Method for displacement of water from a porous and permeable formation

Abstract

A method and system for displacing water from a porous geological formation are provided. The zone to be displaced is defined by the injection of water into one or more barrier wells around the zone. One or more gas injection wells and water production wells are located within the zone. During pressurized gas injection within the zone, the barrier wells are operated to achieve a hydraulic pressure barrier surrounding the zone that is sufficient to prevent penetration therethrough by the injected gas. The well system is operated to concurrently limit gas entry into the water production well. Accordingly, the gas displaces water downward within the zone such that water is produced at the water production wells.

1 . A method for displacing water from a target region of a permeable geological formation with a volume of injected gas, the method comprising the steps of:
 identifying a target region of the formation from which water is to be displaced;   providing a series of barrier wells along permeable boundaries of the target region;   providing a gas injection well within the target region;   injecting fluid into the barrier wells to establish a gas-confining barrier around the target region;   providing a production well within the gas-confining barrier; and   operating the gas injection well and the production well concurrently to effect a net production of water from the target region while maintaining the gas-confining barrier around the target region.   
     
     
         2 . The method as in  claim 1 , further comprising the step of monitoring fluid composition of the geological formation outside the target region. 
     
     
         3 . The method as in  claim 1 , further comprising the step of controlling fluid injection into the barrier wells and from the production well to maintain the hydraulic pressure at the gas-confining barrier in excess of the hydraulic pressure within the target region, thereby limiting escape of gas from the target region. 
     
     
         4 . The method as in  claim 1 , further comprising the step of monitoring gas production from the production well. 
     
     
         5 . The method as in  claim 1 , further comprising the step of controlling the rate of water production from the production well to reduce gas production from the production well. 
     
     
         6 . The method as in  claim 1 , further comprising the step of recovering a resource from a formation beneath the target region. 
     
     
         7 . The method as in  claim 1 , wherein the gas is air, carbon dioxide, nitrogen, methane, exhaust gas, enriched air, or oxygen. 
     
     
         8 . The method as in  claim 1 , further comprising the step of directing produced water from the production well to the barrier well(s). 
     
     
         9 . The method as in  claim 1 , further comprising the step of producing hydrocarbons from a hydrocarbon-bearing formation proximal to the target region. 
     
     
         10 . The method as in  claim 1 , further comprising the step of producing hydrocarbons from a formation beneath the target region. 
     
     
         11 . The method as in  claim 10 , wherein the step of producing hydrocarbons comprises steam injection into the formation beneath the target region. 
     
     
         12 . The method as in  claim 1  further comprising repeating each step in the method in respect of a further target region of the permeable formation to displace water from said further target region, while continuing to operate said barrier wells, gas injection well, and production well. 
     
     
         13 . The method as in  claim 1 , wherein said gas-confining barrier is maintained by continuous fluid injection into the barrier wells. 
     
     
         14 . The method as in  claim 1 , wherein said gas-confining barrier is maintained by periodic fluid injection into the barrier wells. 
     
     
         15 . A well system for use in removal of water from a target region of a permeable geological formation, the well system comprising:
 a series of fluid injection wells defining a boundary along a target region within the permeable geologic formation, the injection wells operable to establish a hydraulic pressure barrier along said laterally permeable boundary;   one or more gas injection wells operable to deliver pressurized gas into the target region; and   one or more production wells located within the target region, the production wells operable independently from operation of the injection wells to produce native water from the target region.   
     
     
         16 . The well system as in  claim 15 , wherein the series of fluid injection wells comprises one or more horizontal, deviated, or branched wellbores. 
     
     
         17 . The well system as in  claim 15 , wherein the gas injection well comprises a horizontal, deviated, or branched wellbores. 
     
     
         18 . The well system as in  claim 17 , wherein the gas injection well extends outside the target region to supply injected gas to a further target region within the formation. 
     
     
         19 . The well system as in  claim 15 , further comprising a source of pressurized gas. 
     
     
         20 . The well system as in  claim 19 , wherein the pressurized gas is air, carbon dioxide, nitrogen, methane, exhaust gas, enriched air, or oxygen. 
     
     
         21 . A system for displacement of water from a permeable geological formation, the system comprising:
 one or more gas-confining hydraulic pressure barriers established within the permeable geological formation to hydraulically isolate a target region, the gas-confining hydraulic pressure barriers provided by fluid injection into a series of barrier wells surrounding the target region;   a gas injection well extending into the target region and operable to displace water within the target region;   one or more water production wells within the target region, the water production wells operable independently from operation of the injection wells to effect a net production of water from the target region.   
     
     
         22 . The system as in  claim 21 , wherein the series of fluid injection wells comprises one or more horizontal, deviated, or branched wellbores. 
     
     
         23 . The system as in  claim 21 , wherein the gas injection well comprises a horizontal, deviated, or branched wellbores. 
     
     
         24 . The system as in  claim 21 , wherein the gas injection well extends outside the target region to supply injected gas to a further target region within the formation. 
     
     
         25 . The system as in  claim 21 , further comprising a source of pressurized gas. 
     
     
         26 . The system as in  claim 25 , wherein the pressurized gas is air, carbon dioxide, nitrogen, methane, exhaust gas, enriched air, or oxygen. 
     
     
         27 . A method for displacing fluid from a target region within a permeable geological formation, the method comprising the steps of:
 identifying a target region of the formation from which water is to be displaced;   providing a series of barrier wells along permeable boundaries of the target region;   injecting fluid into the barrier wells to establish a hydraulic pressure boundary at or within the target region; and   concurrently producing fluid from a production well within the target region at a rate sufficient to effect a net production of fluid from the target region.   
     
     
         28 . The method as in  claim 27 , further comprising the step of providing communication means between the permeable geological formation and a source of gas at surface. 
     
     
         29 . The method as in  claim 27 , wherein the source of gas is air. 
     
     
         30 . The method as in  claim 27 , further comprising the step of controlling fluid injection into the barrier wells and from the production well to maintain the hydraulic pressure barrier in excess of the hydraulic pressure within the target region, thereby limiting escape of gas from the target region. 
     
     
         31 . The method as in  claim 27 , further comprising the step of monitoring gas production from the production well. 
     
     
         32 . The method as in  claim 27 , further comprising the step of controlling the rate of water production from the production well to reduce gas production from the production well. 
     
     
         33 . The method as in  claim 27 , further comprising the step of recovering a resource from a formation beneath the target region. 
     
     
         34 . The method as in  claim 27 , further comprising the step of directing produced water from the production well to the barrier well. 
     
     
         35 . The method as in  claim 27 , further comprising the step of producing hydrocarbons from a hydrocarbon-bearing formation proximal to the target region. 
     
     
         36 . The method as in  claim 27 , further comprising the step of producing hydrocarbons from a formation beneath the target region. 
     
     
         37 . The method as in  claim 36 , wherein the step of producing hydrocarbons comprises steam injection into the formation beneath the target region. 
     
     
         38 . The method as in  claim 27 , further comprising repeating each step in the method in respect of a further target region of the permeable formation to displace water from said further target region, while continuing to operate said barrier wells, gas injection well, and production well.