Top drive method and system for oil production
OwnerElton D. Fowlerinventor
Life of this patent
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Abstract
Described herein are methods and systems for enhanced oil recovery (EOR). The methods and systems are especially suitable for enhancing oil recovery in bottom-water drive producing formations having a gas cap where coning of bottom water is a problem. An external gas such as natural gas is injected into the gas cap. This essentially eliminates the bottom water drive and replaces it with top gas drive. The amount of gas delivered is calculated to replace the volume of oil produced from the well and maintain a constant pressure at the gas-oil interface, which maintains horizontal thrust to the production point and maintains a stable oil-water interface, preventing coning. The methods expand the area of oil recovery.
Claims16
A method of recovering oil from a producing formation in the earth, wherein the producing formation is abutted on top by a gas cap and on bottom by an aquifer, the method comprising:
- providing a production well extending through the producing formation,
- providing a gas injection well extending into the gas cap,
- injecting an external gas into the gas cap via the gas injection well at a controlled rate correlated to oil production such that (i) an injected gas volume at gas-cap conditions replaces the volume of produced oil and (ii) a gas-cap pressure is maintained within a predetermined threshold of an initial gas-cap pressure measured upon completion of the gas injection well, thereby providing sustained top-gas drive and maintaining horizontal hydraulic thrust across the producing formation, and
- producing the oil via the production well at a production rate limited to a reservoir oil-transfer rate to perforations of the production well so as to maintain a stable oil-water interface and prevent bottom-water coning.
Dependencies are inferred from the claim text.