Method and pump apparatus for removing liquids from wells

Abstract

A method and pump apparatus for removing formation fluids from a “liquid loaded” gas well is provided. The pump apparatus is adapted to be positioned downhole a well and is hydraulically operated to lift formation fluid, such as water from the well to “unload” the well and reestablish gas production. The pump apparatus includes a pump body, a hydraulic head connected to the pump body, and a displacement plunger operated by the hydraulic head to reciprocate the displacement plunger within pump body to draw-in and displace formation fluid from the pump apparatus. The pump apparatus is a fluid displacement type pump and has a low power consumption affording use of the pump apparatus at even the most remote well locations. Additionally, a method of operating the pump apparatus is provided.

1 . A hydraulic fluid displacement pump comprising: 
 a pump body having an exterior surface and defining an axial bore comprising a first chamber and a second chamber which are separated by a diametrically reduced section of said axial bore, said pump body further defining at least one gas vent extending from said exterior surface into said first chamber, a fluid inlet port extending from said exterior into said second chamber, and a fluid discharge port extending from said exterior thereof into said second chamber;    a hydraulic head attached to said pump body;    a displacement plunger, said displacement plunger extending from said hydraulic head through said axial bore and which is operated by said hydraulic head to be reciprocated within said axial bore, said displacement plunger defining a vent passage through a distal end thereof;    a hydraulic circuit attached to said hydraulic head;    a fluid discharge conduit connected to said fluid discharge port;    a first check valve inline with said fluid discharge conduit;    a second check valve connected to said fluid inlet port; and    a lift tube, wherein said lift tube is in fluid communication with said discharge conduit.    
   
   
       2 . The hydraulic fluid displacement pump of  claim 1 , wherein said first chamber and said second chamber are of diameters which are greater then the diameter of said displacement plunger.  
   
   
       3 . The hydraulic fluid displacement pump of  claim 1 , further comprising: 
 a casing having an interior volume, said casing enclosing said pump body and said hydraulic head within said interior volume, said casing defining a first fluid passage in fluid communication with said interior volume at a first end thereof and a second fluid passage in fluid communication with said interior volume at a second end thereof; and    wherein said lift tube is attached to said casing and is sealed from said interior volume thereof.    
   
   
       4 . The hydraulic fluid displacement pump of  claim 1 , further comprising a control system operatively connected to said hydraulic circuit to control the reciprocation of said displacement plunger.  
   
   
       5 . The hydraulic fluid displacement pump of  claim 4 , wherein said control system is comprises a programmable logic controller.  
   
   
       6 . The hydraulic fluid displacement pump of  claim 1 , wherein said first chamber and said second chamber are fluidically sealed from one another by said displacement plunger extending through said diametrically reduced section.  
   
   
       7 . A hydraulic fluid displacement pump comprising: 
 a pump body having an exterior surface, said pump body defining an axial bore, a fluid inlet port extending said exterior into said axial bore, a fluid discharge port extending from said exterior surface into said axial bore, and a vent port extending from said exterior surface into said axial bore;    a hydraulic head attached to said pump body and positioned within said casing;    a displacement plunger which extends from said hydraulic head through said axial bore and which is operated by said hydraulic head to be reciprocated within said axial bore;    a hydraulic circuit attached to said hydraulic head;    a fluid discharge conduit connected to said fluid discharge port;    a first check valve inline with said fluid discharge conduit;    a second check valve connected to said fluid inlet port;    a lift tube, wherein said lift tube is in fluid communication with said discharge conduit; and    a vent valve attached to said vent port.    
   
   
       8 . The hydraulic fluid displacement pump of  claim 7 , further comprising a control system operatively connected to said hydraulic circuit to control the reciprocation of said displacement plunger.  
   
   
       9 . The hydraulic fluid displacement pump of  claim 7 , wherein said vent valve is a normally closed valve and is operated to open based upon a predetermined fluid pressure within said hydraulic circuit.  
   
   
       10 . The hydraulic fluid displacement pump of  claim 7 , further comprising: 
 a casing having an interior volume and enclosing said pump body and said hydraulic head within said interior volume, said casing defining a first fluid passage in fluid communication with said interior volume at a first end thereof and a second fluid passage in fluid communication with said interior volume at a second end thereof; and    wherein said lift tube is attached to said casing and is sealed from said interior volume thereof.    
   
   
       11 . The hydraulic fluid displacement pump of  claim 7 , wherein said axial bore is of a diameter greater then the diameter of said displacement plunger.  
   
   
       12 . A method of operating a fluid displacement pump to remove fluid from a liquid loaded well comprising the steps of: 
 providing a hydraulically operated fluid displacement pump connected to a hydraulic circuit;    positioning said fluid displacement pump downhole;    operating said fluid displacement pump intermittently to vent said pump of gas, load said pump with formation fluid and to discharge said formation fluid to the surface of the well.    
   
   
       13 . The method of  claim 12 , wherein said displacement pump comprises: 
 a pump body having an exterior surface and defining an axial bore comprising a first chamber and a second chamber which are separated by a diametrically reduced section of said axial bore, said pump body further defining at least one gas vent extending from said exterior surface into said first chamber, a fluid inlet port extending from said exterior into said second chamber, and a fluid discharge port extending from said exterior thereof into said second chamber;    a hydraulic head attached to said pump body, said hydraulic head connected to said hydraulic circuit;    a displacement plunger which extends from said hydraulic head through said axial bore and which is operated by said hydraulic head to be reciprocated within said axial bore, said displacement plunger defining a vent passage through a distal end thereof;    a fluid discharge conduit connected to said fluid discharge port;    a first check valve inline with said fluid discharge conduit;    a second check valve connected to said fluid inlet port;    a lift tube, wherein said lift tube is in fluid communication with said discharge conduit; and    wherein said step of intermittent operation includes raising said displacement plunger within said axial bore to a raised position, holding said displacement plunger at said raised position for a predetermined time to vent gas from said pump body and to load said pump body with formation fluid, and then lowering said displacement plunger within said axial bore to displace said formation fluid from said pump body to the surface of the well.    
   
   
       14 . The method of  claim 12 , wherein said fluid displacement pump is operated intermittently by a programmable logic controller.  
   
   
       15 . The method of  claim 12 , wherein said displacement pump comprises: 
 a pump body having an exterior surface, said pump body defining an axial bore, a fluid inlet port extending said exterior into said axial bore, a fluid discharge port extending from said exterior surface into said axial bore, and a vent port extending from said exterior surface into said axial bore;    a hydraulic head attached to said pump body, said hydraulic head connected to said hydraulic circuit;    a displacement plunger which extends from said hydraulic head through said axial bore and which is operated by said hydraulic head to be reciprocated within said axial bore;    a hydraulic circuit attached to said hydraulic head;    a fluid discharge conduit connected to said fluid discharge port;    a first check valve inline with said fluid discharge conduit;    a second check valve connected to said fluid inlet port;    a lift tube, wherein said lift tube is in fluid communication with said discharge conduit;    a vent valve attached to said vent port; and    wherein said step of intermittent operation includes raising said displacement plunger to a raised position within said axial bore, opening said vent valve, holding said displacement plunger at said raised position to vent gas from said pump body and to load said pump body with formation fluid, closing said vent valve, and then lowering said displacement plunger within said axial bore to displace said formation fluid from said pump body to the surface of the well.