Pumps and methods of pumping fluids into a well bore

Abstract

A pump for pumping fluid down a well bore in a rock formation comprises: intake and discharge passages; a pumping chamber with a plunger therein; intake and discharge valve assemblies in the intake passage and the discharge passages. At least one valve assembly has a valve body movable into sealing contact with the valve seat by fluid pressure in the pumping chamber. The valve seat may have a cylindrical outer surface for mating reception in said intake passage, and a shoulder with a radially-projecting surface biased against a wall for sealing. A cushioning member may be interposed between the valve body and the valve seat. A seal may be interposed between said valve body and said valve seat, and configured so that between 35% and 60% of a sealing surface of said valve seat contacts the valve body.

What is claimed is: 
     
         1 . A pump for pumping fluid down a well bore in a rock formation, comprising:
 an intake passage in communication with a fluid reservoir;   a discharge passage in communication with said well bore in said rock formation;   a pumping chamber with a plunger received therein for pumping fluid from said reservoir to said well bore by reciprocation of said plunger;   intake and discharge valve assemblies in said intake passage and said discharge passage, respectively, for selectively sealing said intake and discharge passages, at least one of said intake and discharge valve assemblies comprising a valve body and a valve seat, said valve body movable into sealing contact with said valve seat by fluid pressure;   a cushioning member interposed between said valve body and said valve seat.   
     
     
         2 . The pump of  claim 1 , wherein said valve body contacts said cushioning member prior to contacting said valve seat, thereby decelerating said valve body. 
     
     
         3 . The pump of  claim 1 , wherein said cushioning member comprises an elastomeric ring. 
     
     
         4 . The pump of  claim 1 , wherein said cushioning member comprises a spring. 
     
     
         5 . The pump of  claim 1 , wherein said cushioning member is received in a channel in said valve seat. 
     
     
         6 . The pump of  claim 1 , wherein said cushioning member is received in a channel in said valve body. 
     
     
         7 . The pump of  claim 4 , wherein, during sealing contact of said valve body and said valve seat, said cushioning member is compressed such that it does not protrude from said channel. 
     
     
         8 . The pump of  claim 5 , further comprising a second cushioning member received in a channel in said valve body. 
     
     
         9 . The pump of  claim 1 , wherein said valve seat has a cylindrical outer surface for mating reception in said intake passage, and a shoulder with a radially-projecting surface biased against a wall of said intake passage by pressure in said pumping chamber, for sealing therewith. 
     
     
         10 . The pump of  claim 9 , further comprising a compressible seal positioned about the perimeter of said valve body and interposed between said valve body and said valve seat, said compressible seal configured so that, with said valve body in sealing contact with said valve seat, between 35% and 60% of a sealing surface of said valve seat is in contact with said valve body. 
     
     
         11 . A pump for pumping fluid down a well bore in a rock formation, comprising:
 an intake passage in communication with a fluid reservoir;   a discharge passage in communication with said well bore in said rock formation;   a pumping chamber with a plunger received therein for pumping fluid from said reservoir to said well bore by reciprocation of said plunger;   intake and discharge valve assemblies in said intake passage and said discharge passage, respectively, for selectively sealing said intake and discharge passages, at least one of said intake and discharge valve assemblies comprising a valve body and a valve seat;   said valve body movable by fluid pressure into sealing contact with said valve seat;   said valve seat having a cylindrical outer surface for mating reception in said intake passage or said discharge passage, and a shoulder with a radially-projecting surface biased against a wall of said passage by pressure in said pumping chamber, for sealing therewith.   
     
     
         12 . The pump of  claim 11 , further comprising a resilient seal member interposed between said radially-projecting shoulder and said wall of said intake or discharge passage. 
     
     
         13 . The pump of  claim 12 , further comprising a resilient seal member interposed between said cylindrical outer surface of said valve seat and a wall of said intake or discharge passage. 
     
     
         14 . The pump of  claim 12 , wherein said resilient seal member is received in a channel in said shoulder. 
     
     
         15 . The pump of  claim 11 , further comprising a compressible seal positioned about the perimeter of said valve body and interposed between said valve body and said valve seat, said compressible seal configured so that, with said valve body in sealing contact with said valve seat, between 35% and 60% of a sealing surface of said valve seat is in contact with said valve body. 
     
     
         16 . A pump for pumping fluid down a well bore in a rock formation, comprising:
 an intake passage in communication with a fluid reservoir;   a discharge passage in communication with said well bore in said rock formation;   a pumping chamber with a plunger received therein for pumping fluid from said reservoir to said well bore by reciprocation of said plunger;   intake and discharge valve assemblies in said intake passage and said discharge passage, respectively, for selectively sealing said intake and discharge passages, said intake valve assembly comprising a valve body and a valve seat;   said valve body movable by fluid pressure into sealing contact with said valve seat;   a compressible seal positioned about the perimeter of said valve body and interposed between said valve body and said valve seat, said compressible seal configured so that, with said valve body in sealing contact with said valve seat, between 35% and 60% of a sealing surface of said valve seat is in contact with said valve body.   
     
     
         17 . The pump of  claim 16 , wherein said compressible seal is received in a channel defined in said valve body. 
     
     
         18 . The pump of  claim 17 , wherein said compressible seal has a notch for receiving a corresponding tab projecting from said valve body to lock said compressible seal in said channel. 
     
     
         19 . The pump of  claim 16 , further comprising a cushioning member interposed between said valve body and said valve seat. 
     
     
         20 . The pump of  claim 1 , wherein said pump is for hydraulic fracturing in said reservoir. 
     
     
         21 . The pump of  claim 11 , wherein said pump is for hydraulic fracturing in said reservoir. 
     
     
         22 . The pump of  claim 16 , wherein said pump is for hydraulic fracturing in said reservoir. 
     
     
         23 . A method of pumping fluid into a wellbore, comprising:
 drawing a fluid through an intake valve of the pump of  claim 1  by moving said plunger through an intake stroke;   moving said plunger through a discharge stroke, thereby pressurizing fluid in said chamber, closing said intake valve and opening said discharge valve and forcing said fluid through said discharge valve into said wellbore.   
     
     
         24 . A method of pumping fluid into a wellbore, comprising:
 drawing a fluid through an intake valve of the pump of  claim 11  by moving said plunger through an intake stroke;   moving said plunger through a discharge stroke, thereby pressurizing fluid in said chamber, closing said intake valve and opening said discharge valve and forcing said fluid through said discharge valve into said wellbore.   
     
     
         25 . A method of pumping fluid into a wellbore, comprising:
 drawing a fluid through an intake valve of the pump of  claim 16  by moving said plunger through an intake stroke;   moving said plunger through a discharge stroke, thereby pressurizing fluid in said chamber, closing said intake valve and opening said discharge valve and forcing said fluid through said discharge valve into said wellbore.