Chemically targeted control of downhole flow control devices

Abstract

Systems and methods using enhanced flow control devices are described. The flow control devices can be selectively closed completely or have its effective flow area reduced to restrict production (or injection) by use of a chemical trigger mechanism. In addition, some of the systems described herein deploy specific targeted chemical tracers, dissolvable in the unwanted production fluid (e.g. water or gas). These chemical tracers once dissolved will enter the production stream and be identified at the surface. The identification will determine which segment of the completion is producing the unwanted fluid. According to some embodiments, an appropriate chemical trigger is placed, for example, by pumping down through the tubing and utilizing intelligent completion valve to place the chemical, or by spotting with coiled tubing and bullhead to the formation, or by other methods of chemical placement. The chemical trigger will only trigger the active chemical in the appropriate flow control device. This chemical will then change state—dissolve, create thermal reaction, create a pressure swell or expand—which in turn allows a mechanical device to shift position such that a valve in the flow control device closes, or reduces its flow by restricting the flow area by swelling/expansion of the active chemical.

What is claimed is: 
     
         1 . A method of chemically targeting control of flow control devices installed in a wellbore comprising:
 by an operator, selecting for actuation at least one of a plurality of flow control devices previously installed in a wellbore, leaving at least one of said plurality of flow control devices as non-selected for actuation;   selecting a triggering chemical fluid configured to selectively trigger actuation of said flow control devices selected for actuation and configured not to trigger actuation of said flow control devices non-selected for actuation;   flowing said selected triggering chemical fluid from a surface location through the wellbore and to expose both said flow control devices selected for actuation and said flow control devices non-selected for actuation to said triggering chemical fluid;   selectively triggering actuations of said flow control devices selected for actuation, said actuations being caused by one or more chemical reactions resulting from exposure with said triggering chemical fluid, leaving un-actuated said flow control devices non-selected despite being exposed to said triggering chemical fluid.   
     
     
         2 . A method according to  claim 1  wherein the introduced chemical causes an exothermic chemical reaction used to actuate a choking member. 
     
     
         3 . A method according to  claim 1  wherein at least one of the plurality of flow control devices includes a pneumatic valve, and the introduced chemical causes a reaction to generate gas to actuate the pneumatic valve. 
     
     
         4 . A method according to  claim 3  wherein the gas generating reaction includes an acid reacting with one or more substances selected from a group consisting of sodium carbonate, sodium bicarbonate, calcium carbonate and sodium nitride (NaNO 2 ). 
     
     
         5 . A method according to  claim 1  wherein the introduced chemical reacts with a material in the flow control device so as to release a plurality of sealing members that seal one or more orifices in flow control device. 
     
     
         6 . A method according to  claim 5  wherein the sealing members are spherical in shape. 
     
     
         7 . A method according to  claim 5  wherein the sealing members are of irregular shape. 
     
     
         8 . A method according to  claim 1  wherein the introduced chemical causes swelling of portions within the flow control device so as to restrict fluid flow within the flow control device. 
     
     
         9 . A method according to  claim 1  wherein the introduced chemical is located downhole and is automatically released in the presence of an unwanted fluid, thereby automatically actuating the subset of the plurality of flow control devices without further human intervention or control. 
     
     
         10 . A method according to  claim 9  wherein the induced chemical is encapsulated in a material that reacts or dissolves in the presence of the unwanted fluid, and the encapsulating material can be detected on the surface to indicate the location of production of the unwanted fluid. 
     
     
         11 . A wellbore penetrating a subterranean formation having a plurality of flow control devices installed therein comprising:
 a first flow control device installed in the wellbore being actuable upon exposure to a first triggering chemical, but not upon exposure to a second triggering chemical; and   a second flow control device installed in the wellbore being actuable upon exposure to the second triggering chemical, but not actuable upon exposure to the first triggering chemical.   
     
     
         12 . A wellbore according to  claim 11  further comprising a third flow control device installed in a wellbore being actuable upon exposure to a third triggering chemical, but not actuable upon exposure to the first and second triggering chemicals. 
     
     
         13 . A wellbore according to  claim 11  wherein each flow control device controls fluid flowing into the wellbore from a zone of the subterranean formation, the flow control devices being arranged in a series within a portion of the wellbore, and an introduced triggering chemical flows to each of the flow control devices so as to expose at least a portion of each flow control device to the introduced chemical. 
     
     
         14 . A wellbore according to  claim 11  wherein the first flow control device includes a mechanical stop retaining a choking member actuated with one or more spring members, and the mechanical stop is dissolvable by the first triggering chemical but not by the second triggering chemical. 
     
     
         15 . A wellbore according to  claim 11  wherein the first triggering chemical causes an exothermic chemical reaction within the first flow control device. 
     
     
         16 . A wellbore according to  claim 11  wherein the first triggering chemical causes the release of a plurality of sealing members that seal one or more orifices in the first flow control device. 
     
     
         17 . A wellbore according to  claim 11  wherein the first triggering chemical causes swelling of portions within the first flow control device so as to restrict fluid flow within the first flow control device. 
     
     
         18 . A wellbore according to  claim 11  further comprising a flowline to the first and second flow control devices, the flowline being separate from a production fluid flowline through which fluid produced from the subterranean formation flows into the wellbore. 
     
     
         19 . A wellbore according to  claim 11  wherein the first flow control device is associated with a first chemical tracer material and the second flow control device is associated with a second chemical tracer material, the first and second tracer materials being releasable in the presence of an undesirable fluid. 
     
     
         20 . A wellbore according to  claim 11  wherein the wellbore includes a motherbore and a plurality of lateral wellbores branching from the motherbore, and wherein the first and second flow control devices are positioned within one of the lateral wellbores. 
     
     
         21 . A wellbore according to  claim 11  wherein the first triggering chemical is located upstream from the first flow control device and is automatically released in the presence of an unwanted fluid, thereby automatically actuating the first flow control device without human intervention or control. 
     
     
         22 . A wellbore according to  claim 21  wherein the first triggering chemical is encapsulated in a material that reacts or dissolves in the presence of the unwanted fluid and the encapsulating material can be detected on the surface to indicate the location of the production of the unwanted fluid. 
     
     
         23 . A wellbore according to  claim 11  wherein the first flow control device includes an indicator chemical that is released into the wellbore when the device is actuated, the indicator chemical being detectable on the surface thereby indicating confirmation of actuation of the device.