar (SAR) imagery, we are not able to
observe the spectral characteristics that create the apparent colour of a typical oil slick, so we
cannot use this method. Instead, we use a rule of thumb that provides a reasonable estimation of the
minimum average thickness that makes an oil slick at sea visible on satellite imagery.
Based on past experience, and the judgement of other experts, SkyTruth has determined that a good
rule of thumb for estimating the thickness of an oil slick visible in a SAR image is that the total area
is on average at least 1µm (one micron, or 1 millionth of a meter) thick. The actual thickness varies
across the whole area, as some parts of the slick may be thicker than the average, and other parts
thinner.
By measuring the area of the visible oil slick in a SAR image, and assuming the average thickness
of the oil across that area is at least 1µm, the minimum volume of oil in the slick can be calculated.

2. Materials and methods
Simple analytical equations were derived from principles of fluid mechanics with scientific
assumptions to mimic pressure, velocity and the forces that act along a pipeline. Experimental work
was conducted in the laboratory under laminar flow condition in order to generate empirical data to
validate the effectiveness of the analytical equations that were derived.
About 2bbl of diesel oil was flown through a horizontal pipeline of about 16ft. A total of five holes
were created along the pipe at different points in order to allow oil to spill from the holes. A pump
was connected to the pipe and the inlet pressure was measured as well as the pressure at the five
leaking points along the pipe, using six manometers. Graded containers were placed at each leaking
point to collect the quantity of oil that spills out. The time for the oil to spill was measured by stop
watch. The diameters of the leaking holes were measured with vernier callipers and the density of
the oil was measured. The laboratory units of all the measured parameters were converted to field
units. Empirical values were used to validate analytical values using the trends of parameters
predicted and those measured in the laboratory.
3. Development of Model
The model was developed based on the following assumptions:
1. Laminar flow
2. Incompressible fluid
3. Surface area of leak is assumed circular in nature
4. Average radius of the leak radii is taken as the radius of the leak.
The estimation of the pipeline starts with a simple equations
Inlet Pressure + Pressure of oil column + kinetic energy = constant

By deriving it further for Inclined and Vertical pipes we can reach to these two formulas for horizontal and vertical
pipes respectively,
For horizontal spill estimation,
For Vertical spill estimation
MUMBAI WAVE CONDITION

The observed large tidal range (up to 3 M during spring tide) at the Mumbai High offshore region
located near the continental shelf break, off the central west coast of India, is described based on
simultaneous tidal measurements (30 s average) at 15 Min sampling interval using four tide gauges
deployed from an oil drilling platform of the Oil and Natural Gas Corporation of India. All the four
gauges provided identical measurements. The measured tides were harmonically analysed and the
amplitudes and phases of the five major constituents, i.e. M2, S 2, K1, O1 and N2 were compared
with those observed at the closest coastal station (Apollo Bandar, Mumbai). It was found that the
observed tidal range at this offshore location was unusually larger than those found in the open-
ocean regions. This large tidal range was found to be associated with the large width of the
continental shelf off the central west coast of India.
Field measurements were carried out at the offshore platform called ‗ICP‘ of the ONGC at the
Mumbai High offshore region. The latitude and longitude of the location are 19°21′N and
71°18′11′′E. The ICP platform is located approximately 160 km from the shore. The water depth at
this location is about 65 M. Measurements consisted of deployment of four tide gauges and
installation of an autonomous weather station (AWS). Observations were carried out during the
period between 22 February and 2 April 2007. Three of the four tide gauges were based on absolute
metal resistance strain gauges developed in-house and the fourth one was based on absolute piezo-
resistive strain gauge developed in-house, whose performance was found to be adequate for
oceanographic and limnological studies. Technical details may be found elsewhere. All the gauges
used in the present study measured absolute pressure (i.e. atmospheric pressure plus the pressure
exerted by the water column above the transducer).
An important result from the tidal measurements at Mumbai High offshore region was that the
observed tidal range of about 3 m at spring tide phase was considerably larger than the open-ocean
tide. Amplitudes of the major tidal constituents M2, S2, and N 2 at Mumbai High were nearly half
of those at Apollo Bandar, which is the closest shore station. Selective amplification of certain tidal
constituents is often observed in some estuaries and gulfs. Amplification of semi-diurnal tides in the
Gulf of Kutch and Gulf of Khambhat on the Northwest coast of India, arising partly from quarter-
wavelength resonance 13–15, is an instance of selective amplification of tidal constituents. On the
shelves, tidal currents that are driven by tides, are large compared to the currents generated by
winds or driven by buoyancy. Shelves have depths typically less than 200 m, and since tidal
wavelengths are much larger (of the order of 1000 km), these waves propagate
As shallow-water waves. A description of the basic processes of tidal propagation on continental
shelves may be found in Dyke16.

Conditions at Gulf of Mexico
GULF OF MEXICO
(Oceanography part)
Surface currents are ocean currents in which the moving water lies between the surface and a
maximum depth of about 500m. Currents that are no deeper than 200m are usually caused by the
wind pushing on the water. Currents as deep as 500m usually are caused by forces associated with
the rotating Earth and are called geostrophic (Earth-turned) currents. In our exploration of the Gulf
of Mexico we are concentrating our research on the ecology below 500m and are very interested in
the Gulf Loop, an example of geostrophic flow that strongly influences our exploration area.
The Gulf Loop flows in through the straits of Yucatan and exits through the straits of Florida.
Sometimes it is confined to the coast of Cuba. At other times, it flows along a long loop to the
North before turning south and eventually exiting through the straits of Florida. This elongated loop
is unstable and pinches off large eddies that spin clockwise as they drift westward. The eddies
eventually spin down in the western Gulf. They sweep over the bottom and may have a great
influence on the ecology.
The Gulf is rather isolated, and we know that it is 3600m deep. The Yucatan Strait is about 2000m
deep, but the Florida Strait is only about 800m deep. This means that the deep water in the Gulf
flows in from the Caribbean, not directly from the Atlantic. In effect, the islands of the eastern
Caribbean form a very leaky wall with many shallow gaps, but only a few deep gaps. Just as this
wall limits deep water flow, it might partially isolate animal populations in the deep Gulf from the
populations in the larger deep Atlantic.
Dr. Susan Welsh of LSU has provided us with preliminary information about the deep currents
using computer simulations and a program called the Modular Ocean Model. Her data indicate that
in the expedition area of the northern Gulf, the sea-floor at 500-1000m experiences average currents
to the east at a mean velocity of 10 centimetres per second (cm/s). Deeper in the northern Gulf
(2000m to 3000m) the currents reverse, nearly following the isobaths to the west or south-west. The
mean flow along the slope is closer to 5 cm/s. Off west Florida, below 1000m, the currents flow to
the north with mean currents less than 10 cm/s, increasing with depth. Eddies are spawned by the
Gulf Loop eddies that are created with the general flow. Apparently, these eddies can reach bottom
speeds of up to two knots. These spinning eddies move water across depths (up and down) of
several hundreds of meters and may be the source for transient high velocity currents.

Currents are generated by the wind condition and hence wind must be considered before the
currents and tides and hence the wind wave model
In fluid dynamics, wind wave modelling describes the effort to depict the sea state and predict the
evolution of the energy of wind waves using numerical techniques. These simulations consider
atmospheric wind forcing, non-linear wave interactions, and frictional dissipation, and they output
statistics describing wave heights, periods, and propagation directions for regional seas or global
oceans. Such wave hind-casts and wave forecasts are extremely important for commercial
interests on the high seas. For example, the shipping industry requires guidance for operational
planning and tactical sea-keeping purposes.
For the specific case of predicting wind wave statistics on the ocean, the term ocean surface wave
model is used.
Loop Current of GOM
LOOP Current:
Definition: [The Loop Current is a warm ocean current that flows northward between Cuba and
the Yucatán Peninsula, moves north into the Gulf of Mexico, loops east and south before exiting to
the east through the Florida Straits and joining the Gulf Stream. Serving as the dominant circulation
feature in the Eastern Gulf of Mexico, the Loop Currents transports between 23 and 27 sverdrups
and reaches maximum flow speeds of from 1.5 to 1.8 meters/second.]
The Loop Current is an ocean current that transports warm Caribbean water through the Yucatan
Channel between Cuba and Mexico. The current flows northward into the Gulf of Mexico, then
loops south-east ward just south of the Florida Keys (where it is called the Florida Current), and
then just west of the westernmost Bahamas. Here, the waters of the Loop Current flow northward
along the U.S. coast and become the Gulf Stream. With current speeds of about 0.8 m/s, the Loop
Current is one of the fastest currents in the Atlantic Ocean. The current is about 200 – 300 km (125
– 190 miles) wide, and 800 meters (2600 feet) deep, and is present in the Gulf of Mexico about 95%
of the time. During summer and fall, the Loop Current provides a deep (80 – 150 meter) layer of
vary warm water that can provide a huge energy source for any lucky hurricanes that might cross
over.
The Loop Current commonly bulges out in the northern Gulf of Mexico and sometimes will shed a
clockwise rotating ring of warm water that separates from the main current (Figure 1). This ring of
warm water slowly drifts west-southwest ward towards Texas or Mexico at about 3-5 km per day.
This feature is called a "Loop Current Ring", "Loop Current Eddy", or "Warm Core Ring", and can

provide a key source of energy to fuel rapid intensification of hurricanes that cross the Gulf, in
addition to the Loop Current itself. The Loop Current pulsates in a quasi-regular fashion and sheds
rings every 6 to 11 months. When a Loop Current Eddy breaks off in the Gulf of Mexico at the
height of hurricane season, it can lead to a dangerous situation where a vast reservoir of energy is
available to any hurricane that might cross over. This occurred in 2005, when a Loop Current Eddy
separated in July, just before Hurricane Katrina passed over and "bombed" into a Category 5
hurricane. The eddy remained in the Gulf and slowly drifted westward during September. Hurricane
Rita passed over the same Loop Current Eddy three weeks after Katrina, and also explosively
deepened to a Category 5 storm.
Here is an example, in which the Tidal chart of CEDAR KEY which is situated in Gulf Of Mexico.
Were the maximum splash level of water is plotted against the time. Here we can see the 2 PM is
the ideal time when the splash of water is most dominating.
Other
Datum from
Gulf Of
Mexico
The Gulf of Mexico is an ocean basin largely surrounded by the North American continent. It is
bounded on the north-east, north and north-west by the Gulf Coast of the United States, on the
south-west and south by Mexico, and on the south-east by Cuba. The U.S. states of Texas,
Louisiana, Mississippi, Alabama and Florida border the Gulf on the north, which are often referred
to as the "Third Coast" in comparison with the U.S. Atlantic and Pacific coasts, or sometimes the
"south coast", in juxtaposition to the Great Lakes region being the "north coast." One of the gulf's
seven main areas is the Gulf of Mexico basin.
The Gulf of Mexico formed approximately 300 million years ago as a result of plate tectonics. The
Gulf's basin is roughly oval and is approximately 810 nautical miles (1,500 km; 930 mi) wide and
floored by sedimentary rocks and recent sediments. It is connected to part of the Atlantic Ocean
through the Florida Straits between the U.S. and Cuba, and with the Caribbean Sea (with which it
forms the American Mediterranean Sea) via the Yucatan Channel between Mexico and Cuba. With
the narrow connection to the Atlantic, the Gulf experiences very small tidal ranges. The size of the
Gulf basin is approximately 1.6 million km2 (615,000 sq mi). Almost half of the basin is shallow

continental shelf waters. The basin contains a volume of roughly 2,500 quadrillion litres (550
quadrillion Imperial gallons, 660 quadrillion US gallons, 2.5 million km3 or 600,000 cu mi).
A COMPARISON BETWEEN GULF OF MEXICO AND MUMBAI OFFSHORE
GULF OF MEXICO MUMBAI
Reported by NOAA/CDIP high tech & weather
instruments.
The observed large tidal range (up to 3 m during
spring tide)
The wind swell (3 - 10 second period) which is
the chop generated by local and current winds.
The measured tides are harmonically analysed
and the amplitudes and phases of the five major
constituents, i.e. M2, S 2, K1, O1 and N2 were
compared with those observed at the closest
coastal station (Apollo Bandar, Mumbai)
and a ground swell (10 - 25 sec) which has
travelled possibly 5000 miles
Tidal waves at the oil zone were comparatively
higher than the mid oceanic region.
Wind swells are steeper and more dangerous at
sea
Expected cause of the higher tidal waves is due
to the wider continental shelf.
Long period swells hit the shore with more
power, but may be hardly noticed when you are
out at sea because of 20 second spacing between
crests.
The ICP platform is located approximately 160
km from the shore and, Observations were
carried out during the period between 22
February and 2 April 2007.
Depending on the weather, water temperatures
can run 5 to 7 degrees cooler or warmer than
other oceanic regions.
Amplitudes of the major tidal constituents M2,
S2, and N 2 at Mumbai High were nearly half of
those at Apollo Bandar
Surface currents are ocean currents in which the
moving water lies between the surface and a
maximum depth of about 500m
Selective amplification of certain tidal
constituents is often observed in some estuaries
and gulfs
Currents that are no deeper than 200m are
usually caused by the wind pushing on the water
Amplification of semi-diurnal tides in the Gulf
of Kutch and Gulf of Khambhat on the
northwest coast of India.
Currents as deep as 500m usually are caused by
forces associated with the rotating Earth and are
On the shelves, tidal currents that are driven by
tides, are large compared to the currents

called geostrophic (Earth-turned) currents generated by winds or driven by buoyancy
Highly turbulent waves known as Loop waves
are propagating towards the shoreline, precisely
Florida and new jersey.
Shelves have depths typically less than 200 m
This elongated loop is unstable and pinches off
large eddies that spin clockwise as they drift
westward
And since, tidal wavelengths are much larger (of
the order of 1000 km). these waves propagate
as shallow-water waves
Formation of Eddies are very much usual in the
GOM territory, which are of downspin nature.
Loop current velocity: 1.5 to 1.8 meters/second
The current is about 200-300 km (125-190
miles) wide, and 800 meters (2600 feet) deep,
and is present in the Gulf of Mexico about 95%
of the time
With current speeds of about 0.8 m/s, the Loop
Current is one of the fastest currents in the
Atlantic Ocean
The Loop Current pulsates in a quasi-regular
fashion and sheds rings every 6 to 11 months
These currents are mainly generated by the wind
condition, which is very turbulent one and flows
in an oval geometry through-out the year.
Average spill velocity estimated to be 0.5-0.8 M
per hour for heavy oil and light oil may reach
upto 20 M per hour.
Light oil face heavy dispersion below the water
surface and hence its very very hard to deal with.

PIPELINE STANCE TAKEN IN GULF OF MEXICO
Gulf Of Mexico Pipeline Data
Corrosion is the leading cause of failures of sub sea pipelines in the US. Gulf of Mexico. Third-
party incidents, storms, and mud slides are additional principal causes of offshore pipeline failures.
For small size lines, additionally, failures due to external corrosion were more frequent during the
period studied than internal corrosion. In medium and large-size lines, failures due to internal
corrosion were more frequent than those due to external corrosion.
The significant components of a typical offshore pipeline system transporting hydrocarbons are:
Platform risers, expansion loops or thermal offsets, sub-sea valves and fittings, tie-in spools, and the
main trunk line or the infield flow line.
Failure data published by the MMS' (United States Mineral Management Services ) for about 690
failures that occurred during 1967-87 was compiled into a personal-computer data base.
Although the MMS data on pipeline failures are the most comprehensive source of information
available, the information for some of the failures reported is either insufficient or unclear. In those
instances, some judgement and assumptions had to be exercised during compilation of these data.
The significant increase in failures since 1975 can be attributed to the increase in the pipeline
population, aging of the pipelines installed earlier, and the increased offshore construction activity.
PIPELINE DATAS
Pipeline sizes:
 Small, 2-6 in.
 Medium, 8-16 in.
 Large, 18-36 in.
Only 3% of the failures were associated with large-diameter lines, whereas 59% were associated
with small-diameter lines.

The total percentage of pipeline failures grouped under each failure-cause category. The various
causes of pipeline failures have been grouped into five principal categories:
1. Material or equipment failure
2. Operational
3. Corrosion
4. Storm/mud slides
5. Mechanical damage/third-party incidents.
These failure-cause categories are discussed in detail in later sections.
Next to corrosion (50% of failures), mechanical damage due to third-party incidents (20%) and
storm/mud slide-induced damages (12%) are the major sources of pipeline failures.
The distribution of failures based on the type of product transported.
The majority of failures occurred on oil lines (51%).
Although gas pipelines have a larger population than oil lines, in the Gulf of Mexico their reported
failure rate was only 28%. This may be due to relative ease of leak detection in oil lines as
compared to gas lines.
Other possible reasons for the disproportionate number of failures associated with oil lines have
been given by Andersen and Misund .
2 They need further evaluation.
Multiphase lines and other types of lines, such as NGL, condensate, test lines, etc., grouped under
the miscellaneous category, each had 3% of the total failures.
FAILURE CAUSES (As Per the GOM Conditions)
The following section presents a detailed discussion of the different causes of pipeline failure.
MATERIAL FAILURES
Material failures include instances where the pipe material ruptured or the weld cracked and failed.
Equipment failures were primarily due to leakages or malfunctioning of fittings such as flanges,
clamps, valves, etc.
Out of the 60 total failures that were grouped under this category, about 23% were attributed to
material failure, and the remaining 77% were attributed to equipment failure.

OPERATIONAL PROBLEMS
Only seven failures were attributed to operational problems. These were mostly the result of lines
being over-pressured either during the normal operation or the pigging operation.
CORROSION FAILURES
Three subcategories comprise corrosion failures.
In the first two cases, the failure was clearly identified as the result of either internal or external
corrosion. In the third case, the origin of the corrosion was not clearly identified. We will refer to
this as general corrosion.
Out of the 343 total cases of corrosion failures, 15% resulted from internal corrosion, 46% from
external corrosion, and 39% from general corrosion.
The number of total corrosion failures per pipe size. This figure shows that the corrosion failures
have been highest among the small-size pipelines.
Further evaluation of these data showed that for the smaller-sized pipe, external corrosion failures
were more common, whereas for medium and larger-sized pipe internal corrosion was more
common. This latter observation is consistent with the observation made by Andersen and Misund.
About 78% of the total corrosion failures occurred on the platform, in the riser section or its vicinity
on the seabed, and 20% occurred on pipelines on the seabed away from the platform.
Regarding the distribution of corrosion failures, based on the pipeline product, 27% occurred in gas
lines, 49% occurred in oil lines, and in 17% of the cases, the product was not identified.
STORMS, MUD SLIDES
There were 63 incidents of pipeline failures as a result of storm loading. From these, about 87%
were among small-size lines.
The majority of storm damage incidents (83%) occurred on or near platforms. There were 19
incidents of damage due to mud slides which mostly resulted from storms. Most of the failures due
to mud slides were on medium-sized pipe (74%) and on the seabed away from the platforms.
MECHANICAL DAMAGES
The principal sources of mechanical damage to pipelines are anchors and anchor lines, work and
supply boats, construction vessels, and trawlers.

There were 70 incidents of damage due to anchors, wire ropes, etc. From these, 34 failures occurred
near platforms, and 33 failures occurred on the seabed away from platforms. Most of the anchor-
damage incidents occurred on small (30) and medium (37) size pipelines.
The majority of failures needed spool-piece repair, and only in seven cases could clamp repair be
implemented.
Damage incidents due to work boats or supply boats totalled 14, out of which 9 were on small-size
lines and 5 were on medium-size lines. Ten failures occurred on or near the platforms. The majority
of these incidents resulted from boats colliding with riser pipes during severe weather conditions.
The current practice of routing risers inside the jacket in the splash zone should reduce these types
of failures in the future.
Construction-vessel failures included mishaps during pipe laying, trenching with jet sleds,
erroneous setting of jack ups, impact from dropped objects, and movement of heavy objects on the
seabed.
Out of the 20 reported failures under this category, 16 were associated with small-sized pipes.
Eleven of these incidents occurred around the platform and 8 on the seabed away from the platform.
The potential for damage to pipelines from impact with trawling gear in the Gulf of Mexico is not
as severe as in the North Sea. Nevertheless, there were 10 reported cases of damage to pipelines
from trawling gear, 5 on small sizes, 3 on medium sizes, and 2 on large-sized pipelines. Most of
these incidents occurred away from the platform.
Cathodic protection:
Cathodic Protection Surveys
Close-interval cathodic protection surveys are the most logical strategy, but strangely enough,
operators in the Gulf of Mexico survey very little. When a survey is actually run, it is usually of
little value because the method used (trailing wire) inherently produces erroneous data.
There are accurate survey systems available; these either involve physically contacting the line at
intervals or utilizing remotely operated vehicles (ROV's) to track the pipeline and carry reference
electrode arrays above the pipeline at known locations. This type of survey will let the operator see
the condition of the line and make informed decisions regarding retrofitting.

Retrofit Anodes on Pipelines of a Certain Age
Retrofitting the cathodic protection system with supplemental anodes would only make sense if the
line in question is very old and the required additional life were significant. The cost to perform a
pipeline cathodic protection inspection will run anywhere from $2,000 to $6,000 per mile, and that
cost may be eliminated if the decision to retrofit is made. There will only need to be a post-
installation survey, once the new anodes are laid.
PIPELINE PROTECTION TECHNIQUES ADOPTED IN GULF OF
MEXICO
Protection of pipelines in order to protect it from corrosion followed by the spilling of Oil into the
sea.
Data :
 24000 miles of till date (2013)
 Total active and heavy duty pipelines
Here the pie chart is showing the laying of pipelines that have been done over the years …
Some 1,222 miles are over 30 years old, and 5,952 miles have celebrated a 20th anniversary.
Obviously these 5,000-plus miles of pipe would be considered at higher risk from an integrity
standpoint than the 11,000 miles younger than 20. The mere fact that these old lines are still in
operation reflects well on the skills of the corrosion control community.

Prime threat: Corrosion
Cause: High sulphide content and other salts in marine water and high bacterial activity on the sea
bed.
All offshore pipelines are protected from seawater corrosion in the same way. The primary
corrosion control system is pipeline coating. This is supplemented with cathodic protection (CP) to
provide protection at coating defects or "holidays." In the Gulf of Mexico, the pipeline coatings
used until the early to mid-1970s were either asphaltic/aggregate, "Somastic"-type, coatings or hot-
applied coal tar enamels. Since then, the trend has been to use fusion-bonded epoxy powder
coatings. In the earlier days, the trend in cathodic protection (CP) was to rely on impressed-current
systems. In the 1960s and early 1970s, zinc bracelet anodes attached to the pipe were widely used.
Since then, more efficient aluminium alloys have surpassed zinc as the preferred material for
offshore galvanic anodes. There are, however, still some operators using impressed current systems
and some using zinc anodes.
Risks Involved:
On pipelines in excess of 30 years old, the risks are quite high. If the cathodic protection systems
have depleted, then corrosion will begin at numerous sites all over the pipeline. Unless detected and
retrofitted, the first leak could be the end of the pipeline, as the next several hundred won't be far
behind. There are only so many clamps that an operator can afford to install before economic
concerns dictate pipeline replacement or abandonment. Given the cost of laying pipelines offshore
today, many of the lines will never be replaced, and this could result in early deaths of the oil and
gas fields they service. Other old lines are the critical links between the new deep water fields and
the shore-based markets. Loss of these lines will present an interesting and unenviable dilemma for
operators.
When considering the role of cathodic protection (CP) in pipeline integrity we should investigate
what causes offshore pipelines to fail and leak. If all the failures of pipelines in the Gulf of Mexico
were counted and tabulated, the findings would probably show the general trend expressed in the
below 2 figures.
Causes of offshore pipeline failure

Causes of offshore riser failure
Since external corrosion is only responsible for a very few of the documented pipeline failures, we
could truthfully say that, in general, the combination of Cathodic Protection (CP) and coatings is
doing a good job.
However, we must not be led into a false sense of security. The only reason the external leaks have
not started in earnest is that the old systems were unknowingly over-designed. Thus, a 25-year
design life has effectively turned into 30, 35 or even 40 years.
There is a practical limit on how long sacrificial anodes will last, and it is based on the auto-
corrosion rate of the anode material. If we were to assume that pipeline systems are all good for at
least 30 years, then there should be several thousand miles of pipeline with depleted CP systems .
The question, then, is why are we not seeing more external failures?
In truth, the answer to that question is that we probably are seeing a higher external corrosion leak
rate than we have at any time in the past. But when will it peak? The pitting rate of steel in seawater
on a well-coated pipeline in the absence of cathodic protection anodes could vary between 0.01-
0.05 inches per year. Thus, it could take anywhere from 5 to 25 years to pit through an inch of steel.
This amount of loss could be sufficient to cause a pipeline failure. Higher corrosion rates can be
generally expected when the pipe coating has a combination of large damaged areas and adjacent
pinhole defects, and when the pipe is exposed to seawater rather than mud. There is also a particular
risk of micro-biologically influenced corrosion (MIC) on buried lines with bitumastic-type coatings
and depleted cathodic protection.

Pipelines how they are designed for their purpose:
9. Design life required - (minimum is 20 years)
10. Pipe diameter length and to-from information
11. Geographic location
12. Type of coating
13. Pipe-lay / installation method
14. Water depth
15. Burial method
16. Product temperature
17. Electrical isolation from platforms or other pipelines

CONCLUSIVE REMEDY: CATHODIC PROTECTION
Close-interval cathodic protection surveys are the most logical strategy, but strangely enough,
operators in the Gulf of Mexico survey very little. When a survey is actually run, it is usually of
little value because the method used (trailing wire) inherently produces erroneous data.
There are accurate survey systems available; these either involve physically contacting the line at
intervals or utilizing remotely operated vehicles (ROV's) to track the pipeline and carry reference
electrode arrays above the pipeline at known locations. This type of survey will let the operator see
the condition of the line and make informed decisions regarding retrofitting.
REFERENCES
 Prediction Of Rate And Volume Of Oil Spill In Horizontal And Inclined
Pipelines
Samuel O Salufu, SPE, University of Ibadan; and Samson O Ibukun, SPE, Laser
Engineering and Resources Consultant Limited
 Pipeline Failure Offshore California: Effective Oil Spill Response in an Environmentally
Sensitive and Politically Charged Area
David J. Rose, Torch Operating Company
 Pipeline Failure Offshore California: Effective Oil Spill Response in an Environmentally
Sensitive and Politically Charged Area
David J. Rose, Torch Operating Company
 Application of a Method to Oil Spill Risk Assessment From Pipeline Failures
M.P. Sharma,* B. Kim, and H.G. Harris,* U. of Wyoming
 ON SHORE OIL SPILL CONTINGENCY PLAN: A KEY ISSUE IN ENI
E&P–UGIT OIL SPILL MANAGEMENT IN ITALY
M. Naldi, ENI E & P SAOP, W. Palozzo, A. Palozzo Proger S.p.A.
 Indian West Coast Oil Spills: A Remedial Preparedness
Surinder Kapoor and H.S. Rawat, * Oil & Natural Gas Commission
 www.mms.gov
 www.nws.noaa.gov

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