Well intregrity

1. Well Integrity Management
28 May, 2021
Management
Integrity
Well

2. Discussion Outline
 Well Integrity
 Well Integrity - Failures
 Well Integrity Management
 Integrity In Well Designing
 Well Completion
 Well Barriers
 Consequences of Integrity Failures
 Casing Pressure
 Various Standards on Well Integrity
 Few Examples of Integrity Failures

3.  Integrity is defined as“The quality of being honest and having strong
moral principles” and “The state of being united or undivided” by Oxford.
 Well integrity, in regard to oil wells, is defined by NORSOK D-010 as the
“Application of technical, operational and organizational solutions to
reduce risk of uncontrolled release of formation fluids throughout the life
cycle of a well”
Well Integrity ?
Well integrity is the quality or condition of a well being structurally sound.

4. Well Integrity – a major issue
Well integrity problems are seriously facing the oil and gas industry worldwide. For example,
45%, 34%, and 18% of the wells in Gulf of Mexico, North Sea UK, and North Sea Norway,
respectively are suffering from well integrity failures (Decoworld, 2014).
According to the Society of Petroleum Engineers (SPE, 2016), over the next decade, the oil
industry will drill more wells than they have in the last 100 years and that of the world's
current inventory of 1.8 million wells, roughly 35% have integrity problems
(Viableopposition, 2013).
In the Middle East, over 50% of all wells have integrity issues with 10-15% of these being
critical (Well Integrity Conference, 2015).
Furthermore, the rise in extended reach wells and other high risk characteristics, such as
HP/HT wells, shale formations, corrosion, scale, and sour service fields in the Middle East,
are increasing the spotlight on well integrity.

5. Well Integrity Failures

6. Casing Pressures
Sources of annulus pressure– cement failure ???
Applied pressure
Thermal induced pressures
• - Thermal expansion of fluid
• - Dissolved gas evolution from annulus fluid
Ballooning of adjacent annuli
 Sustained annulus pressure
• - Barrier failure
• - Poor design
• - Unforeseen source of pressure

7. Regulations on Casing Pressure
 ISO defines Maximum Allowable Annular Surface Pressure (MAASP) as the
lowest of the calculated strength cases
 Operator decides Max operating pressure (MOP) as % of MAASP
 ISO gives guideline that MOP should not exceed 80% MAASP
 API RP90 does not recognise MAASP – instead talks about Max allowable
operating pressure (MAWOP)
 API RP 90 defines annulus MAWOP as:
• 50% of the MIYP of the casing being evaluated or
• 80% of the MIYP of the next outer casing
• 75% of the MCP of the inner tubular pipe body
• For the outer most pressure containing casing MAWOP can not exceed 30%
of it’s MIYP

8. Acceptable Annulus Pressure
Acceptable Pressure / Leak Rate Determination
Wells with <100 psig annulus pressure should be monitored only.
Wells with >100 psig but < MAWOP if they can be bled to zero
within 24hr presents an acceptable risk
 Wells with annulus pressure above MAWOP or where the pressure
cant be bled off must be dealt with on a case by case basis.

9. Managing Annulus Pressures
Annulus Pressure bleed off system is used but in most of the cases.
What if there is lack of access to annulus?
 This occurs in subsea wellheads
 Leave the shoe open to allow for bleed off
Rupture disks to provide leak points in the casing
 Nitrogen foamed spacers to provide a gas cap
 Include compressible beads in the annular fluid
 Collapsible foam wrap on casing – controlled collapse
 Vacuum insulated tubing (reduce heat transfer)

10. Threats to well integrity – Material degradation & loss
of functionality
Corrosion (well fluids)
• Sweet
• Sour
• Oxygen
• Cathodic
External casing corrosion
Erosion / Casing wear
Sand production
Elastomer degradation
Fatigue and tubing & casing stress (pressure, thermal, tectonic)
Scale formation (e.g. BaSO4, CaCO3)
 Hydrate formation

11. Why Well Integrity Management

12. Phases of well Integrity Management
Well design Phase,
Well construction Phase,
Well integrity monitoring Phase,
Well abandonment Phase .
 Well integrity management is an art of
managing the well to reduce risk applying
technical, operational and organizational and
can be divided into four distinct Phases.

13. Well Completion Design
Factors Affecting Well Completion Design
Lithological
Reservoir parameters
Producing Fluid Properties
Mode of production
Metallurgical
Environmental
Statutory
Completion Drives the Bus.
Complete for Future

14. Pre trials and NASS Execution
Completion Engineer ?
Who is the Completions Engineer?
• It’s the person who picks perfs
• The stimulation requirements are predetermined
• Well bore stability from rock properties
• Flow rates stimulated and unstimulated
• Withdrawal points considering compartments and barriers
• Tubular requirements
• Determines hole stability
• Determines cased and cemented liner
• Decides well must be frac’d
• Determines how the well will be pumped- back pr./ Max. drawdown

15. Basis of Design
 Gas or oil well?
 Flowing well or artificial lift required
 Reservoir Bottom Hole Pressure is KEY!
 You need confidence in BHP (fluid level)
measurements!
 Estimate your anticipated production rates.
 Tubing size dictates casing/hole size, - entire well
design.
 Rock stability while drilling and producing

16. Completion Design Strategy
Completion Strategy
 Open Hole
 Slotted Liner
 Pre-packed Screen
 Gravel Pack
 External Casing Packers
 Cemented Casing
Simple
Complex

17. A Typical Well Completion

18. Well Barrier
Well Barrier (WB): “Envelope of one or several dependent
barrier elements preventing fluids or gases from flowing
unintentionally from the formation, into another formation or
to surface”.
Every well is designed with certain barriers to prevent uncontrolled
hydrocarbon flow to atmosphere
 Integrity of these barriers is essential to ensure safety of the well
 Loss of barriers leads to loss of well integrity

19. Well Barriers
● Capable of sustained flow? - Two
independently tested well
barrier envelopes should be maintained.
● Well barriers are pressure containing
envelopes of one or several Well Barrier
Elements (WBE).
● The primary barrier is exposed to the
source,
● The secondary barrier is the barrier that is
exposed to the source only if the primary
barrier fails
● Two well barriers are independent if any
loss of integrity of one well barrier does not
jeopardize the integrity of the other
Source:
ISO/TS 16530-2

20. Well Barrier
Failures
Source:
ISO/TS 16530-2

21. Consequence of Well Integrity Failure
Potential risk of uncontrolled hydrocarbon flow
leading to
– Environmental damage
– Asset damage
– Loss of multiple lives
– Business disruption
– Recovery cost
– Company’s reputation

22. Standards related to Well Integrity
 API STD 53: Blowout Prevention Equipment System for Drilling, 4th Edition, Jan 2012
 API RP 96: Deepwater Well Design and Construction, 1st Edition, Jan 2013
 NORSOK D-010: Well Integrity in Drilling Well Operations, Revs 4, Jun 2013
 ISO/TS 16530-2: Well integrity for operation phase, 2013
 ISO/DIS 16530-1: Life cycle governance, 2017
 API RECOMMENDED PRACTICE 90: Annular Casing Pressure Management for
Offshore Wells

23. Key to suceddful Welll Integrity Management
● Organisational Competency
● Develop proactive rather than reactive well
integrity management
● Designing for the Life Cycle - Embedding well
integrity in the equipment design
● Solid well construction practices and well life
cycle management
● Management commitment

24. Standards related to Well Integrity
 API STD 53: Blowout Prevention Equipment System for Drilling, 4th Edition, Jan 2012
 API RP 96: Deepwater Well Design and Construction, 1st Edition, Jan 2013
 NORSOK D-010: Well Integrity in Drilling Well Operations, Revs 4, Jun 2013
 ISO/TS 16530-2: Well integrity for operation phase, 2013
 ISO/DIS 16530-1: Life cycle governance, 2017
 API RECOMMENDED PRACTICE 90: Annular Casing Pressure Management for
Offshore Wells

25. Some Examples of Integrity Failures
 Design Phase - ??
Hypothetical Ex. 1 . A 2000 m deep gas well with BHP of 220 kg is perforated in brine of sp gr. 1.12. The well is
temporarily abandoned by setting bottom and upper bridge plugs at 500 m and 1000 m for completion in
future due to lack of down hole equipments. What is expected ?.
Hypothetical Ex 2 . A gas well is subdued by suitable brine. A top cement plug is placed at 100m and well is
worked over for repair of the well head ( obviously without BOP). Is there any risk?
 Construction Phase
1. Mocando Disaster
2. Hypothetical Ex.1.
3. Hypothetical Ex.2 during repair phase.
 Production (Monitoring & Repair) Phase
1. Hypothetical Ex.3 At one well a civil worker observe a drop by drop mud coming out form outer
annulus valve. Inform GGS by evening but the cellar pit if full of mud and night but by day light there is heavy
flow of gas and some water and annulus valve and are mud cut. Reason
 Abandon Phase
1. Hypothetical Ex.1 ( At temporary abandonment)
2. Hypothetical Ex.3 ( Well was ultimately abandoned )

26. Thank You