Injection device

Abstract

An injection device for use in injecting a fluid into a target location includes a housing defining an inlet for communicating with a source of injection fluid, an outlet for communicating with a target injection location, and a separate reference port for communicating with a reference pressure source. The device also includes first and second valve members mounted within the housing, wherein the second valve member defines a flow path therethrough to facilitate fluid communication between the inlet and outlet of the housing. A sealing arrangement is provided between the second valve member and the housing such that fluid pressure at the housing inlet and housing reference port apply a force on the second valve member to cause said second valve member to move relative to the first valve member and vary flow between the inlet and the outlet.

1 . An injection device for use in injecting a fluid into a target location, comprising:
 a housing defining an inlet for communicating with a source of injection fluid, an outlet for communicating with a target injection location, and a separate reference port for communicating with a reference pressure source;   a first valve member mounted within the housing;   a second valve member mounted within the housing and defining a flow path therethrough to facilitate fluid communication between the inlet and outlet of the housing;   a sealing arrangement provided between the second valve member and the housing such that fluid pressure at the housing inlet and housing reference port apply a force on the second valve member to cause said second valve member to move relative to the first valve member and vary flow between the inlet and the outlet.   
     
     
         2 . The injection device according to  claim 1 , wherein a portion of the sealing arrangement is in communication with the inlet of the housing such that inlet pressure can establish a force on the second valve member in a first direction, and a portion of the sealing arrangement is in communication with the reference pressure port of the housing such that reference pressure can establish a force on the second valve member in a second direction which is opposite to the first direction. 
     
     
         3 . The injection device according to  claim 1 , wherein the sealing arrangement is configured such that movement of the second valve member is achieved in accordance with a pressure differential between inlet and reference pressures. 
     
     
         4 . The injection device according to  claim 1  wherein the sealing arrangement defines an inlet sealing area to be exposed to inlet pressure, and a reference sealing area to be exposed to reference pressure. 
     
     
         5 . The injection device according to  claim 4 , wherein the inlet and reference sealing areas are substantially equal. 
     
     
         6 . The injection device according to  claim 4 , wherein the inlet and reference sealing areas are different to establish a force bias on the second valve member by action of the inlet and reference pressures. 
     
     
         7 . The injection device according to  claim 1 , wherein inlet pressure establishes a force on the valve member to cause said valve member to move in a direction to increase flow and the reference pressure establishes a force on the valve member to cause said valve member to move in a direction to decrease flow. 
     
     
         8 . The injection device according to  claim 1 , wherein a portion of the sealing arrangement is in communication with the outlet of the housing. 
     
     
         9 . The injection device according to  claim 8 , wherein the sealing arrangement substantially eliminates the effect of outlet pressure on the valve member. 
     
     
         10 . The injection device according to  claim 8 , wherein the sealing arrangement is configured such that outlet pressure establishes first and second substantially equal and opposite forces on the second valve member, such that any net force is substantially minimised. 
     
     
         11 . The injection device according to  claim 8 , wherein the sealing arrangement is configured to permit the outlet pressure to provide a desired bias force on the second valve member. 
     
     
         12 . The injection device according to  claim 1 , wherein the sealing arrangement defines first and second outlet sealing areas between the second valve member and the housing, and each of the first and second outlet sealing areas is configured to be exposed to outlet pressure. 
     
     
         13 . The injection device according to  claim 12 , wherein the first and second sealing areas permit outlet pressure to generate a force on the second valve member in opposite directions. 
     
     
         14 . The injection device according to  claim 12 , wherein the first and second outlet sealing areas are substantially equal. 
     
     
         15 . The injection device according to  claim 12 , wherein the first and second outlet sealing areas are different. 
     
     
         16 . The injection device according to  claim 1 , wherein the sealing arrangement comprises one or more seal members. 
     
     
         17 . The injection apparatus according to  claim 1 , wherein the sealing arrangement includes first and second seal assemblies which extend between the second valve member and the housing. 
     
     
         18 . The injection apparatus according to  claim 17 , wherein each of the first and second seal assemblies comprise one or more seal members. 
     
     
         19 . The injection apparatus according to  claim 17 , wherein the first seal assembly isolates the housing inlet from the housing outlet, such that fluid communication between the inlet and the outlet is directed through the flow path in the second valve member. 
     
     
         20 . The injection apparatus according to  claim 17 , wherein the second seal assembly isolates the housing outlet from the housing reference port. 
     
     
         21 . The injection device according to  claim 17 , wherein the first seal assembly defines an inlet sealing area arranged in the device to be exposed to inlet pressure. 
     
     
         22 . The injection device according to  claim 17 , wherein the first seal assembly defines a first outlet sealing area arranged in the device to be exposed to outlet pressure. 
     
     
         23 . The injection device according to  claim 17 , wherein the second seal assembly defines a reference sealing area arranged in the device to be exposed to reference pressure. 
     
     
         24 . The injection device according to  claim 17 , wherein the second seal assembly defines a second outlet sealing area arranged in the device to be exposed to outlet pressure. 
     
     
         25 . The injection device according to  claim 1 , comprising a biasing arrangement operable to bias the second valve member in a desired direction. 
     
     
         26 . The injection device according to  claim 25 , wherein the biasing arrangement is operable to bias the second valve member to move in a direction to decrease flow between the inlet and the outlet. 
     
     
         27 . The injection device according to  claim 25 , wherein the second valve is arranged in the device to be actuated to move in a direction to decrease flow by a combination of biasing force from the biasing arrangement and the action of reference pressure, and to be actuated to move in a direction to increase flow by the action of inlet pressure. 
     
     
         28 . The injection device according to  claim 25 , wherein, in use, the biasing arrangement establishes a force on the second valve member to permit a desired pressure differential within the injection device to be achieved. 
     
     
         29 . The injection device according to  claim 1 , for use in injecting a fluid into a wellbore target location. 
     
     
         30 . The injection device according to  claim 1 , wherein, in use, the inlet fluid pressure at the inlet of the housing is at least partially defined by fluid pressure within at least one of an associated injection line and/or an associated source of injection fluid, and the outlet fluid pressure is at least partially defined by fluid pressure at an associated target location. 
     
     
         31 . The injection device according to  claim 1 , wherein the reference pressure is atmospheric or less than atmospheric. 
     
     
         32 . The injection device according to  claim 1 , wherein, in use, the reference pressure port is in communication with a source of reference pressure, excluding reference pressure from the target location. 
     
     
         33 . The injection device according to  claim 1 , wherein, in use, the reference pressure port is in communication with a local source of reference pressure. 
     
     
         34 . The injection device according to  claim 1 , comprising a source of reference pressure. 
     
     
         35 . The injection device according to  claim 34 , wherein the source of reference pressure is located within the housing. 
     
     
         36 . The injection device according to  claim 1 , wherein, in use, the reference pressure port is in communication with a source of reference pressure at a remote location. 
     
     
         37 . The injection device according to  claim 1 , where, in use, the outlet of the housing is in communication with a target location which is positioned on one side of a pressure varying device, and the reference pressure port is in communication with a location which is positioned on an opposite side of the pressure varying device. 
     
     
         38 . The injection device according to  claim 37 , wherein the pressure varying device may comprise a pump. 
     
     
         39 . The injection device according to  claim 1 , wherein, in use, the outlet of the housing is in communication with an inlet of a pump assembly, and the reference pressure port is in communication with an outlet of the same pump assembly. 
     
     
         40 . The injection device according to  claim 1 , wherein reference pressure applied at the reference pressure port is user variable. 
     
     
         41 . The injection device according to  claim 1 , wherein the first and second valve members cooperate to define a restriction to flow to establish a back pressure in the inlet side assisting to maintain the inlet pressure above the outlet pressure. 
     
     
         42 . The injection device according to  claim 1 , wherein the first and second valve members are selectively engeagable to permit the first valve member to selectively seal the flow path in the second valve member. 
     
     
         43 . The injection device according to  claim 42 , wherein the second valve member is moveable within the housing to become separated form the first valve member, to thus permit flow through the flow path. 
     
     
         44 . The injection device according to  claim 1 , wherein the first valve member is fixed relative to the housing, such that movement of the second valve member is required to vary flow. 
     
     
         45 . The injection device according to  claim 1 , wherein the first valve member is defined by a component which is separate from the housing, and said first valve member is permitted to move within the housing. 
     
     
         46 . The injection device according to  claim 1 , wherein the first valve member is located on the inlet side of the second valve member. 
     
     
         47 . The injection device according to  claim 1 , comprising a limiting arrangement for limiting or restricting movement of the first valve member, wherein the limiting arrangement functions to limit movement of the first valve member at a point of limitation and permit the second valve member to move beyond the point of limitation and to become disengaged from the first valve member. 
     
     
         48 . The injection device according to  claim 1 , comprising at least one check valve for preventing flow through the injection device in a direction from the outlet to the inlet. 
     
     
         49 . A method for injecting a fluid into a target location, comprising:
 communicating an injection fluid to an inlet of a housing of an injection device;   communicating an outlet of the housing to a target location;   communicating a reference port of the housing to a source of reference pressure;   causing a second valve member to move relative to a first valve member by exposure to pressure at the inlet of the housing and pressure at the reference pressure port of the housing, wherein such movement permits flow through a flow path of the valve member to be adjusted.   
     
     
         50 . A pumping system comprising:
 a flow line;   a pump associated with the flow line and defining an inlet side and an outlet side;   an injection device according to  claims 1 , wherein the outlet of the injection device housing is in communication with the flow line on an inlet side of the pump.   
     
     
         51 . The pumping system according to  claim 50 , wherein the reference pressure port of the injection device housing is in communication with the flow line on an outlet side of the pump. 
     
     
         52 . An injection system for injecting a fluid into a target location, comprising:
 an injection line in communication with a source of injection fluid;   an injection device coupled to the injection line and comprising:
 a housing defining an inlet coupled to the injection line, an outlet for communicating with a target injection location, and a separate reference port for communicating with a reference pressure source; 
 a first valve member mounted within the housing; 
 a second valve member mounted within the housing and defining a flow path therethrough to facilitate fluid communication between the inlet and outlet of the housing; and 
 a sealing arrangement provided between the second valve member and the housing and configured such that fluid pressure at the housing inlet and housing reference port apply a force on the second valve member to cause said second valve member to move relative to the first valve member and vary flow between the inlet and the outlet. 
   
     
     
         53 . The injection system according to  claim 52 , wherein the injection device defines a first injection device and the injection system comprises a second injection device located upstream of the first injection device. 
     
     
         54 . The injection device according to  claim 53 , wherein the second injection device comprises an outlet in communication with the inlet of the first injection device. 
     
     
         55 . A method for creating an injection system, comprising:
 determining a required pressure differential between an injection line and a target injection location which maintains the injection line at a positive pressure;   determining an operational threshold pressure differential of an injection fluid;   determining a required number of discrete pressure reduction stages within the injection line to provide the required pressure differential between the injection line and target location while maintaining each pressure reduction stage below the operational threshold pressure differential of the injection fluid; and   installing a number of injection devices within an injection line to correspond to the determined number of discrete pressure reduction stages.