High pressure multistage centrifugal pump for fracturing hydrocarbon reserves

Abstract

The present invention relates to a multistage centrifugal pump design, which has the diffusers, impellors, and a shaft, inserted within a high pressure housing, such that this assembly is fully enclosed within the housing, and the housing is of sufficient strength to be suitable for safe pressure containment of the fluids being pumped. This invention describes the technical details used to reconfigure the multistage centrifugal pump design to increase the discharge pressure capabilities higher than the 6,000 psig of current designs.

What is claimed is: 
     
         1 . A method for hydraulically fracturing an underground hydrocarbon deposit comprising:
 using an underground aquifer as a source of water for a hydrocarbon fracturing process, the water containing undesirable chemical compounds as soluble components that are not in solution when subjected to pressure at atmospheric conditions;   pumping the water under pressure at a predetermined level for the aquifer water and above a bubble point pressure for the water contained in the aquifer to prevent the undesirable chemical compounds in the water from separating out of solution;   maintaining the water pressure above the bubble point pressure during a fracturing operation;   drilling a source well into the aquifer;   drilling a disposal well into the aquifer;   pumping the water within a closed loop to maintain the water above the bubble point pressure;   circulating the water until a fracturing operation begins; and   conducting the fracturing operation with water from the underground aquifer to fracture the hydrocarbon deposit, wherein the water is maintained above its bubble point pressure, said water remains stable and the undesirable chemical compounds remain in solution.   
     
     
         2 . The method of  claim 1 , wherein:
 the water remains clear during said conducting step.   
     
     
         3 . The method of  claim 1  wherein:
 fracturing is conducted for a shale gas deposit. 
 
     
     
         4 . The method of  claim 1 , wherein:
 the water includes hydrogen sulfide, and pumping of the water under pressure and above the bubble point pressure prevents the hydrogen sulfide from separating out of solution.   
     
     
         5 . The method of  claim 1 , further comprising:
 establishing a closed loop circulation during said circulating step by use of a manifold, or a manifold and at least one pump to keep the water circulating until conducting the fracturing.   
     
     
         6 . The method of  claim 1  further including;
 providing at least one source well and at least one disposal water well enabling fracturing to occur on demand for each pad of a predetermined number of pads. 
 
     
     
         7 . The method of  claim 1  wherein:
 the water from the aquifer is kept at an elevated temperature in relation to ambient surface water. 
 
     
     
         8 . The method of  claim 5  further comprising:
 providing an underground pipeline including a water circulation line and a back pressure control valve located in the water circulation line, wherein the pipeline communicates with the manifold or the manifold and at least one pump, such that water can be withdrawn from the manifold or the manifold and at least one pump. 
 
     
     
         9 . The method of  claim 1  further comprising:
 providing a high pressure blender to maintain the water above its bubble point pressure. 
 
     
     
         10 . A method for hydraulically fracturing an underground hydrocarbon deposit comprising:
 using an underground aquifer as a source of water for a hydrocarbon fracturing process, the water containing undesirable chemical compounds as soluble components that are not in solution when subjected to pressure at atmospheric conditions;   pumping the water under pressure at a predetermined level for the aquifer water and above a bubble point pressure for the water contained in the aquifer to prevent the undesirable chemical compounds in the water from separating out of solution;   maintaining the water pressure above the bubble point pressure during a fracturing operation by pumping the water with a multiple stage centrifugal pump, the pump including (i) a pump base, (ii) a pump head, (iii) a metal on metal housing seal located between the pump base, and pump head, and (iv) a plurality of diffusers having openings to allow rapid pressure equalization across a diffuser outside edge to avoid failure from high differential pressure, each diffuser having a seal located on an outside portion of each of the diffusers to prevent pressure communication and fluid flow between the outsides of the individual diffusers enclosed within the housing;   circulating the water until a fracturing operation begins; and   conducting the fracturing operation with water from the underground aquifer to fracture the hydrocarbon deposit, wherein the water is maintained above its bubble point pressure, said water remains stable and the undesirable chemical compounds remain in solution.   
     
     
         11 . A method of  claim 10 , further comprising:
 drilling a source well into the aquifer;   drilling a disposal well into the aquifer; and   pumping the water within a closed loop to maintain the water above the bubble point pressure.   
     
     
         12 . A method of  claim 10 , wherein:
 pump connections of said pump for pump intake and discharge include ring or gasket sealing, and wherein said pump delivers a discharge pressure or differential pressure between the pump internal and external pressure of up to substantially 10,000 psi or over.   
     
     
         13 . A method of maintaining adequate pressure in hydraulic fracturing of an underground hydrocarbon deposit comprising:
 maintaining water pressure for water in an underground aquifer used in a fracturing operation above a bubble point pressure for the water during the fracturing operation by pumping the water with a multiple stage centrifugal pump, the pump including (i) a pump base (ii) a pump head (iii) a housing including a housing seal located between the pump base and pump head (iv) a plurality of rotating impellors and (v) a plurality of stationary diffusers each having openings to allow rapid pressure equalization across a diffuser outside edge to avoid failure from high differential pressure, each diffuser further having a seal located to an outside portion of each of the diffusers to prevent pressure communication and fluid flow between the outsides of the individual diffusers enclosed within the housing.   
     
     
         14 . A method of  claim 13 , wherein:
 the housing seal includes a metal on metal type housing seal.   
     
     
         15 . A method of  claim 13 , wherein:
 pump connections of the pump used for pump intake and discharge include ring or gasket sealing, and wherein the pump delivers a discharge pressure or differential pressure between the pump internal and external pressure of up to 10,000 psi or over.   
     
     
         16 . A method, as claimed in  claim 13 , wherein:
 the pump further includes a pressure sleeve secured to an outside wall of each of said diffusers by a compression fit to prevent deformation of the diffusers during operation of the pump.   
     
     
         17 . A multistage high pressure centrifugal pump comprising:
 a pump base;   a pump head;   a housing including a housing seal located between the pump base and pump head;   a pump shaft disposed in the housing; and   a plurality of pump stages mounted along the pump shaft in series, each pump stage including a rotating impellor mounted on the pump shaft and a stationary diffuser having an opening to allow rapid pressure equalization across an outside edge of the diffuser to avoid failure from high differential pressure, wherein   
     
     
         18 . A multistage high pressure centrifugal pump according to  claim 17 , wherein:
 each diffuser is fixed in the pump by a compression bearing seated against the pump base.   
     
     
         19 . A multistage high pressure centrifugal pump according to  claim 17 , wherein:
 each diffuser further includes a diffuser seal located on an outside portion of the diffuser to prevent pressure communication and fluid flow between the outsides of the individual diffusers enclosed within the housing.   
     
     
         20 . A multistage high pressure centrifugal pump according to  claim 17 , wherein:
 the opening of the diffuser is an equalization hole extending radially outward from a longitudinal axis of the pump housing.   
     
     
         21 . A multistage high pressure centrifugal pump according to  claim 17 , wherein:
 pump connections connected to the pump and used for pump intake and discharge include ring or gasket sealing, and wherein the pump delivers a discharge pressure or differential pressure between the pump internal and external pressure of up to 10,000 psi or over.   
     
     
         22 . A multistage high pressure centrifugal pump according to  claim 17 , further including:
 a pressure sleeve secured to an outside wall of each of said diffusers by a compression fit to prevent deformation of the diffusers during operation of the pump.   
     
     
         23 . A multistage high pressure centrifugal pump according to  claim 22 , wherein:
 the diffuser seal includes a groove formed on the pressure sleeve for each stage, and an o-ring sated in the groove.