Downhole Artificial Lift Compressor for Improving Unconventional Oil and Gas Recovery

Abstract

A high-speed downhole motor-driven artificial-lift gas compressor assembly comprising an aerodynamic, gas-bearing supported, multi-stage centrifugal compressor is deployed downhole to work with other components such as electric submersible pumps and separators disposed in a multizone reservoir. Water may be injected into an injection water zone and hydrocarbons allowed to escape from a hydrocarbon producing zone to the surface. Compressed gas may be introduced into an annulus between a casing and tubing and directed into an injection gas zone. In addition, gas being produced in the hydrocarbon producing zone may flow back through the annulus between the casing and tubing or through one or more water separators and/or gas separators into the high-speed downhole motor-driven artificial-lift gas compressor assembly and, once compressed, exit the high-speed downhole motor-driven artificial-lift gas compressor assembly and routed back to the injection gas zone. Thus, water and gas may be separated from the fluid flows and injected back downhole or, alternatively, water may be separated from the fluid flows and hydrocarbons such as oil and/or gas allowed to flow to the surface.

We claim: 
     
         1 . A high-speed downhole motor-driven artificial-lift gas compressor assembly, comprising
 a. a housing;   b. an aerodynamic, gas-bearing supported, multi-stage centrifugal compressor comprising a predetermined set of gas film bearings disposed at least partially within the housing, the aerodynamic design configured to ensure that the compressor achieves a predetermined set of head rise and flow characteristics desired at a target operating point; and   c. a high-speed electric motor drive disposed at least partially within the housing and operatively connected to the aerodynamically designed, gas-bearing supported, multi-stage centrifugal compressor.   
     
     
         2 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the compressor comprises between 2 and 4 compression stages. 
     
     
         3 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the compression stages operate at around 40000 to around 120000 rpm. 
     
     
         4 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the compressor comprises an impeller. 
     
     
         5 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 4 , wherein the impeller comprises an impeller tip having a diameter of between around 65 mm to around 68 mm. 
     
     
         6 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the aerodynamic design comprises a 0-D or a 1-D impeller design. 
     
     
         7 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the aerodynamic design further comprises:
 a. a diffuser geometry;   b. an inlet guide vane (IGV); and   c. a collector.   
     
     
         8 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the housing is further configured to be deployable within a casing comprising an inner diameter of around 3.5 inches to around 4.5 inches. 
     
     
         9 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the high-speed electric motor comprises a plurality of 2-pole motors arranged in series. 
     
     
         10 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the aerodynamically designed, gas-bearing supported, multi-stage centrifugal compressor comprises a turbine. 
     
     
         11 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 10 , wherein the turbine comprises a hybrid gas turbine comprising a heat transfer technology optimized for high cycle efficiency of recuperation, intercooling, or turbine blade cooling over a range of operating conditions typical of a load following demand at a compressor station. 
     
     
         12 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the compressor is configured to be powered with a turbo charger powered with a high-pressure gas source. 
     
     
         13 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the reservoir comprises a conventional reservoir or an unconventional reservoir. 
     
     
         14 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the reservoir comprises a gas reservoir, a gas condensate reservoir, or an oil reservoir with associated gas production. 
     
     
         15 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 1 , wherein the high-speed downhole motor-driven artificial-lift gas compressor is adapted to be used in conjunction with a downhole separator and an Electrical Submersible Pump (ESP) configured to reduce gas blockage or gas lockout and improve efficiency. 
     
     
         16 . The high-speed downhole motor-driven artificial-lift gas compressor assembly of  claim 15 , wherein the high-speed downhole motor-driven artificial-lift gas compressor is further adapted to allow the ESP to be effectively operated in a hydrocarbon well with gas production through a predetermined set of ranges of gas oil ratio. 
     
     
         17 . A method of lifting a hydrocarbon from a hydrocarbon well using a high-speed downhole motor-driven artificial-lift gas compressor assembly comprising a housing, an aerodynamic, gas-bearing supported, multi-stage centrifugal compressor comprising a predetermined set of gas film bearings disposed at least partially within the housing, the aerodynamic design configured to ensure that the compressor achieves a predetermined set of head rise and flow characteristics desired at a target operating point, and a high-speed electric motor drive disposed at least partially within the housing and operatively connected to the aerodynamically designed, gas-bearing supported, multi-stage centrifugal compressor, the method comprising:
 a. deploying the high-speed downhole motor-driven artificial-lift gas compressor assembly in a hydrocarbon well;   b. using the high-speed downhole motor-driven artificial-lift gas compressor assembly to reduce pressure in a reservoir exposed to the hydrocarbon well; and   c. allowing the hydrocarbon to flow from the reservoir to the surface at the reduced pressure.   
     
     
         18 . The method of  claim 17 , further, wherein the high-speed downhole motor-driven artificial-lift gas compressor assembly is deployed within a casing. 
     
     
         19 . The method of  claim 17 , further comprising:
 a. deploying an electric submersible pump (ESP) in the hydrocarbon well;   b. operatively connecting the ESP to the high-speed downhole motor-driven artificial-lift gas compressor assembly; and   c. using the ESP to aid with recovery of hydrocarbons from the hydrocarbon well.   
     
     
         20 . The method of  claim 19 , further comprising:
 a. reconfiguring the high-speed downhole motor-driven artificial-lift gas compressor assembly with a gas and water separator;   b. deploying an electric submersible pump (ESP);   c. using the ESP to inject water downhole into a water zone or waterflood zones to increase production and reserves.   
     
     
         21 . The method of  claim 19 , further comprising:
 a. for areas where gas sales are not available, reconfiguring the high-speed downhole motor-driven artificial-lift gas compressor assembly with a gas and water separator;   b. deploying an electric submersible pump (ESP);   c. using the ESP to inject both water and gas downhole.