United Arab Emirates University Collage of Engineering Training and Graduation Project Unit

1. United Arab Emirates UniversityCollage of EngineeringTraining and Graduation Project Unit Design a Technique for Investigating the Influence of Initial Oil Saturation on Oil Recovery Using Miscible Flooding Graduation Project I Supervised by : Dr. Shedid A. Shedid December 6th, 2005

2. Team members: 1- Hassan Ali Hussein (200001455 ) 2- Eisa Daban Hamad (980711302 ) 3- Maath Ebrahim Alshehhi (199900386) Examining Committee: Prof. Abdullrazaq Zekri (Department) Dr. Ali Al-Marzouqi (Department) Dr. Walid Al-Shorbagi (Collage)

3. Acknowledgments

4. Contents • Introduction • Background Theory • Methods and Techniques • Lab Experiments • Conclusions and Recommendations

5. Introduction • Definition of the problem • Enhanced Oil Recovery subdivision • Miscible CO2 injection • Objectives

6. Background Theory • Reservoir Rock Properties: • Porosity. • Permeability. • Mobility ratio.

7. Background Theory • Recovery Methods: • Primary Recovery. • Secondary Recovery. • Tertiary Recovery Methods (EOR). • What is the intent of using EOR? • Improve sweep efficiency. • Eliminate or reduce the capillary.

8. Background Theory Sources of CO2 • Natural CO2 deposits: ammonia plants. • Oilfield gas separation facilities. • Natural gas. • The feasibility of getting CO2 depends on: • Nature of the source • Its location relative to the oilfield • Method of transportation

9. Background Theory • CO2 Miscible Flooding • When does miscibility exist? • What parameters control miscibility? • What does injected miscible CO2 do? • What is miscibility pressure?

10. Background Theory WAG Process: the process of injecting water and gas alternatively with periods of injection

11. Background Theory • Factors that make CO2 an EOR agent: • Reduces oil viscosity and increases water viscosity. • Swilling of crude oil and reduction in oil density. • Acid effect on carbonate and shaley rocks: • Carbonic acid dissolves the Ca and Mg carbonates. • Preventing the shales from swelling and causing blockage.

12. Background Theory What are the advantages of using CO2 flooding? • Low pressure for achieving dynamic miscibility with CO2 comparing with natural gas, flue gas, or nitrogen. • Reduction in crude oil viscosity. • Swelling of crude oil and reduction in oil density. • Availability of CO2 as a potential source.

13. Background Theory What are the disadvantages of using CO2 flooding? • CO2 is a costly fluid, project designs usually have called injection of an optimum volume or slug. • Displacement of CO2 by water is immiscible and a residual CO2 saturation is left in the reservoir.

14. Background Theory • CO2 Flood environmental, health, and safety planning

15. Background Theory • Economicalstudy

16. Methods and Techniques • Case Study • Location: One of Malaysia reservoirs, Dulang B field. • Objectives: • To investigate the effect of CO2 miscible flooding on oil recovery. • To prove if Dulang B crude oil could be extracted by CO2 vaporization. • 1 billion barrel additional crude oil. Therefore, • Reserves will growth • Reservoir life will extends

17. Methods and Techniques Evaluation of CO2 gas injection • The swelling factor increases with CO2 content and pressure. • Density of the liquid phase at saturation decreases with increasing CO2 concentration in the mixture. • Fluid volume increases by 5% at current reservoir pressure of 1400 psig.

18. Methods and Techniques Evaluation Vaporization study of CO2 Gas Injection

19. Methods and Techniques • CO2 swelled oil - oil shrunk as CO2 extracted HC - Vapor phase forms. • 15.92 cc liquid condensate was produced out of 105.19 cc STO (15.14% of the STOOIP). • That was obtained after 1545 cc of CO2 was injected. • One STB of condensate was generated for every 81,400 scf of CO2 injected. • Increasing the amount of CO2 injected, liquid densities slightly increased indicating that the residual liquid was getting denser.

20. Methods and Techniques

21. Methods and Techniques Determination of Minimum Miscibility Pressure • What is MMP? • Why it is important to determine MMP ? • Slim-tube Specifications: • Internal diameter. 0.12 in • Length 60 ft • Packing material sand • Displacement Velocity 54 ft/d

22. Slim- tube Apparatus

23. Methods and Techniques - Parameters calculated. • The volume of CO2 injected. • Volume of sample displaced. • MMP.

24. Methods and Techniques • The recovery was then calculated as the percentage of the oil produced at CO2 breakthrough. • Intersection of miscible and immiscible lines.

25. Methods and Techniques

26. Methods and Techniques

27. Methods and Techniques • MMP = 2875 psig which is about 1000 psig higher than Pi. • The process in the field will therefore be immiscible. • Ruling out the possibility of miscible or even near-miscible CO2 gas displacement process. • CO2 was capable of extracting components heavier than C7+.

28. Lab Experiments • Reservoir Rock Properties • Porosity • Procedures: • Dry weight • Evacuate sample • Immersed sample in saline • Saturated weight • Pore and Bulk volume

30. Lab Experiments • Reservoir Rock Properties • Permeability • Procedures: • Water was added to the accumulator • The core was fixed into the core holder

31. Lab Experiments • Upstream and downstream pressure • Volume of collected fluid • Time • Plot flow rate against pressure drop

32. Lab Experiments Sample 2000B

33. Lab Experiments

34. Conclusions & Recommendations Based upon the achieved comprehensive literature review of CO2 miscible flooding process, the following conclusions are drawn: • Laboratory as well as field results showed that the process of CO2 has recovered incremental oil as a miscible displacement. • Miscibility, oil swelling and oil viscosity reduction are the most important parameters in carbon dioxide flooding. • The results also reveal that CO2 was able to extract and displace several components heavier than C7+.

35. Conclusions & Recommendations • The major factors influence the success of CO2 miscible displacement process include: - Mobility ratio - Remaining oil saturation - Reservoir heterogeneity - Reservoir wettability - Pressure - Temperature - Oil composition

36. Conclusions & Recommendations • The design of CO2 successful project requires accurate calculation of minimum miscibility pressure (MMP) and good description of reservoir rock characteristics.

37. Conclusions & Recommendations • Use actual core samples to conduct the second phase of the project. • The existence of cheap source of carbon dioxide is a key factor to design a successful carbon dioxide projects. • Environmental protection and concern are heavily important as well as good design of the carbon dioxide projects.

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