Reservoir dive mechanisms

Reservoir drive mechanisms

1. Reservoir Dive Mechanisms

2. Group # 2 Group Members Umar Khalid 2013-PET-06 M.Usman Manzoor 2013-PET-05 Ahsan Ali 2013-PET-08 Abdi Aziz Rashid 2013-PET-53 AbdulRahman 2013-PET-07

3. Discussion Outline Definition of Reservoir Drive Mechanism Types of Reservoir Drive Mechanisms Primary Recovery Drive Mechanisms in Primary Recovery Secondary Recovery & its Drive Mechanisms Tertiary Recovery(EOR) & its Mechanisms Infill Recovery References Overview Queries

4. Reservoir Drive Mechanism Recovery of hydrocarbons from Petroleum/oil reservoir. It supplies energy that moves the hydrocarbons located in a reservoir toward the wellbore as fluid is removed near the wellbore.

5. Types of Reservoir Drive Mechanism Recovery of hydrocarbons from an oil reservoir is commonly recognized to occur in several recovery stages .We use different mechanisms in these stages.These are : Primary recovery Secondary recovery Tertiary recovery (Enhanced Oil Recovery, EOR) Infill recovery

6. Primary Recovery Natural energy of the reservoir works as Drive Expansion of original reservoir fluids Natural energy is determined by Production data (Reservoir Pressure and Fluid production Ratios) Use of the pressure already in the reservoir

7. Drive Mechanisms in Primary Recovery Solution Gas Drive Gas Cap Drive Water Drive Gravity drainage Combination or Mixed Drive

8. Solution Gas Drive Mechanism Reservoir rock surrounded by impermeable barrier. At the start of Production, expansion of dissolved gases occur. Change in fluid volume results in production of Reservoir fluids. A solution gas drive reservoir is initially either considered to be Under saturated Saturated

9. Solution Gas Drive Mechanism

10. Oil Recovery from Solution Gas Drive Reservoirs Initial reservoir pressure bubble point pressure 0 5 10 15 reservoir pressure (psig) Dissolved gas reservoirs typically recover between 5 and 25% OIIP and 60 to 80% GIIP. Oil recovery ,% of OOIP

11. Gas Cap Drive Expansion of already present Gas Cap above the reservoir . Decrease in pressure during the production, expansion of Gas cap occur. As production continues, the gas cap expands pushing the gas-oil contact (GOC) downwards. Better than Solution gas drive . The recovery of gas cap reservoirs is better than for solution drive reservoirs (20% to 40% OOIP).

12. Gas cap Drive

13. Water Drive Mechanism Reservoir bounded by aquifers. During Pressure Depletion, the compressed water expands and overflow towards reservoir. Invading water drive the oil towards producing wells. Water influx acts to mitigate the Pressure Decline. The recovery from water driven reservoirs is usually good (20-60% OOIP) Oil recovery from water drive reservoirs typically ranges from 35 to 75% of the original oil in place

14. Water Drive Mechanism

15. Gravity Drainage Density Differences segregate oil, water and gas . Relatively weak mechanism Can be used as drive mechanism in combination with other drive mechanism The best conditions for gravity drainage are: Thick oil zones. High vertical permeabilities Rate of production generated by gravity mechanism is vey low( 50-70% OOIP). The rate of oil gravity drainage in the reservoir is usually low compared to field production rates.

16. Gravity Drainage

17. Combination or Mixed Drive In practice, reservoir usually incorporates at least two main drive mechanisms. The management of the reservoir for different drive mechanisms can be diametrically opposed. For example Gas cap & Aquifer are sometime present together. Strength of drives must be identified as early as possible in the life of reservoir to optimize the reservoirs performance.

18. Combination or Mixed Drive

19. Secondary Recovery Results from human intervention in the reservoir to improve recovery after the low efficiencies of Natural /Primary Drive mechanisms. Two techniques are commonly used : (i) Water flooding (ii) Gas flooding

20. Water Flooding Mechanism Injection of water in the base of reservoir . Water flooding maintain the reservoir pressure. Displace oil (usually with gas and water) towards production wells. The successful outcome depends on Designs based on accurate relative permeability data in both horizontal directions, The choice of a good injector/producer array

21. Water Flooding Mechanism

22. Gas Flooding Mechanism Same as Water Flooding. Injection of a gas. e.g CO 2 , N 2 or flue gases are generally used. Categorized into two types : Immiscible gas injection. Miscible or high-pressure gas injection.

23. Gas Flooding Mechanism I mmiscible gas injection Inefficient fluid for additional oil recovery. The gas is non-wetting to reservoir rocks The gas will move through the larger spaces of the reservoir rock Thus the initial gas may be displacing gas not oil. Miscible gas injection The gas is wetting the reservoir rock. The gas moves through smaller pores. The injection of non aqueous hydrocarbons solvent. The displacement of oil occurs. An important factor is that the mass transfer between displaced and the displacing factor/ phase. Leads to the formation of oil bank, to move.

24. Gas Flooding Mechanism

25. Tertiary Recovery (EOR) Extraction by Primary and Secondary recovery methods is about 35% of the original oil in place. Many methods are used: (i) Thermal (ii) Chemical (iii) Miscible gas

26. Thermal EOR Use of heat to improve oil recovery by reducing the viscosity of heavy oils and vaporising lighter oils and hence improving their mobility. This technique includes : Steam injection injection of a hot gas that combusts with the oil in place. Microwave heating downhole Hot water injection. thermal EOR is probably the most efficient EOR approach.

27. Thermal EOR

28. Chemical EOR Use of Chemicals added to water in the injected fluid of a Waterflood to improve oil recovery. This can be done in many ways, examples are listed below: Increasing water viscosity (polymer floods) Decreasing the relative permeability to water (cross-linked polymer floods) Increasing the relative permeability to oil (micellar and alkaline floods). Decreasing the interfacial tension between the oil and water phases(micellar and alkaline floods)

29. Chemical EOR

30. Miscible Gas U ses a fluid that is miscible with the oil A fluid has a zero interfacial tension with the oil. In practice a gas is used since gases have high mobilities and can easily enter all the pores in the rock providing the gas is miscible in the oil. Three types of gas are commonly used: Carbon di oxide Nitrogen Hydrocarbon gases All of these are relatively cheap to obtain..

31. Miscible Gas

32. Infill Recovery At the end of the reservoir life. To improve the production rate. To carry out infill drilling, Directly accessing oil that may have been left unproduced. By using all the previous natural and artificial drive mechanisms. Infill drilling can involve very significant drilling costs Additional production may not be great.

33. References http://homepages.see.leeds.ac.uk/~earpwjg/PG_EN/CD%20Contents/Formation%20Evaluation%20English/Chapter%203.PDF https://www.metu.edu.tr/~kok/pete110/PETE110_CHAPTER5.pdf http://wiki.aapg.org/Drive_mechanisms_and_recovery Petroleum Reservoir Engineering ----Basic Concepts general view of oil recovery https://www.google.com.pk/slideshare

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