Liquid Lift Pumps for Gas Wells

Abstract

A wellbore liquid lift pump includes a pump chamber disposed in a wellbore at a selected longitudinal position and within a liquid column therein. The pump chamber has one way valves proximate each longitudinal end thereof. One of the one way valves is in fluid communication with the liquid column. The other one way valve is in fluid communication with a conduit extending from the pump chamber to the surface. The pump includes means for displacing a volume of the pump chamber by application of pressure thereto. The pressure provided by at least one of a gas and a liquid having a density lower than liquid within the liquid column.

What is claimed is: 
     
         1 . A wellbore liquid lift pump, comprising:
 a pump chamber disposed in a wellbore at a selected longitudinal position and within a liquid column therein, the pump chamber having one way valves proximate each longitudinal end thereof, one of the one way valves in fluid communication with the liquid column, the other one way valve in fluid communication with a conduit extending from the pump chamber to the surface; and   means for displacing a volume of the pump chamber by application of pressure thereto, the pressure provided by at least one of a gas and a liquid having a density lower than liquid within the liquid column.   
     
     
         2 . The wellbore liquid lift pump of  claim 1  wherein the means for displacing comprises an inflatable bladder. 
     
     
         3 . The wellbore liquid lift pump of  claim 2  wherein the pressure is applied through a tube in fluid communication with an interior of the bladder, the tube extending to the surface. 
     
     
         4 . The wellbore liquid lift pump of  claim 1  wherein the means for displacing comprises a steam generator. 
     
     
         5 . The wellbore liquid lift pump of  claim 4  wherein the steam generator comprises a least one electrically operated heating element. 
     
     
         6 . A method for lifting liquid out of a wellbore drilled through subsurface formations, comprising:
 applying pressure to displace a volume of a chamber disposed in a liquid column in the wellbore, the displacing constrained to movement of liquid in the chamber in a direction toward the surface, the applying pressure comprising at least one of applying gas pressure and applying liquid pressure, wherein the liquid has a density less than water in the water column; and   releasing the pressure to enable water in the water column to enter the chamber.   
     
     
         7 . The method of  claim 6  wherein the applying pressure comprises pumping from the surface. 
     
     
         8 . The method of  claim 7  wherein the pressure is communicated to an interior of an inflatable bladder disposed in the chamber. 
     
     
         9 . The method of  claim 6  wherein the applying pressure comprises heating water in the chamber to cause boiling thereof. 
     
     
         10 . The method of  claim 8  wherein the releasing pressure comprises cooling the chamber.