Enhancing hydrocarbon recovery

Abstract

Recovery of hydrocarbon fluid from low permeability sources is enhanced by introduction of a treating fluid. The treating fluid may include one or more constituent ingredients designed to cause displacement of hydrocarbon via imbibition. The constituent ingredients may be determined based on estimates of formation wettability. Further, contact angle may be used to determine wettability. Types and concentrations of constituent ingredients such as surfactants may be determined for achieving the enhanced recovery of hydrocarbons.

1 . A method for enhancing hydrocarbon recovery from a low permeability source comprising:
 causing a treating fluid to contact the source such that the treating fluid is imbibed by the source, thereby increasing hydrocarbon recovery,   wherein the source is characterized by matrix permeability less than 0.2 milliDarcies (mD).   
   
   
       2 . The method of  claim 1 , further comprising:
 estimating source wettability;   determining constituents of said treating fluid based on said estimated source wettability;   formulating said treating fluid using said determined constituents.   
   
   
       3 . The method of  claim 1  wherein estimating source wettability includes estimating a contact angle. 
   
   
       4 . The method of  claim 1  wherein the recovered hydrocarbon comprises a gas or a supercritical fluid. 
   
   
       5 . The method of  claim 4  wherein said source has a reservoir matrix permeability of less than 0.1 mD. 
   
   
       6 . The method of  claim 1  wherein the recovered hydrocarbon comprises an oil or a condensate. 
   
   
       7 . The method of  claim 6  wherein said source has a reservoir matrix permeability of less than 0.01 mD. 
   
   
       8 . The method of  claim 1  wherein determining treating fluid constituents includes selecting at least one constituent selected from the group which includes scale inhibitors, formation stabilizers, e.g., fines stabilizers and clay stabilizers, oxygen scavengers, antioxidants, iron control agents, corrosion inhibitors, emulsifiers, demulsifiers, foaming agents, anti-foaming agents, buffers, pH adjusters and other additives that will alter the available surface area. 
   
   
       9 . The method of  claim 8  including determining a surfactant type and concentration to achieve the desired imbibition in order to increase hydrocarbon recovery. 
   
   
       10 . The method of  claim 1  wherein said treating fluid includes an anti-bacterial or biocidal agent. 
   
   
       11 . The method of  claim 1  wherein said treating fluid includes a constituent that results in surface tension of said treating fluid changing over time. 
   
   
       12 . The method of  claim 1  wherein said treating fluid includes a constituent that causes surface tension of said treating fluid to change in response to a temperature change. 
   
   
       13 . The method of  claim 1 , wherein said treating fluid is placed into contact with the source and hydrocarbon is recovered through the same wellbore. 
   
   
       14 . The method of  claim 1 , wherein said treating fluid is placed into contact with the source and hydrocarbon is recovered through different wellbores. 
   
   
       15 . Apparatus for enhancing hydrocarbon recovery from a low permeability source comprising:
 a container that stores a treating fluid, said treating fluid characterized by one or more constituents that facilitate imbibition;   a fluid transfer device that transfers said treating fluid from said container to the source; and   a conduit that recovers hydrocarbons released from the source due to imbibition of said treating fluid,   wherein the source is characterized by matrix permeability less than 0.2 milliDarcies (mD).   
   
   
       16 . An apparatus in accordance with  claim 15 , wherein said treating fluid comprises one or more constituents selected based on estimates of source wettability. 
   
   
       17 . The apparatus of  claim 15  wherein the estimate of source wettability includes an estimate of contact angle. 
   
   
       18 . The apparatus of  claim 15  wherein the recovered hydrocarbon comprises a gas or a supercritical fluid. 
   
   
       19 . The apparatus of  claim 18  wherein said source has a reservoir matrix permeability of less than 0.1 mD. 
   
   
       20 . The apparatus of  claim 15  wherein the recovered hydrocarbon comprises an oil or a condensate. 
   
   
       21 . The apparatus of  claim 20  wherein said source has a reservoir matrix permeability of less than 0.01 mD. 
   
   
       22 . The apparatus of  claim 15  wherein said treating fluid includes at least one constituent selected from the group which includes scale inhibitors, source stabilizers, and surface area modifiers. 
   
   
       23 . The apparatus of  claim 15  wherein said treating fluid includes at least one surfactant having a type and concentration required to achieve improved hydrocarbon recovery. 
   
   
       24 . The apparatus of  claim 15  wherein the treating fluid includes an anti-bacterial or biocidal agent. 
   
   
       25 . The apparatus of  claim 23  wherein the treating fluid includes a constituent that results in the surface tension changing over time. 
   
   
       26 . The apparatus of  claim 23  wherein the treating fluid includes a constituent that causes surface tension to change in response to a temperature change. 
   
   
       27 . The apparatus of  claim 15 , wherein said treating fluid is transferred and said hydrocarbon is recovered through the same wellbore. 
   
   
       28 . The apparatus of  claim 15 , wherein said treating fluid is transferred and said hydrocarbon is recovered through different wellbores.