Theoretical Questions

Production Technology

Note: You will not get exactly these questions during the Final Exam. However, if you answer these questions while preparing for the exam, then you can consider yourself prepared for the “theoretical questions” part of the Exam.

1. What kind of data is included in Diagnostic Plot?

2. What is a primary recovery method?

3. What is a secondary recovery method?

4. What is a natural flow?

5. Types of Artificial Methods?

6. Reservoir drive mechanisms?

7. What kind of parameters are used to estimate STOIIP?

8. What does IPR describe?

9. What kind of information is required to construct IPR plot?

10. What does VLP describe?

11. What kind of information is required to construct VLP plot?

12. What happens if IPR and VLP curves do not intersect?

13. How does viscosity, pressure difference, cross section area and length of a system affect permeability?

14. What is Productivity Index?

15. What’s the difference between Steady State Flow and Semi Steady State Flow?

16. What is a skin factor and what does mean positive/negative skin factor?

17. Perforation objectives?

18. How is shaped charge performance is gauged?

19. What is geosteering during Horizontal well construction and what type of data is required?

20. What is a smart well?

21. What are the benefits of horizontal wells?
Horizontal wells offer the following advantages over those of vertical wells:

• Large volume of the reservoir can be drained by each horizontal well.

• Higher productions from thin pay zones.

• Horizontal wells minimize water and gas zoning problems.

• In high permeability reservoirs, where near-wellbore gas velocities are

high in vertical wells, horizontal wells can be used to reduce near-wellbore

velocities and turbulence.

• In secondary and enhanced oil recovery applications, long horizontal injection wells provide higher injectivity rates.

• The length of the horizontal well can provide contact with multiple fractures and greatly improve productivity.

22. Where pressure losses occur?

23. What is Absolute Open Flow?
The simplest approach to bottom hole completion would be to leave the entire drilled reservoir section open after drilling, as shown in Fig 2. Such completions are sometimes referred to as “barefoot” completions and the technique is widely applied. Since no equipment requires to be installed there are savings in both costs and time. However this type of completion does mean that the entire interval is open to production and hence it often provides no real selective control over fluid production or injection. It is therefore not recommended for production or injection wells where distinctive variations in layeral permeability will detrimentally control the sweep efficiency on zones under water flood or gas injection. Further, in an oil well if water/gas breakthrough or migration into the wellbore occurs it is difficult to isolate unless the entry is at the base of the well where isolation with a cement plug may be successful. The possibility of interzonal cross flow or zonal back pressure dictating multizone depletion cannot be corrected with this type of completion. This lack of zonal control for production or injection is a major limitation on the application of this technique.
Open hole completions should only be applied in consolidated formations as the borehole may become unstable once a drawdown in applied to induce the well to flow. In such cases either total collapse of the formation or the production of sand may occur. Currently open hole completions are applied in a range of environments:
a) Low cost / multi well developments
b) Deep wells, consolidated with depletion drive
c) Naturally fractured reservoirs

d) Some horizontal and multi lateral wells

 

24. What is the purpose of Nodal Analysis?

 

25. What is GOR, WOR, GLR?
GOR - the produced gas-oil ratio (GOR) at any particular time is the ratio of the standard cubic feet of total gas being produced at any time to the stock-tank barrels of oil being produced at that same instant.
WOR is defined as the ratio of the water flow rate to that of the oil. Both rates are expressed in stock-tank barrels per day.
GLR

 

26. What is a dew point pressure and bubble point pressure?
The dew-point pressure pd of a hydrocarbon system is defined as the pressure at which an infinitesimal quantity of liquid is in equilibrium with a large quantity of gas. For a total of 1 lb-mol of a hydrocarbon mixture, i.e., n = 1, the following conditions are applied at the dew-point pressure: nL = 0, nv = 1
Bubble point:At the bubble point pb the hydrocarbon system is essentially liquid, except for an infinitesimal amount of vapor. For a total of 1 lb-mol of the hydrocarbon mixture, the following conditions are applied at the bubblepoint pressure: nL = 1 nv = 0

 

27. What is Oil FVF?
Oil formation volume factor is defined as the ratio of the volume of oil at reservoir (in-situ) conditions to that at stock tank (surface) conditions. This factor, is used to convert the flow rate of oil (at stock tank conditions) to reservoir conditions. It is defined as:

28. What are the advantages of Hydraulic pumps?

29. What are the disadvantages of Hydraulic pumps?

30. What’s the principle of gas lift method?
gas lift - the process of raising or lifting fluid from a well by injecting gas down the well through tubing or through the tubing-casing annulus. Injected gas aerates the fluid to make it exert less pressure than the formation does; the resulting higher formation pressure forces the fluid out of the wellbore. Gas may be injected continuously or intermittently, depending on the producing characteristics of the well and the arrangement of the gas-lift equipment.

или можете написать: The gas bubbles rise through the tubing and entrain the liquid. Since the density of a gas-oil mixture is lower than the hydrostatic pressure of the gas-oil column is lower and the back pressure on the formation decreases. Therefore, the difference between the formation pressure and the bottom-hole flowing pressure causes oil to flow from the pay zone bed into the well.

 

31. Gas lift advantages?

32. Gas lift disadvantages?

33. Gas lift design parameters?

34. Gas lift valves?

35. If water cut increases how does VLP curve change?

36. What is the difference between continuous and intermittent gas lift methods?

37. ESP downhole equipment and their properties?

38. ESP surface equipment and their properties?

39. ESP advantages?

40. ESP disadvantages?

41. ESP motors?

42. PCP principle?

43. PCP advantages?

44. PCP disadvantages?

45. The principle of sucker pump?

46. Sucker pump failure reasons?

47. What is dynamometer used for in Rod Pumps?

48. Rod pumping advantages?

49. Rod pumping disadvantages?

50. Rod pump rate is dependent on what parameters?

51. What is formation damage?

52. What does Skin Total include?

53. Hawkings equation of Formation Damage?

54. Sources of Formation Damage?

55. Formation damage due to fluid loss?

56. Relative permeability principle?

57. What does happen to relative permeability to oil and to water, if water saturation increases?

58. What is a capillary pressure?

59. What’s the purpose of well stimulation?

60. What stimulation techniques are available and their objective?

61. Minimum matrix stimulation candidate well selection criteria?

62. The stimulation cycle?

63. Potential formation damage caused by Matrix Stimulation?

64. Matrix stimulation – laboratory testing?

65. Matrix stimulation – bullhead or treatment via coiled tubing?

66. What kind of information can be obtained from Well Testing?

67. What kind of information can be obtained from Production Logging?

68. Minimum requirements for a propped hydraulic fracturing well candidate?

69. Key fracture design issues?

70. What is production system optimization?

71. What are the bottom hole completion techniques and what's the difference among them?

72. What are the flow conduit between the reservoir and surface and what's the difference among them?