Artificial lift system for hydrocarbon wells using oleophilic materials

Abstract

A spool assembly alternately lowers an oleophilic absorbent material into a hydrocarbon-bearing fluid column in a wellbore and winds the material onto the spool, releasing the hydrocarbon-bearing fluid into a tank at the surface.

It is claimed: 
     
         1 . A method for producing hydrocarbons to the surface from a subterranean wellbore extending through a production zone, the method comprising:
 repeatedly:
 lowering an absorbent assembly having at least one oleophilic absorbent material into a fluid column in the wellbore; 
 absorbing hydrocarbon-bearing fluid from the fluid column with the absorbent assembly; 
 raising the absorbent assembly to the surface; 
 winding the absorbent assembly on a spool at the surface; and 
 removing the hydrocarbon-bearing fluid from the absorbent assembly at the surface. 
   
     
     
         2 . The method of  claim 1 , wherein removing the hydrocarbon-bearing fluid further comprises compressing the absorbent assembly. 
     
     
         3 . The method of  claim 1 , wherein removing the hydrocarbon-bearing fluid further comprises applying centrifugal force to the absorbent assembly. 
     
     
         4 . The method of  claim 1 , wherein removing the hydrocarbon-bearing fluid further comprises wrapping the absorbent assembly around a spool. 
     
     
         5 . The method of  claim 1 , wherein the at least one oleophilic absorbent material is taken from the group consisting of: polypropylene, poly-blend materials, acrylic, nylon, polyester, treated cotton fiber or flakes, flax fiber, ground corn-cob, paper mill waste, wool, sponge, para-aramids, high modulus polyethylene fiber, polypropylene and polyester textured filaments, and chamois. 
     
     
         6 . The method of  claim 1 , wherein the absorbent assembly further comprises at least one hydrophilic material. 
     
     
         7 . The method of  claim 1 , wherein the absorbent assembly further comprises an absorbent material housed in a permeable container. 
     
     
         8 . The method of  claim 1 , further comprising: automatically, using a controller, maintaining the absorbent assembly into the fluid column in the wellbore at a selected depth for a selected period of time. 
     
     
         9 . The method of  claim 1 , wherein repeatedly lowering the absorbent assembly into the fluid column further comprises: automatically, using a controller, lowering the absorbent assembly into the fluid column at sequentially lower depths on sequential trips into the fluid column. 
     
     
         10 . The method of  claim 1 , wherein the fluid column in the wellbore comprises a hydrocarbon-bearing fluid layer above a water-bearing fluid layer; and further comprising: lowering the absorbent assembly into the water-bearing layer of the fluid column. 
     
     
         11 . An apparatus for producing hydrocarbons to the surface from a subterranean wellbore extending through a production zone, a fluid column having a hydrocarbon-bearing fluid above a water-bearing fluid in the wellbore, the apparatus comprising:
 a spool positioned in a tank, the tank having an outlet for selectively discharging fluid from the tank;   an absorbent assembly operable to be alternately wound on the spool and lowered into a fluid column in the wellbore, the absorbent assembly comprising at least one oleophilic absorbent material for absorbing the hydrocarbon-bearing fluid;   a motor operable to selectively rotate the spool in opposite directions, thereby lowering the absorbent assembly into the fluid column and winding the absorbent assembly on the spool;   the motor operable and spool operable to remove hydrocarbon-bearing fluid from the absorbent assembly by applying compression or centrifugal force to the absorbent assembly; and   a controller for automatically controlling operation of the motor to repeatedly lower and raise the absorbent assembly by operation of the motor and spool.   
     
     
         12 . The apparatus of  claim 11 , wherein removing the hydrocarbon-bearing fluid further comprises compressing the absorbent assembly. 
     
     
         13 . The apparatus of  claim 11 , wherein the at least one oleophilic absorbent material is taken from the group consisting of: polypropylene, poly-blend materials, acrylic, nylon, polyester, treated cotton fiber or flakes, flax fiber, ground corn-cob, paper mill waste, wool, sponge, para-aramids, high modulus polyethylene fiber, polypropylene and polyester textured filaments, and chamois. 
     
     
         14 . The apparatus of  claim 11 , wherein the absorbent assembly further comprises at least one hydrophilic material. 
     
     
         15 . The apparatus of  claim 11 , wherein the absorbent assembly further comprises a permeable container, and wherein the oleophilic absorbent material is housed in the permeable container. 
     
     
         16 . The apparatus of  claim 1 , wherein the controller is operable to automatically maintain the absorbent assembly in the fluid column at a selected depth for a selected period of time. 
     
     
         17 . The apparatus of  claim 1 , wherein the controller is operable to automatically lower the absorbent assembly into the fluid column at sequentially lower depths on sequential trips into the fluid column.