Oil Recovery Methods Overview

Which of the following is NOT a method of primary oil recovery?

Artificial lift
Solution gas drive
Natural flow
Water flooding (correct)

What is the goal of enhanced oil recovery (EOR) methods?

To maintain reservoir pressure using water injection
To extract oil using only natural reservoir energy
To recover only the initial reserves of the reservoir
To reduce the residual oil saturation as low as possible (correct)

Which of the following is NOT a thermal EOR method?

Steam flooding
In-situ combustion
Microbial EOR (correct)
Hot water injection

What is the primary goal of improved oil recovery (IOR) processes?

To improve on the natural recovery process (C) Signup and view all the answers

Which of the following is NOT a non-thermal EOR method?

Steam flooding (B) Signup and view all the answers

What is the primary source of natural reservoir energy for primary oil recovery?

All of the above (D) Signup and view all the answers

In peripheral flooding, the injection wells are located at the:

External boundary of the reservoir (B) Signup and view all the answers

Which of the following is NOT a regular injection pattern?

Crouching (C) Signup and view all the answers

What is the mechanism affecting producing wells in bottom water drive reservoirs?

Coning (B) Signup and view all the answers

In which phenomenon does the oil/water interface become unstable, causing water to 'finger' or 'tongue' up the base of the formation?

Fingering (C) Signup and view all the answers

What is the critical problem area in waterflooding related to the distribution of injected water?

Poor volumetric sweep efficiency (B) Signup and view all the answers

In which phenomenon does encroaching water break through to the producing well before the entire drainage area is swept?

Encroaching water (D) Signup and view all the answers

What is the primary purpose of gas injection in oil reservoirs?

To maintain reservoir pressure (A) Signup and view all the answers

Which of the following is a key problem associated with gas injection into an oil reservoir?

The injected gas tends to channel or finger through the oil, bypassing much of the oil (B) Signup and view all the answers

What is the main difference between gas injection into the gas cap versus gas injection into the oil zone?

Gas injection into the gas cap is more effective for pressure maintenance (D) Signup and view all the answers

Which of the following factors is the LEAST important in determining the success of a gas injection system?

The type of gas being injected (B) Signup and view all the answers

Compared to water injection, what is a key advantage of gas injection for improving oil recovery?

Gas injection can achieve higher sweep efficiency in the reservoir (B) Signup and view all the answers

Which of the following is a key challenge associated with gas injection into an oil reservoir?

The injected gas may be difficult to recombine with the remaining oil in the formation (A) Signup and view all the answers

What is the main advantage of steam drives over hot water floods?

Steam drives work more efficiently in shallow formations due to distillation and reforming. (D) Signup and view all the answers

Why are steam drives usually limited to shallow formations?

Steam condenses to water at deeper depths, reducing efficiency. (A) Signup and view all the answers

What is the purpose of injecting air into the reservoir and burning some oil underground?

To reduce the viscosity of unburned oil and increase production. (D) Signup and view all the answers

What is the role of air injection in recovering heavy oil through combustion processes?

To maintain high reservoir pressure and reduce oil viscosity for increased production. (D) Signup and view all the answers

What is the main difference between forward and reverse combustion techniques?

Forward combustion involves burning oil underground, while reverse combustion involves burning gases above ground. (B) Signup and view all the answers

How does distillation of oil contribute to the efficiency of steam drives?

Distillation strips away lighter components, making oil recovery more effective. (D) Signup and view all the answers

What is the primary objective in selecting the proper pattern for the injection fluid?

To maximize the contact between the injection fluid and the crude oil system (B) Signup and view all the answers

Which of the following is not mentioned as a way to achieve the objective of maximizing contact between the injection fluid and the crude oil system?

Implementing irregular injection patterns (C) Signup and view all the answers

What is the primary reason for irregular injection patterns as mentioned in the text?

To accommodate surface or subsurface topology and/or the use of slant-hole drilling techniques (B) Signup and view all the answers

In the case of marginal economics, how does the text suggest that injection wells may be selected?

By converting only a few production wells into injectors in a non-uniform pattern (C) Signup and view all the answers

What is a potential reason for irregular injection patterns besides surface/subsurface topology and slant-hole drilling?

Faulting and localized variations in porosity or permeability (B) Signup and view all the answers