Hydraulically Driven Downhole Pump Using Multi-Channel Coiled Tubing

Abstract

This invention relates to a coiled tubing installed and operated hydraulically driven downhole pump for hydrocarbon wells and especially hydrocarbon gas wells that are prone to produce fluids that choke gas production. The hydraulically driven downhole pump is driven by a closed loop surface positioned hydraulic power system. Should the hydraulically driven downhole pump become inoperative, it may be quickly retrieved and immediately replaced using a coiled tubing unit as compared to a workover rig. A coiled tubing unit is able to pull the coiled tubing string and re-install the string quite rapidly because the coiled tubing does not have joints that need to be disassembled or reconnected. The manpower needs and costs for replacement are considerably less and lost production of the well is substantially reduced.

1 . An apparatus for producing fluids in a wellbore wherein gas is produced through one annular space and fluids are produced through a separate space; wherein the apparatus comprises:
 a. casing in the wellbore;   b. production tubing within the casing;   c. a hydraulically driven downhole pump within the production tubing and attached to the distal end of a multi-channel coiled tubing string that extends to the surface of the borehole;   d. a hydraulic power unit disposed at the surface and connected to the multi-channel coiled tubing string so as to provide high pressure hydraulic fluid into a first channel within the multi-channel coiled tubing string and receive hydraulic fluid through a second channel within the multi-channel coiled tubing string and together define a closed loop hydraulic fluid system where hydraulic fluid is not mixed with production fluids; and   e. whereby a fluid production space is defined within the production tubing and outside the multi-channel coiltubing driven by the hydraulically driven downhole pump and further whereby a gas production space is defined outside of the production tubing and within the casing.   
     
     
         2 . The apparatus according to  claim 1 , wherein the hydraulic power unit includes a power take off device and for a gas compressor for compressing the produced gas from the well site using a single power unit. 
     
     
         3 . The apparatus according to  claim 1 , wherein the hydraulic power unit provides a continuous supply of high pressure hydraulic fluid through said first channel of said coiled tubing string and continuously receives lower pressure hydraulic fluid from said second channel of said coiled tubing string into a reservoir. 
     
     
         4 . The apparatus according to  claim 1 , wherein the multi-channel coiled tubing string comprises two coiled tubing strings, one concentrically located within another defining the first channel to be axially within the inner coiled tubing string and the second channel being the annular space outside of the inner coiled tubing string and within the outer coiled tubing string. 
     
     
         5 . The apparatus according to  claim 1 , wherein the multi-channel coiled tubing string comprises an outer wall and a continuous web section within the outer wall dividing the interior of the coiled tubing string into two separate and distinct side-by-side channels. 
     
     
         6 . The apparatus according to  claim 1 , further including a standing valve and seal assembly by which accepts the hydraulically driven downhole pump and which provides well control during the insertion and pulling and replacing of the hydraulically driven downhole pump. 
     
     
         7 . The apparatus according to  claim 1 , further including a heat transfer device for heating the hydraulic fluid and thereby heat the wellbore to prevent ice from forming and maintain any paraffinic hydrocarbons above their cloud point. 
     
     
         8 . The apparatus according to  claim 7 , wherein the heat transfer device is a liquid/liquid heat exchanger where coolant from an internal combustion engine that is used to drive the hydraulic power unit is arranged to provide some of the heat in the coolant to the hydraulic fluid. 
     
     
         9 . A process for co-producing hydrocarbon gas and produced fluids separately from a wellbore wherein the process comprises:
 a. providing casing in the wellbore;   b. inserting production tubing within the casing;   c. attaching a hydraulically driven downhole pump to the distal end of a multi-channel coiled tubing string;   d. inserting the hydraulically driven downhole pump and multi-channel coiled tubing string into the production tubing within the wellbore;   e. providing high pressure hydraulic fluid from a hydraulic power unit to the distal end of the multi-channel coiled tubing string so that high pressure hydraulic fluid is delivered by the hydraulic power unit and to the downhole hydraulically driven pump and returns to the hydraulic power unit through a second channel in the multi-channel coiled tubing string thereby pumping produced fluid in the wellbore up through the annular space within the production tubing but outside the multi-channel coiled tubing string while hydrocarbon gas is produced in the annular space within the casing but outside the production string.   
     
     
         10 . The process according to  claim 9 , further including the step of providing power to the hydraulic power unit and providing compression of the produced gas from a common power source for the well site. 
     
     
         11 . The process according to  claim 9 , wherein the step of providing high pressure hydraulic fluid from the power unit further comprises providing a continuous supply of high pressure hydraulic fluid through said first channel of said coiled tubing string and continuously receives lower pressure hydraulic fluid from said second channel of said coiled tubing string into a reservoir. 
     
     
         12 . The process according to  claim 9 , wherein the step of providing a multi-channel coiled tubing string comprises providing a multi-channel coiled tubing string having an outer wall and a continuous web section within the outer wall dividing the interior of the coiled tubing string into two separate and distinct, side-by-side channels. 
     
     
         13 . The process according to  claim 9 , wherein the step of providing a multi-channel coiled tubing string further comprises providing two coiled tubing strings, one concentrically located within another so that the first channel is axially within the inner coiled tubing string and the second channel in the annular space outside of the inner coiled tubing string and inside of the outer coiled tubing string. 
     
     
         14 . The process according to  claim 13 , wherein the process further includes the steps of installing the outer coiled tubing string into the production tubing and then installing the inner coiled tubing string into the outer coiled tubing string, connecting the two coiled tubing strings together with a pump adaptor attached to the outer coiled tubing string and a stinger attached to the inner coiled tubing string and suited for stinging into the pump adaptor. 
     
     
         15 . The process according to  claim 9 , further including the step of heating the hydraulic power fluid to thereby heat the wellbore and prevent the formation of ice and maintain any paraffinic hydrocarbons to be above their cloud point. 
     
     
         16 . The process according to  claim 15 , where the step of heating the hydraulic power fluid to comprises heating the hydraulic fluid using heat from an internal combustion engine by providing coolant from the internal combustion engine into heat exchange contact with the hydraulic fluid. 
     
     
         17 . An apparatus for producing fluids in a wellbore wherein gas is produced through one annular space and fluids are produced through a separate space; wherein the apparatus comprises:
 a. casing in the wellbore;   b. a hydraulically driven downhole pump within the casing and attached to the distal end of a multi-channel coiled tubing string that extends to the surface of the borehole;   c. a hydraulic power unit disposed at the surface and connected to the multi-channel coiled tubing string so as to provide high pressure hydraulic fluid into a first channel within the multi-channel coiled tubing string and receive hydraulic fluid through a second channel within the multi-channel coiled tubing string and together define a closed loop hydraulic fluid system where hydraulic fluid is not mixed with production fluids; and   d. a third channel for the production of fluid from the hydraulically driven downhole pump separate from the production path of gas production.