EOR-IOR Developmen Plans

1. Reservoir Development Plans,
EOR,Screening,Timing & FieldCase
Reservoir development plans (RDP) and dynamic
management
Improved/Enhanced Oil Recovery (IOR /EOR) – Definitions
– Current Limits
IOR/EOR Basic concepts about Screening and timing
Soft (“non technical) issues. Decision analysis
Reference to Performance predictions

2. Example of Main Stages of Reservoir
Development (Field Development Plan)

3. > EOR method can be initiated at any stage of
production to improve recovery efficiency.
Some reasons to do this are :
* Legal: Regulatory authorities enforce keeping reservoir
pressure above the bubble point (resource anagement)
* Technical: Oil sands or cold/shallow extra heavy oil
reservoirs which will not flow in natural conditions requiring
the implementation of thermal methods as primary
methods.
* Cash Flow : It will be improved if will obtain the higher
production during first years.
Timing of Recovery Processes (RDP)

4. It is a common fact that RDP change or need to be
modified during the production life of the field
- Lack of : reservoir characterization and understanding
of the reservoir at early stages of development
(reduction of uncertainties with time).
- Poor production performance (below expectations)
- Environmental constraints (i.e., CO2 storage , offshore
operations)
- Economics (low oil prices)
- New technologies (i.e., horizontal wells, multilaterals,
new recovery processes, etc)
Dynamics of Reservoir Development Plans

5. Each reservoir has its own characteristics and needs to be
developed considering multiple reservoir variables, for
example reservoir pressure:
- Bubble point pressure (impact on recovery efficiencies)
- Onset for asphaltene deposition/flocculation (impact on
reservoir performance, injectivity and well productivity)
- Retrograde condensation (Typical on gas/condensate
fields)
- Sand production and wellbore stability (sand
production, associated problems and well bore collapse)
Dynamics of Reservoir Development Plans

6. Options for Recovery Methods (I)

7. Options for Recovery Methods (II)

8. IOR & EOR Definitions
IOR

9. IOR/EOR Definitions : SPE E&P Glossary
Improved Oil Recovery (IOR), is “any of various
methods, mainly reservoir drive mechanisms and
enhanced recovery techniques, designed to improve
the flow of hydrocarbons from the reservoir to the
wellbore or to recover more oil after the primary and
secondary methods (water- and gas floods) are
uneconomic.”
Primary Oil Recovery is “the amount of the reserves
recovered by primary production without injected fluid
pressure support”,
Secondary Oil Recovery is “a recovery improvement
process such as waterflooding or gasflooding”

10. IOR/EOR Definitions : SPE E&P Glossary
Enhanced Oil Recovery (EOR), is “one or more
processes that seek to improve the recovery of
hydrocarbon from a reservoir after the primary
production phase.” …..
…“To improve sweep efficiency by reducing the
mobility ratio between injected and in-place
fluids”
and/or
“To eliminate or reduce capillary and interfacial
forces to improve displacement efficiency”

11. IOR/EOR Definitions :S PE E&P Glossary
Consolidating definitions a general definition for
EOR is:
A set of production technologies that involve
the injection of energy or fluids to improve oil
recovery at any stage of production with the
purpose of increasing the total recovery
beyond primary or secondary methods
(waterflooding and gas injection)

12. Recovery Methods

13. BY SUNIL KOKAL AND
ABDULAZIZ AL-KAABI
Tecnology vs Maturity – Current R&D limits

14. RDP - Decision Risk Management:
Example for Water Injection Project
An example of a water injection project show some of the
options that need to be evaluated in recovery projects
within a RDP
The decision tree below shows the options identified for
each decision

15. Reservoir development plans require dynamic and
flexible reservoir management strategies to optimize
field production.
Once a recovery project is started under specific well
spacing and operational parameters, it is highly
probable that some areas will show different responses
,requiring changes in the original plan
Production history, well logs, infill drilling, and monitoring
programs are used to continuously update the reservoir
model that is used to support changes in the RDP (i.e.,
changes in well pattern, well conversions, etc.)
Reservoir Management Injection Project (I)

16. Generally, fields are not developed under a single well
pattern or spacing or injection-production rates, etc.
Pattern size and/or well spacing has a direct effect on
recovery performance and may change for different
recovery processes
Horizontal and highly deviated well technologies have
provided changes in the way fields are developed (from
geometric patterns to optimized geological patterns)
One example of optimized geological patterns are
offshore fields that are not developed by conventional
geometrical well patterns
Reservoir Management Injection Project (II)

17. RDP Infill Drilling & Pattern Modification
Figures shows the impact of infill drilling illing on Texas ,
carbonate formations .
Others :
Duri Field (Indonesia) use a
combination of well patterns:
9-spot, 7-spot and 5-spot patterns
(SPE-22995)
The Ruehlermoor Field (Germany) has reported oil increases using
infill drilling and re-entries (SPE-54114)
The Emlichheim Field has been on continuous development plan
Changes horizontal infill drilling and steam flooding (SPE-69707)

18. RDP Infill Drilling & Pattern Modification
El Morgan Kareem Egypt
PR 15% WF 40% IDP 50%
WAG/N2
> 50%
Pressure
close to
Original

19. RDP Infill Drilling & Recovery Strategies

20. Screening and Timing for EOR
EOR technologies should be visualized at early
stages of the reservoir development plan
Screening studies should not be limited to evaluate technical
feasibility of EOR methods.EOR applicability MUST be validated
with available resources (e.g., natural gas, water, CO2)
If EOR evaluation is decided too late (e.g., high levels of depletion
or watered out reservoirs), economics may not justify its
implementation

21. EOR Screening Studies: General Workflow
# Projects

22. EOR Screening Studies: (“Soft Issues”)
non-technical variables generally overlooked
during screening studies :
Availability of injection fluids
Water sources and quality (treatment costs)
Natural gas (e.g., Pressure maintenance, gas
markets)
Availability of water and/or gas for steam
generation
CO2
Sources (Natural vs. Anthropogenic)
Distance of sources (Geographical location)

23. EOR Screening Studies:
Example of Basic Decision Analysis
After (“JUST AFTER”) evaluating soft or non technical
variables that can make a given project not feasible,
spend time analyzing options (“What if analysis”)
Basic decision analysis will help to define a robust project
case that will have higher chances for its approval due to
the multiple option/scenarios considered
(Risk & Uncertainty mitigation from the beginning of the
project
Incorporate and get involved with field operations at
early stages of evaluation, it will help identifying critical
variables for possible EOR implementation

24. EOR Screening Studies:
Example of Basic Decision Analysis
NPV

25. EOR Screening Studies:
Example of Basic Decision Analysis (Cont’d)
NPV

26. Preliminary performance predictions of IOR/EOR processes can
contribute to evaluate the potential of a particular technology in a
give reservoir
Start simple! (Sector or 2D models):
Permeability/transmissibility modification for conformance treatments
(Model must capture thief zone!)
Average values for Chemical EOR (Default values or documented in
the literature)
If numerical models are not available, analytical or conceptual
model (e.g. Dykstra-Parson Grids) approaches are also very helpful to
support screening studies
EOR Screening Perfomance predictions

27. EOR Screening (d) example of basic case
perfomance predictions & evaluation
K range

28. Note
Information presented here were provided by C.
Norman mainly.
Other sources are lebeled in each slide