Methods and apparatus for storage and recovery of hydrocarbon fluids

Abstract

A hydrocarbon strategic reserve method comprises operating production wells deployed in a post-pyrolysis oil shale formation at significantly elevated wellhead pressures for an extended period of time so as to store hot hydrocarbon fluids within pore space thereof. In some embodiments, the hydrocarbon fluids are stored at a depth of at least 100 meters or at least 200 meters or at least 300 meters. In some embodiments, the hydrocarbon fluids are stored substantially at or above bubble point curve thereof.

What is claimed is: 
     
         1 . A hydrocarbon strategic reserve method comprising:
 operating production wells deployed in a post-pyrolysis oil shale formation at significantly elevated wellhead pressures for an extended period of time so as to store hot hydrocarbon fluids within pore space thereof, the hydrocarbon fluids being stored (i) at a depth of at least 100 meters or at least 200 meters or at least 300 meters and/or (ii) substantially at or above bubble point curve of the hydrocarbon fluids.   
     
     
         2 . The method of any preceding claim wherein the stored hydrocarbon fluids include and/or are primarily unhydrotreated fluids. 
     
     
         3 . The method of any preceding claim wherein the stored hydrocarbon fluids are primarily C7+ hydrocarbon fluids. 
     
     
         4 . The method of any preceding claim wherein the stored hydrocarbon fluids are primarily native C7+ pyrolysis fluids derived from the oil shale formation and stored in situ therein. 
     
     
         5 . The method of any preceding claim wherein the stored hydrocarbon fluids comprise a stabilized unhydrotreated synthetic condensate (SUCS) derived from pyrolysis fluids. 
     
     
         6 . The method of any preceding claim wherein the stored hydrocarbon fluids include external hydrocarbon fluids that are injected into pore space of the post-pyrolysis oil shale formation after pyrolysis thereof. 
     
     
         7 . The method of any preceding claim wherein the external hydrocarbon fluids include methane. 
     
     
         8 . The method of any preceding claim wherein the stored hydrocarbon fluids are native C7+ pyrolysis fluids derived from the oil shale formation and stored in situ therein, wherein the production wells are dual phase production wells, and wherein the method further comprises:
 upon pyroylsis of the oil shale formation, operating the production wells therein at the significantly elevated wellhead pressure so that primarily aqueous pyrolysis liquids are recovered by pumping through production tubulars of the production wells while pyrolysis gases are recovered via an annular section of the production wells.   
     
     
         9 . The method of any preceding claim wherein the production wells are operated for the extended period of time at a governing wellhead pressure of at least 20 atmospheres, or at least 30 atmospheres, or at least 40 atmospheres, or at least 50 atmospheres, or at least 60 atmospheres. 
     
     
         10 . The method of any preceding claim wherein the hot hydrocarbon fluids are stored at a depth of at least 100 meters, or at least 300 meters, or at least 350 meters, or at least 400 meters. 
     
     
         11 . The method of any preceding claim wherein the hot hydrocarbon fluids are stored for the extended period of time comprise primarily C7+ hydrocarbon fluids, or primarily C8+ hydrocarbon fluids. 
     
     
         12 . The method of any preceding claim wherein the hot hydrocarbon fluids are stored for the extended period of time substantially at or above bubble point curve thereof. 
     
     
         13 . The method of any preceding claim wherein a temperature of the hot hydrocarbon fluids is at least 160 degrees, or at least 180 degrees, or at least 200 degrees, or at least 250 degrees, or at least 275 degrees, or at least 300 degrees. 
     
     
         14 . The method of any preceding claim wherein the target portion has a length, width, and height of at least 100 meters. 
     
     
         15 . The method of any preceding claim wherein the hot hydrocarbon fluids are stored for the extended period of time substantially throughout an entirety of the target portion. 
     
     
         16 . A method of creating a hydrocarbon strategic reserve of hydrocarbon fluids within an oil shale formation, the method comprising:
 operating the subsurface heaters so to pyrolyze, by an in situ thermal process, a significant portion of the oil shale formation; and   operating the production wells so as to recover, in the liquid phase, a majority of the aqueous pyrolysis formation fluids of the significant portion of the oil shale formation while substantially all of the C7+ pyrolysis formation fluids of the pyrolyzed significant portion remain in the pore space thereof.   
     
     
         17 . The method of  claim 16  wherein the majority of the aqueous pyrolysis formation fluids of the significant portion of the oil shale formation are recovered by pumping. 
     
     
         18 . The method of  claim 16  wherein the majority of the aqueous pyrolysis formation fluids of the significant portion of the oil shale formation are recovered by pumping through a production tubular of a dual-phase production well. 
     
     
         19 . The method of any of  claims 16 - 18  wherein a downhole separator is maintained at or near the production well. 
     
     
         20 . The method of any of  claims 16 - 19  wherein a cold sump is maintained at or near the production well. 
     
     
         21 . A method of creating and maintaining a hydrocarbon strategic reserve, the method comprising:
 a. during a pyrolysis phase, operating subsurface heaters so as to pyrolyze, by an in situ thermal process, a target portion of an oil shale formation having a depth of at least 100 meters or at least 200 meters or at least 300 meters, thereby converting organic matter therein into hot pyrolysis fluids; and   b. during a storage phase and after a majority of the organic matter has been converted into hot pyrolysis fluids, storing a majority of the hot pyrolysis fluids within the pore space of the target portion for an extended period of time, wherein during substantial entireties of each of the pyrolysis and storage phases, the target portion is maintained at a wellhead pressure of at least 20 atmospheres, or at least 30 atmospheres, or at least 40 atmospheres, or at least 50 atmospheres, or at least 60 atmospheres.   
     
     
         22 . A method of creating and maintaining a hydrocarbon strategic reserve within an oil shale formation, the method comprising:
 a. pyrolyzing organic matter of a first oil shale target region into pyrolysis fluids   b. producing the pyrolysis fluids via multi-phase production wells;   c. forming a stabilized unhydrotreated synthetic condensate (SUSC) from the produced pyrolysis fluids by separating therefrom (i) water, (ii) light hydrocarbon fractions and (iii) light sulfur-containing molecules;   d. introducing the hydrocarbon fluid comprising or derived from the SUSC into a second oil shale target region that is hot, previously pyrolyzed and non-communicating with the first oil shale target region so that the introduced hydrocarbon fluid resides within pore space of the second oil shale target region; and   e. operating production wells within the second oil shale target region at an elevated pressure so as to store the introduced hydrocarbon fluid for an extended period of time as a hot fluid and substantially at or above its bubble point curve.   
     
     
         23 . The method or system of any previous claim wherein the wellhead pressure is maintained (i) at or above 30 atmospheres during substantial entireties of the pyrolyzing and the storing; or (ii) at or above 40 atmospheres during substantial entireties of the pyrolyzing and the storing; or (iii) at or above 50 atmospheres during substantial entireties of the pyrolyzing and the storing; or (iv) at or above 60 atmospheres during substantial entireties of the pyrolyzing and the storing. 
     
     
         24 . The method or system of any previous claim wherein a depth of the target portion is at least 200 meters or at least 300 meters, or at least 350 meters, or at least 400 meters. 
     
     
         25 . The method or system of any preceding claim wherein a molar majority of the hot hydrocarbon pyrolysis fluids stored for the extended period of time are C7+ pyrolysis fluids. 
     
     
         26 . The method or system of any preceding claim wherein a temperature of the extended-period-stored hot hydrocarbon pyrolysis fluids equals or exceeds 250 degrees Celsius. 
     
     
         27 . The method or system of any preceding claim wherein a significant fraction of the organic matter of the target portion is pyrolyzed into the hydrocarbon pyrolysis fluids which are stored within the target portion for the extended period of time. 
     
     
         28 . The method or system of any preceding claim wherein a majority, by mass, of the organic matter of the target portion is pyrolyzed into the hydrocarbon pyrolysis fluids which are stored within the target portion for extended period of time. 
     
     
         29 . The method of any preceding claim wherein the target portion has a length, width, and height of at least 50 meters, or at least 100 meters. 
     
     
         30 . The method or system of any preceding claim wherein the formed hydrocarbon pyrolysis fluids are stored for the extended period of time substantially throughout an entirety of the target portion. 
     
     
         31 . The method or system of any preceding claim wherein a majority of the stored hydrocarbon pyrolysis fluids remain within the target portion at the depth of at least 250 meters during entireties of the pyrolyzing, the storing and in the interim. 
     
     
         32 . The method or system of any preceding claim wherein substantially all of the stored hydrocarbon pyrolysis fluids remain within the target portion at the depth of at least 250 meters during entireties of the pyrolyzing, the storing and in the interim. 
     
     
         33 . A method of creating and maintaining a hydrocarbon strategic reserve within an oil shale formation, the method comprising:
 a. pyrolyzing organic matter of first oil shale target region into pyrolysis fluids comprising steam and vapor-phase hydrocarbons;   b. producing the pyrolysis fluids via production wells;   c. cooling and separating the pyrolysis fluids into hydrocarbon and aqueous condensates; and   d. introducing a hydrocarbon fluid comprising the hydrocarbon condensate or a hydrocarbon derivative thereof into a hot second oil shale target region that is pre-pyrolyzed and significantly horizontally displaced from the first oil shale target region so that the introduced hydrocarbon fluid resides within pore space of the second oil shale target region at a depth of at least 100 meters or at least 200 meters or at least 300 meters.   
     
     
         34 . The method or system of any of preceding claim wherein the introduced hydrocarbon fluid is heated by latent heat of the pre-pyrolyzed second oil shale target region to at least 250 degrees. 
     
     
         35 . The method or system of any preceding claim further comprising storing the introduced hydrocarbon fluid within pore space of the second oil shale target region at the depth of at least 250 meters for an extended period of time. 
     
     
         36 . The method or system of any preceding claim wherein the introduced hydrocarbon fluid is heated by latent heat of the pre-pyrolyzed second oil shale target region to at least 250 degrees. 
     
     
         37 . The method or system of any previous claim wherein the introduced hydrocarbon fluids is stored for the extended period of time in the pore space of the second oil shale target region substantially at or above bubble point curve conditions. 
     
     
         38 . The method or system of any preceding claim wherein during storage, the hot hydrocarbon fluids within the pore space of the post-pyrolysis formation, have a viscosity of at most 1 cP, or at most 0.5 cP. 
     
     
         39 . The method or system of any preceding claim wherein a length, width and height of the target portion is at least 50 meters, and the hot hydrocarbon fluids are stored throughout substantially an entirety of the target portion. 
     
     
         40 . The method or system of any preceding claim wherein during substantially an entirety of the storage phase, throughout substantially an entirety of the target portion, the hot C7+ pyrolysis fluids are stably stored primarily as a liquid. 
     
     
         41 . The method or system of any preceding claim wherein after pyrolysis the target portion has a pyrolyzed porosity of at least 30%, or at least 40% or at least 45% or at least 50%.