Use of natural gas for deliquification

Abstract

A method for producing hydrocarbons from a well that includes a borehole, production tubing in the borehole, and an annulus between the production tubing and the borehole, the borehole containing an undesirable amount of liquid, comprises the steps of: a) providing a source of liquefied natural gas (LNG), b) regasifying the LNG, c) pressurizing the regasified LNG to a pressure above the pressure in the annulus, d) injecting the pressurized regasified LNG into the annulus, e) allowing the pressurized regasified LNG to flow into and up through the production tubing; thereby reducing the amount of liquid in the borehole, f) recovering the pressurized regasified LNG along with produced gas and transmitting both.

What is claimed is: 
     
         1 . A method for producing hydrocarbons from a well that includes a borehole, production tubing in the borehole, and an annulus between the production tubing and the borehole, the borehole containing an undesirable amount of liquid, the method comprising the steps of:
 a) providing a source of liquefied natural gas (LNG);   b) regasifying the LNG;   c) pressurizing the regasified LNG to a pressure above the pressure in the annulus;   d) injecting the pressurized regasified LNG into the annulus;   e) allowing the pressurized regasified LNG to flow into and up through the production tubing; thereby reducing the amount of liquid in the borehole; and   f) recovering the pressurized regasified LNG along with produced gas and transmitting both.   
     
     
         2 . The method of  claim 1  wherein the LNG comprises at least 95% methane. 
     
     
         3 . The method of  claim 1  wherein the LNG comprises at least 98% methane. 
     
     
         4 . The method of  claim 1  wherein step b) comprises passing the LNG through a vaporizer to produce a regasified LNG stream. 
     
     
         5 . The method of  claim 1  wherein step c) comprises passing the regasified LNG stream through a compressor to produce a pressurized regasified LNG stream. 
     
     
         6 . The method of  claim 1  wherein step f) is carried out without further separation of the recovered gases. 
     
     
         7 . The method of  claim 1 , further including the step of sensing when an undesired amount of liquid has accumulated in the borehole. 
     
     
         8 . The method of  claim 1  wherein step e) includes using a plunger to facilitate movement of liquid out of the borehole. 
     
     
         9 . The method of  claim 1  wherein step b) includes using heat from ambient air. 
     
     
         10 . The method of  claim 1  wherein step b) includes using electric heat or heat from combusting a fuel. 
     
     
         11 . An apparatus for producing hydrocarbons from a well that includes a borehole, production tubing in the borehole, and an annulus between the production tubing and the borehole, the borehole containing an undesirable amount of liquid, the apparatus comprising:
 a tank of liquefied natural gas (LNG);   a vaporizer for regasifying the LNG;   a compressor for pressurizing the regasified LNG to a pressure above the pressure in the annulus; and   a fluid connection for injecting the pressurized regasified LNG into the annulus.   
     
     
         12 . The apparatus of  claim 1  wherein the LNG comprises at least 95% methane. 
     
     
         13 . The apparatus of  claim 1  wherein the LNG comprises at least 98% methane. 
     
     
         14 . The apparatus of  claim 1 , further including a sensor adapted to sense when an undesired amount of liquid has accumulated in the borehole. 
     
     
         15 . The apparatus of  claim 1 , further including a plunger in the tubing for facilitating movement of liquid out of the borehole. 
     
     
         16 . The apparatus of  claim 1  wherein the vaporizer uses heat from ambient air. 
     
     
         17 . The apparatus of  claim 1  wherein the vaporizer uses electric heat or heat from combusting a fuel.