Two-step artificial lift system and method

Abstract

A two-step artificial lift system and method is proposed which provides for lifting of reservoir fluids without fluid injection using a first step system and lifting of reservoir fluids with fluid injection using a second step system. The second step system reuses the components of the first step system. The system and method aids in lifting reservoir fluids from vertical, deviated, and horizontal wellbores.

What is claimed is: 
     
         1 . An artificial lift system for use in a wellbore extending from a surface to a subterranean reservoir containing reservoir fluids, the system comprising:
 a casing disposed in the wellbore;   a first tubular string disposed in the casing;   an upper bi-flow connector disposed in the first tubular string,   a lower bi-flow connector disposed in the first tubular string below the upper bi-flow connector;   a second tubular string disposed below the lower bi-flow connector and sealingly engaging the lower bi-flow connector, wherein the lower bi-flow connector allows flow between the second tubular string and the annulus between the casing and the first tubular string;   a first fluid displacement device disposed in the first tubular above the upper bi-flow connector, wherein the upper bi-flow connector allows flow between an annulus formed by the casing and the first tubular string and the fluid displacement device; and   a first seating nipple disposed in the first tubular string above the upper bi-flow connector, wherein the fluid displacement device is releaseably connected to the first seating nipple.   
     
     
         2 . The artificial lift system of  claim 1 , wherein said upper bi-flow connector comprises a tubular that contains a center bore in communication with one or more horizontal channel(s) that extend through the width of the device, and one or more vertical channel(s) that extend through the length of the device, and said horizontal channel(s) and said vertical channel(s) do not communicate with-in said bi-flow tool 
     
     
         3 . The artificial lift system of  claim 2 , wherein said center bore extends to the upper end of said upper bi-flow connector but does not extend to the lower end of said upper bi-flow connector 
     
     
         4 . The artificial lift system of  claim 2 , wherein said center bore extends to the upper and lower end of said upper bi-flow connector 
     
     
         5 . The artificial lift system of  claim 1 , wherein said lower bi-flow connector comprises a tubular that contains a center bore in communication with one or more horizontal channel(s) that extend through the width of the device, and one or more vertical channel(s) that extend through the length of the device, and said horizontal channel(s) and said vertical channel(s) do not communicate with-in said bi-flow tool and said center bore extends to the lower end of said tubular but does not extend to the upper end of said tubular 
     
     
         6 . The artificial lift system of  claim 1 , further including one or more casing annular sealing device or devices installed in said first tubing string below said lower bi-flow connector 
     
     
         7 . The artificial lift system of  claim 6 , further including a one-way check sub installed in said first tubing string below said casing annular sealing device(s) 
     
     
         8 . The artificial lift system of  claim 1 , further including an upper shroud surrounding said upper bi-flow connector and a lower shroud surrounding said lower bi-flow connector 
     
     
         9 . A method of modifying the artificial lift system of  claim 1 , the method comprising:
 removing the first fluid displacement device from the releaseably connected first sealing nipple;   inserting a third tubular string into the first tubular string with a second sealing nipple disposed in the third tubular string;   connecting the third tubular string to the upper bi-flow connector; and   inserting a second fluid displacement device into the second sealing nipple   
     
     
         10 . An artificial lift system for use in a wellbore extending from a surface to a subterranean reservoir containing reservoir fluids, the system comprising:
 a casing disposed in the wellbore;   a first tubular string disposed in the casing;   an upper bi-flow connector disposed in the first tubular string,   a lower bi-flow connector disposed in the first tubular string below the upper bi-flow connector;   a second tubular string disposed below the lower bi-flow connector and sealingly engaging the lower bi-flow connector, wherein the lower bi-flow connector allows flow between the second tubular string and the annulus between the casing and the first tubular string;   a third tubular string disposed in the first tubular string above the upper bi-flow connector;   a first fluid displacement device disposed in the third tubular above the upper bi-flow connector, wherein the upper bi-flow connector allows flow between an annulus formed by the casing and the first tubular string and the fluid displacement device; and   a second seating nipple disposed in the third tubular string above the upper bi-flow connector, wherein the fluid displacement device is releaseably connected to the second seating nipple   
     
     
         11 . The artificial lift system of  claim 10 , wherein said upper bi-flow connector comprises a tubular that contains a center bore in communication with one or more horizontal channel(s) that extend through the width of the device, and one or more vertical channel(s) that extend through the length of the device, and said horizontal channel(s) and said vertical channel(s) do not communicate with-in said bi-flow tool 
     
     
         12 . The artificial lift system of  claim 10 , wherein said center bore extends to the upper end of said upper bi-flow connector but does not extend to the lower end of said upper bi-flow connector 
     
     
         13 . The artificial lift system of  claim 10 , wherein said center bore extends to the upper and lower end of said upper bi-flow connector 
     
     
         14 . The artificial lift system of  claim 10 , wherein said lower bi-flow connector comprises a tubular that contains a center bore in communication with one or more horizontal channel(s) that extend through the width of the device, and one or more vertical channel(s) that extend through the length of the device, and said horizontal channel(s) and said vertical channel(s) do not communicate with-in said bi-flow tool and said center bore extends to the lower end of said tubular but does not extend to the upper end of said tubular 
     
     
         15 . The artificial lift system of  claim 10 , further including one or more casing annular sealing device or devices installed in said first tubing string below said lower bi-flow connector 
     
     
         16 . The artificial lift system of  claim 15 , further including a one-way check sub installed in said first tubing below said casing annular sealing device(s) 
     
     
         17 . The artificial lift system of  claim 10 , further including a third fluid displacement device installed in the second tubular string 
     
     
         18 . The artificial lift system of  claim 17 , further including one or more removeable plugs located in or between said upper and lower bi-flow connectors to allow said third fluid displacement device to be retrieved without having to remove wellbore tubulars 
     
     
         19 . The artificial lift system of  claim 10 , further including an upper shroud surrounding said upper bi-flow connector and a lower shroud surrounding said lower bi-flow connector 
     
     
         20 . A method of producing reservoir fluids using the artificial lift system of  claim 10 , the method comprising:
 injecting a fluid from the surface into the annulus between the first and third tubing string and the first and second tubing string.