Download - Steam Cycling Pre masters Pres
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Cyclic Steam InjectionPresented by
Ahmed Hassan Shehata
Kareem Ahmed Gamal El-Din Moussa
Mahmoud Hussein Mohamed Aboulfotouh
Mohannad Mostafa
Mostafa Ahmed Mostafa Mohamed Ragab
Omar Ahmed Badr El-Din
Omar El-Toukhy
Taher El-Moataz Bellah Abdel Salam Farghaly
Cairo UniversityFaculty of engineeringCairo University-MPM-Engineering Dept.Enhanced Oil recovery
Presented to: Dr. Sayed El-Tayeb. Dr. Mahmoud Abo Elella.
Cairo University-MPM Engineering Dept.
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Agenda1- Introduction.
2- Cyclic steam injection.
3- Mechanism of action.
4- Cyclic steam results.
5- Design Process & Computations.
6- Screening criteria
7- New advances.
8- Conclusion.
9- References.
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Introduction
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What is cyclic steam ?
1. It is a single well operation.
2. Steam is injected in producer well.
3. Steam is left to soak for a period.
4. Well is returned on production with more recovery.
Even if the oil is not heated efficiently at all, increased production can result through the removal of skin damage and cleaning of the tubing string.
N.B. also called: steam soak, steam stimulation, or huff and puff.
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Mechanism of Action
1. Reduction in the oil viscosity In-Situ.
When Oil Viscosity decreases the displacement efficiency increases, Since the water-oil mobility ratio is decreased and oil mobility ratio is increased.
M =
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Mechanism of Action
2- Reducing residual oil saturation, improving oil relative permeability. When oil relative permeability increase ,the water oil mobility ratio decrease ,and the sweep efficiency increase.
M =
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Mechanism of Action
3- Oil swelling ,Increasing FVF
and Vaporizing and distilling condensable
hydrocarbon from the crude.
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Mechanism of Action
4- Sometimes , the cyclic steam injection
in shallow reservoirs with thick
productive zone or high dip with high
lateral permeability results in a high oil
recovery. In these cases the steam cycles
repeated at the beginning
(in closely spaced wells) transmit the
heat through the oil beyond the
normal drainage area of the well.
In this figure , cyclic steam stimulated
Producers With drainage area overlapped and
gravitational effect in place.
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Cyclic steam results
1. Increase the ultimate recovery factor and Stimulate the formation to
produce at higher rate.
Typically 10-20% recovery is obtained
2. Increase the displacement efficiency. Since the water-oil mobility ratio is
decreased and oil mobility ratio is increased.
3. thermal expansion of the oil takes place and the heated oil increases in
volume so that the residual oil saturation is reduced.
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Cyclic steam results
4. Efficiency peaks in early stages and becomes redundant with time.
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Design Process and Computations
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Generic Optimization Guidelines
Evaluate and quantify thermodynamic requirements.
Minimize heat exchange by selecting operating conditions similar to reservoir conditions.
Select high efficiency equipment.
Minimize transportation of hot fluids.
Design Process & Computations
Heat Transfer
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Governing Heat Loss Equations
Surface Pipes Heat Losses:
Wellbore Heat Losses:
Design Process & Computations
Heat Transfer
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Heat Losses:
Special completion string to be used
Cement composition revisited
Tubing design
Thermal packers
Tuning insulation
Casing stress
Design Process & ComputationsHeat Transfer and oil PVT
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Effect of Heat on Reservoir Properties
Temperature increase causes thermal expansion in sand grains and sand structure.
Pore volume expansion affect permeability, which affect water and hydrocarbon mobility.
Confining stresses decrease due to increase in volumes, which causes hydrocarbon unloading.
Design Process & ComputationsHeat Transfer and oil PVT
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Know oil API and composition.
Compute heat capacity of fluid-saturated rock
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Two thirds of injected heat is lost to grains.
Nearby formations will be heated pending on thermal conductivities
Design Process & ComputationsHeat Transfer and oil PVT
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Heat Losses
Adjacent formations
As advancing in formation
Design Process & ComputationsHeat Transfer and oil PVT
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SOR computation:
Special Core Experiment (Thermal Flood Experiment)
- Heated core handler
- Steam with known quality injected to core with existing saturations
- Condensates are measured
- Vaporized water/oil measured
- Measuring extracted fluids volumes in + and P (i.e. injection production)
Design Process & Computations
Rock Properties Alteration SOR
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Water-Oil Relative permeability alteration
Design Process & Computations
Rock Properties Alteration SOR
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 1
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Kro Krw
Before After
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SOR:
Quantity of PV injected to completely displace oil
Repeat process with different steam qualities, recording:
- relative permeability vs. water saturation
- PV injected vs. oil extracted
- volumes of water condensate
- Thermal Efficiency
Design Process & Computations
Rock Properties Alteration SOR
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Well Model on ECLIPSE
Design Process & Computations
Rock Properties Alteration SOR
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Source of water and steam
Facilities sizing
Combined purpose facilities
Thermal/Power efficiencies
QC of steam
Reservoir management at abandonment
Design Process & ComputationsSteam Preparation
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Design Process & Computations
Steam Preparation
Steam Properties:
Steam quality:
X=
, near 0.8 is optimum.
Saturation temperature with respect to Ps and Tref given by:
Ts=a + bPs0.225, where a=0, b=115.1 if T is F and P is psia
where a=-17.8 and b=41.1 if T in C and P in kPa
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Design Process & ComputationsSteam Preparation
Wet Steam Generators
Straight or coil shaped
Nearby water supply
Salinity treatment
Steam quality control
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Dual/Mutual benefit:
Electricity generation in addition to oil recovery
At abandonment, reverse processes can be implemented
- injecting water to heated reservoirs
- hot fluids reproduction
- yielding slightly higher recovery factors
- generating electricity
Design Process & ComputationsSteam Preparation
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Process Efficiencies:
Thermal efficiency; (Q inj-Qlost)/Qinj
Production efficiency; Vo,increment /Vo, do nothing
Volumetric efficiency; Vinj/Vprod
Economic efficiency pre and post abandonment
Design Process & Computations
Steam Preparation
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Screening Criteria
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New Advances
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New Advances
Fracturing With Viscoelastic Surfactant Fluid in Cyclic Steam Injection
Not a case study
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Hydraulic-Fracturing
By fracturing the high-permeability sand-producing formations, two combined
conditions are achieved:
1.The permeability-damaged zone is bypassed
2.Water can dissolve one of the most frequently found cementing materials
3.The fluid velocity is reduced
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Anionic Viscoelastic gels
1. Temporarily creates an inverse emulsion, having a viscosity lower than both the crude oil and the fracturing fluid
2. Viscoelastic fluids dont contain any solids to build viscosity, there is no filter cake damage
3. One of the best carrying fluid for good Proppant transport feature
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Comments
The synergy of two production improvement techniquescyclic steam injection
and hydraulic fracturingresults in improved high-rate production for high-
permeability formations with heavy oil.
Cyclic steam injection, well completion and the stimulation fluid all can create
formation damage in the wellbore. This problem can be addressed a careful
selection of the fracturing fluid.
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Conclusion
To sum up Steam injection a very important steam recovery method. Many field studies and researched are made in order to improve it and make it an effective recovery method.
Also, Steam injection is the most effective enhanced oil recovery process based on the amount of oil produced. Although cyclic steam injection has contributed much to oil production, its future use will be for stimulating and preparing wells for steam flood and in situ combustion.
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References
1- Khairy, M. (2005). Enhanced Oil Recovery. Society Of Petroleum Engineers, 15.
2- Carcoana, A. (1992). Applied Enhanced Oil recovery. New Jersey: Prentice Hall.
3- Lake, L. W. (1989). Enhanced Oil Recovery. New Jersey: Prentice Hall.
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