Method for Hydraulically Fracturing a Well Using A Frac Water Heater

Abstract

The present invention overcomes many of the disadvantages of prior art mobile oil field heat exchange systems by providing a portable heat exchange system. The present invention is a self-contained unit which is easily transported to remote locations. The present invention includes a single-pass tubular coil heat exchanger contained within a closed-bottom firebox having a forced-air combustion and cooling system. The rig also includes integral fuel tanks, hydraulic and pneumatic systems for operating the rig at remote operations in all weather environments. In a preferred embodiment, the portable heat exchanger system is used to heat water on-the-fly (i.e., directly from the supply source to the well head) to complete hydraulic fracturing operations. The present invention also includes systems for regulating and adjusting the fuel/air mixture within the firebox to maximize the combustion efficiency. The system includes a novel hood opening mechanism attached to the exhaust stack of the firebox.

I claim: 
     
         1 . A method of fracturing a subterranean formation at a remote work site to produce at least one of oil and gas, comprising the steps of:
 a) providing a portable heating system for heating treatment fluid, said heating system comprising a heat exchanger having a tubular coil featuring a single inlet and a single outlet;   b) drawing treatment fluid from a fluid source to said inlet of said heat exchanger in said portable heating system;   c) pumping said treatment fluid through a single pass of said heat exchanger in said portable heating system;   d) heating said treatment fluid during said single pass through said heat exchanger by combusting an air-fuel mixture in said firebox using a plurality of burner assemblies;   e) directing the heated treatment fluid from said outlet of said heat exchanger directly to a well head at said work site for injection into the formation.   
     
     
         2 . The method of  claim 1 , wherein said treatment fluid flows substantially continuously from said inlet to the outlet to the well head during the fracturing process. 
     
     
         3 . The method of  claim 2 , wherein said treatment fluid flows at a substantially constant volumetric rate from said inlet to the outlet to the well head during the fracturing process. 
     
     
         4 . The method of  claim 1 , wherein step e) further comprises adding chemical additives to the heated treatment fluid prior to injection into the formation. 
     
     
         5 . The method of  claim 4 , wherein said chemical additives comprise friction reducer polymers, which reduce the viscosity of the heated treatment fluid. 
     
     
         6 . The method of  claim 1 , wherein step e) further comprises adding proppants to the heated treatment fluid prior to injection into the formation. 
     
     
         7 . The method of  claim 6 , wherein step e) further comprises adding a cross-linked guar gel. 
     
     
         8 . The method of  claim 1 , wherein step e) further comprises adding chemical additives and proppants to the heated treatment fluid prior to injection into the formation. 
     
     
         9 . The method of  claim 8 , wherein step e) further comprises adding a cross-linked guar gel. 
     
     
         10 . The method of  claim 1 , wherein said treatment fluid is heated to at least 70° F. while pumping through said heat exchanger at a volumetric flow rate of at least 200 gpm. 
     
     
         11 . The method of  claim 10 , wherein said treatment fluid is heated to between 70° F.-210° F. while pumping through said heat exchanger at a volumetric flow rate of at least 200 gpm. 
     
     
         12 . The method of  claim 1 , wherein said treatment fluid is heated to at least 40° F. in ambient atmospheric temperatures below 25° F. while pumping through said heat exchanger at a volumetric flow rate ranging from at least 200 gpm. 
     
     
         13 . The method of  claim 12 , wherein said treatment fluid is heated to between 40° F.-210° F. in ambient atmospheric temperatures below 25° F. while pumping through said heat exchanger at a volumetric flow rate ranging from 200-250 gpm. 
     
     
         14 . The method of  claim 1 , wherein the step of drawing treatment fluid from said fluid source includes activating a hydraulically-powered centrifugal fluid pump integral to said portable heating system and in fluid communication with and configured between said fluid source and said inlet of said heat exchanger in said portable heating system. 
     
     
         15 . The method of  claim 1 , wherein said treatment fluid is water. 
     
     
         16 . The method of  claim 1 , wherein the volumetric rate at which treatment fluid is drawn from said fluid source in step b) substantially equals the volumetric rate of heated treatment fluid that is directed from the outlet directly to the well head in step e). 
     
     
         17 . The method of  claim 1 , wherein the volume of treatment fluid drawn from said fluid source in step b) is substantially equal to the volume of heated treatment fluid directed from the outlet directly to the well head in step b). 
     
     
         18 . The method of  claim 1 , wherein the inlet of said portable heating system further comprises a manifold having one or more spigots for receiving supply hose in fluid communication with said fluid source. 
     
     
         19 . The method of  claim 1 , wherein the outlet of said portable heating system further comprises a manifold having one or more spigots for connecting to supply hose in fluid communication with said well head.