Technique for control of injection wells

• US 4,374,544 A
• Filed: 09/19/1980
• Issued: 02/22/1983
• Est. Priority Date: 09/19/1980
• Status: Expired due to Term

• Current Assignee: Amoco Corporation (BP PLC)
• Original Assignee: Standard Oil Company (BP PLC)
• Inventors: Westerman, Granval W., Otwell, Corbett I.
• Primary Examiner(s): Pate, III, William F.
• Application Number:
  US06/188,631
• Time in Patent Office: 886 Days
• Field of Search: 166/252, 166/66, 166/53, 166/370
• US Class Current: 166/252.4
• CPC Class Codes: E21B 43/12 Methods or apparatus for controlling the flow of the obtained fluid to or in wells E21B43/25 takes precedence; valve arrangements E21B34/00
• CPC Class Codes: E21B 43/16 Enhanced recovery methods for obtaining hydrocarbons

Abstract

An injection well control method and apparatus controls fluid injection rates during secondary or tertiary petroleum recovery operations by monitoring bottomhole pressure adjacent an underground formation receiving the injected fluids while simultaneously adjusting the fluid injection rate to substantially reduce unwanted variations in said bottomhole pressure. The injection controller is further adapted for operation on a solar-powered circuit to eliminate the need for electrical power lines in remote geographical locations.

Claims

1. A method of controlling the injection of a fluid through a wellbore into an underground formation which comprises:

(a) injecting said fluid through said wellbore into said formation;

(b) detecting the pressure of said fluid in said wellbore in the vicinity of said formation; and

(c) using the pressure detected in step (b) to control the rate of injection of said fluid such that the pressure in the wellbore in the vicinity of said formation is maintained within a predetermined range.

2. A method for controlling the rate of injection of fluid into an underground formation comprising:

(a) measuring both the injection rate of fluid into the underground formation and the bottomhole pressure adjacent said formation during the injection of fluid into the underground formation;

(b) calculating the difference between each of said measured quantities and a preset value for each;

(c) comparing the differences calculated in step (b) to determine a control error which is the calculated difference with the larger deviation from its respective preset value;

(d) generating a control signal proportional to said control error;

(e) transmitting said control signal to an injection control valve in the flow line between the injection pump and the injection well; and

(f) operating said valve in response to said control signal to maintain the injection of fluid within a desired range.

3. A method for controlling the rate of injection of fluid into an underground formation comprising:

(a) monitoring both the rate of injection of fluids into said well and the bottomhole pressure in said well in the vicinity of said formation;

(b) comparing the value of said injection rate and said bottomhole pressure to a preset value for each;

(c) operating an injection control valve in response to the comparison made in step (b) so that the valve controls the rate of fluid injection to maintain both the bottomhole pressure and the injection rate near their respective preset values such that the bottomhole pressure in the well in the vicinity of said formation is maintained within a predetermined range.

4. Apparatus for controlling the rate of fluid injection into an underground zone comprising:

(a) measuring means for both the injection rate and the bottomhole pressure in a wellbore adjacent the zone receiving the fluid during said fluid injection;

(b) control error determining means for selecting a control error which is the larger deviation from a preset value of either the bottomhole pressure or injection rate measured by said measuring means;

(c) signal generating means for generation of an electrical signal proportional to the control error determined by said control error determining means;

(d) control means for regulating the rate of fluid injection into said underground formation; and

(e) signal transmitting means for communicating the signal generated by said signal generating means to said control means.

5. A system for controlling the injection rate of a fluid through a wellbore into an underground zone which comprises:

(a) means for injecting said fluid through said wellbore into said zone;

(b) pressure monitoring means for detecting the pressure of said fluid in said wellbore at the level of said underground zone; and

(c) means for controlling the rate of flow of said fluid in response to the pressure detected by said pressure monitoring means such that the bottomhole pressure in the wellbore in the vicinity of said formation is maintained within a predetermined range.