Method and apparatus for stimulating a subterranean formation using liquefied natural gas

Abstract

Liquefied natural gas is used as a fracturing fluid to stimulate production of hydrocarbons from and/or injectability of fluids into subterranean formations. Proppants may be blended with the LNG prior to pumping the liquefied natural gas into the well. Optionally, the liquefied natural gas is heated after it is pumped and before it is introduced into the subterranean formation.

1 . A fracturing fluid for stimulating hydrocarbon production from a subterranean formation, the fracturing fluid comprising liquefied natural gas.  
   
   
       2 . The fracturing fluid as claimed in  claim 1  further comprising a proppant carried by the liquefied natural gas.  
   
   
       3 . The fracturing fluid as claimed in  claim 2  wherein the proppant comprises sand.  
   
   
       4 . The fracturing fluid as claimed in  claim 2  wherein the proppant is sintered bauxite.  
   
   
       5 . The fracturing fluid as claimed in  claim 2  wherein the proppant is a ceramic particulate.  
   
   
       6 . A method of stimulating a subterranean formation to increase hydrocarbon production from the subterranean formation, the method comprising: 
 drawing liquefied natural gas from a liquefied natural gas source;    pumping the liquefied natural gas at a pressure and a flow rate high enough to induce fracturing of the subterranean formation; and    conducting the natural gas into the subterranean formation.    
   
   
       7 . The method as claimed in  claim 6  further comprising an initial step of cooling and pressure testing at least pumps used for the pumping and conduits used for conducting the liquefied natural gas to the subterranean formation using an inert fluid prior to pumping the liquefied natural gas.  
   
   
       8 . The method as claimed in  claim 7  wherein the inert fluid is nitrogen.  
   
   
       9 . The method as claimed in  claim 6  further comprising blending a solid particulate with the liquefied natural gas before it is pumped.  
   
   
       10 . The method as claimed in  claim 6  wherein the subterranean formation comprises a natural gas well.  
   
   
       11 . The method as claimed in  claim 6  wherein the subterranean formation comprises an oil well.  
   
   
       12 . The method as claimed in  claim 6  wherein the subterranean formation comprises a coal bed seam.  
   
   
       13 . The method as claimed in  claim 6  wherein the subterranean formation comprises a storage cavern or permeable strata.  
   
   
       14 . The method as claimed in  claim 6  wherein the subterranean formation comprises an aquifer.  
   
   
       15 . The method as claimed in  claim 6  wherein the subterranean formation comprises shale.  
   
   
       16 . The method as claimed in  claim 6  wherein the subterranean formation comprises a tar sand.  
   
   
       17 . A method of stimulating a subterranean formation to increase hydrocarbon production from the subterranean formation, the method comprising: 
 drawing liquefied natural gas from a liquefied natural gas source;    pumping the liquefied natural gas at a pressure and a flow rate high enough to induce fracturing of the subterranean formation;    heating the liquefied natural gas while it is being pumped down the well; and    conducting the natural gas into the subterranean formation.    
   
   
       18 . The method as claimed in  claim 17  wherein the heating comprises routing the liquefied natural gas through a gas boiler.  
   
   
       19 . The method as claimed in  claim 17  wherein the heating comprises laying a conduit for conducting the liquefied natural gas in a large body of water, the conduit being connected on one end to cryogenic pumps for the pumping the liquid natural gas and on the other end to wellhead isolation equipment connected to a wellhead of the well bore that communicates with the subterranean formation, whereby the large body of water provides ambient heat to convert the liquefied natural gas to the compressed natural gas as it is pumped to the subterranean formation.  
   
   
       20 . The method as claimed in  claim 17  wherein the heating comprises circulating a heating fluid through an annulus that surrounds a tubular used to conduct the liquefied natural gas to the subterranean formation.  
   
   
       21 . The method as claimed in  claim 17  wherein the subterranean formation comprises a natural gas well.  
   
   
       22 . The method as claimed in  claim 17  wherein the subterranean formation comprises an oil well.  
   
   
       23 . The method as claimed in  claim 17  wherein the subterranean formation comprises a coal bed seam.  
   
   
       24 . The method as claimed in  claim 17  wherein the subterranean formation comprises a storage cavern or permeable stratum.  
   
   
       25 . The method as claimed in  claim 17  wherein the subterranean formation comprises an aquifer.  
   
   
       26 . The method as claimed in  claim 17  wherein the subterranean formation comprises a shale.  
   
   
       27 . The method as claimed in  claim 17  wherein the subterranean formation comprises a tar sand.  
   
   
       28 . A method of fracturing a well to stimulate production or injectability, comprising: 
 connecting wellhead isolation equipment to a wellhead of the a well;    pumping liquefied natural gas down through a tubular connected to the wellhead isolation equipment and suspended in the well to a subterranean formation at a pressure and a flow rate adequate to induce fracturing in the subterranean formation;    removing the wellhead isolation equipment and connecting hydrocarbon production equipment to the wellhead; and    producing hydrocarbons from the well to recover the natural gas and produce the hydrocarbons from the subterranean formation.    
   
   
       29 . The method as claimed in  claim 28  wherein prior to pumping the liquefied natural gas into the subterranean formation the method further comprises pumping an inert cryogenic fluid through the wellhead isolation equipment and the tubular to pressure test and pre-cool the wellhead isolation equipment and the tubular.  
   
   
       30 . The method as claimed in  claim 28  wherein prior to pumping the liquefied natural gas into the subterranean formation the method further comprises pumping an inert cryogenic fluid through the surface pumping equipment and surface fracture conduits, chicksans, and manifolds, to pressure test and pre-cool that surface equipment.  
   
   
       31 . The method as claimed in  claim 28  wherein prior to pumping the liquefied natural gas into the subterranean formation the method further comprises pumping an inert cryogenic fluid through well system tubulars to pressure test and pre-cool the well system.  
   
   
       32 . The method as claimed in  claim 28  further comprising blending proppant with the liquefied natural gas.  
   
   
       33 . The method as claimed in  claim 28  further comprising blending proppant with the liquefied natural gas prior to the pumping.  
   
   
       34 . The method as claimed in  claim 28  wherein the subterranean formation comprises a natural gas well.  
   
   
       35 . The method as claimed in  claim 28  wherein the subterranean formation comprises an oil well.  
   
   
       36 . The method as claimed in  claim 28  wherein the subterranean formation comprises a coal bed seam.  
   
   
       37 . The method as claimed in  claim 28  wherein the subterranean formation comprises a storage cavern or permeable strata.  
   
   
       38 . The method as claimed in  claim 28  wherein the subterranean formation comprises an aquifer.  
   
   
       39 . The method as claimed in  claim 28  wherein the subterranean formation comprises a shale.  
   
   
       40 . The method as claimed in  claim 28  wherein the subterranean formation comprises a tar sand.  
   
   
       41 . A method of fracturing a well to stimulate at least one of production of fluids and injectability of fluids, comprising the steps of: 
 connecting wellhead isolation equipment to a wellhead of the well;    pumping liquefied natural gas through a heat exchanger in fluid communication with the wellhead isolation equipment and a subterranean formation of the well at a pressure and a flow rate adequate to induce fracturing in the subterranean formation;    removing the wellhead isolation equipment and connecting hydrocarbon production equipment to the wellhead; and    producing hydrocarbons from the well to recover the natural gas and produce the hydrocarbons from the subterranean formation.    
   
   
       42 . The method as claimed in  claim 41  further comprising blending proppants with the liquefied natural gas prior to the pumping.  
   
   
       43 . The method as claimed in  claim 41  wherein the heat exchanger comprises a methane boiler.  
   
   
       44 . The method as claimed in  claim 41  wherein the heat exchanger comprises a tubular in a large body of water.  
   
   
       45 . The method as claimed in  claim 41  wherein the heat exchanger comprises an annulus surrounding a tubular connected to the wellhead isolation equipment and the method further comprises circulating a heating fluid through the annulus.  
   
   
       46 . The method as claimed in  claim 41  wherein the subterranean formation comprises a natural gas well.  
   
   
       47 . The method as claimed in  claim 41  wherein the subterranean formation comprises an oil well.  
   
   
       48 . The method as claimed in  claim 41  wherein the subterranean formation comprises a coal bed seam.  
   
   
       49 . The method as claimed in  claim 41  wherein the subterranean formation comprises an aquifer.  
   
   
       50 . The method as claimed in  claim 41  wherein the subterranean formation comprises a shale.  
   
   
       51 . The method as claimed in  claim 41  wherein the subterranean formation comprises a tar sand.  
   
   
       52 . A fracturing fluid for stimulating a subterranean formation, the fracturing fluid comprising liquefied methane.  
   
   
       53 . A method of stimulating a subterranean formation to increase the rate of fluid injectability of a subterranean formation, the method comprising: 
 drawing liquefied natural gas from a liquefied natural gas source;    pumping the liquefied natural gas at a pressure and a flow rate high enough to induce fracturing of the subterranean formation; and    conducting the liquefied natural gas into the subterranean formation.    
   
   
       54 . A method of fracturing a well to stimulate production or injectability of a subterranean formation, comprising: 
 connecting wellhead isolation equipment to a wellhead of the a well;    pumping liquefied natural gas down through a cryogenically compatible tubular connected to the wellhead isolation equipment and suspended in the well to a subterranean formation at a pressure and a flow rate adequate to induce fracturing in the subterranean formation;    maintaining the wellhead isolation equipment, cryogenically compatible tubulars, insulated pipes, and cooling conduits, connected at the well site and in the well system to permit periodic injection of liquefied natural gas into the well.