Remediation of asphaltene-induced plugging of an oil-bearing formation

Abstract

A system and method for remediation of asphaltene-induced fouling of an oil-bearing formation is provided wherein an asphaltene solvent comprising at least 75 mol % dimethyl sulfide is introduced into an oil-bearing formation containing asphaltene deposits and the dimethyl sulfide is contacted with the asphaltene deposits.

What is claimed: 
     
         1 . A method for remediating asphaltene deposition in an oil-bearing formation, comprising:
 providing an asphaltene solvent comprising at least 75 mol % dimethyl sulfide (DMS);   introducing the asphaltene solvent into an oil-bearing formation containing one or more asphaltene deposits; and   contacting the asphaltene solvent with one or more of the asphaltene deposits in the formation.   
     
     
         2 . The method of  claim 1  further comprising producing the asphaltene solvent from the formation after introducing the asphaltene solvent into the formation. 
     
     
         3 . The method of  claim 1  further comprising producing oil from the formation after introducing the asphaltene solvent into the formation. 
     
     
         4 . The method of  claim 1  wherein the asphaltene solvent is introduced into the formation through a first well. 
     
     
         5 . The method of  claim 4  further comprising producing oil from the formation through the first well after introducing the asphaltene solvent into the formation through the first well. 
     
     
         6 . The method of  claim 4  wherein the asphaltene deposits are located in the formation within 5 meters of the first well. 
     
     
         7 . The method of  claim 6  wherein a volume of solvent sufficient to penetrate up to 5 meters radially from the first well is introduced into the formation through the first well. 
     
     
         8 . The method of  claim 4  further comprising producing oil from the formation through a second well after introducing the asphaltene solvent into the formation through the first well. 
     
     
         9 . The method of  claim 8  where from 0.1 to 2 pore volumes of the asphaltene solvent are introduced into the formation through the first well. 
     
     
         10 . The method of  claim 1  wherein one or more of the asphaltene deposits form a tar mat in the formation. 
     
     
         11 . The method of  claim 10  wherein the first well is located in the formation within 10 meters of the tar mat. 
     
     
         12 . The method of  claim 1  wherein the asphaltene solvent is first contact miscible with oil in or from the formation. 
     
     
         13 . The method of  claim 1  wherein the asphaltene solvent consists essentially of DMS. 
     
     
         14 . The method of  claim 1  wherein the asphaltene solvent further comprises up to 25 mol % decant oil. 
     
     
         15 . The method of  claim 1  wherein the asphaltene deposit is an asphaltene accretion on a portion of the formation or is a sludge. 
     
     
         16 . A system for remediating asphaltene deposition in an oil-bearing formation containing asphaltene deposits, comprising:
 an asphaltene solvent comprising at least 75 mol % dimethyl sulfide (DMS);   an asphaltene solvent storage facility containing at least a portion of the asphaltene solvent;   a well extending into the oil-bearing formation positioned to introduce the asphaltene solvent into the formation to contact an asphaltene deposit therein, the well being structured and arranged to introduce the asphaltene solvent into the oil-bearing formation to contact the asphaltene deposit therein, wherein the asphaltene solvent storage facility is operatively fluidly coupled to the first well to provide the asphaltene solvent to the first well.   
     
     
         17 . The system of  claim 16  wherein the well is further structured and arranged to produce oil from the formation. 
     
     
         18 . The system of  claim 17  wherein the well is further structured and arranged to produce the asphaltene solvent from the formation. 
     
     
         19 . The system of  claim 16  wherein the well is a first well and further comprising a second well extending into the formation positioned to produce oil from the formation, wherein the second well is structured and arranged to produce oil from the formation. 
     
     
         20 . The system of  claim 16  wherein the asphaltene solvent further comprises up to 25 mol % decant oil. 
     
     
         21 . The system of  claim 16  wherein the asphaltene solvent consists essentially of DMS. 
     
     
         22 . The system of  claim 16  wherein the asphaltene solvent is first contact miscible with oil in or from the formation.