Fluid separation system for hydrocarbon wells

Abstract

A surface-adjustable downhole exhaust valve for use with a relatively slowly producing oil well to exhaust heavier water below a production zone while producing essentially oil at the surface.

What is claimed is: 
     
         1 . A heavy fluid exhaust system for an oil well, comprising:
 production tubing extending from a production zone up to a surface, having a pump for lifting formation fluid through the production tubing to the surface; and   a surface-adjustable downhole exhaust valve in communication with the production tubing structured to exhaust downhole fluid under head pressure from the production tubing, with a rate of exhaust adjustable from the surface.   
     
     
         2 . The system of  claim 1  wherein the production tubing includes a secondary exhaust chamber portion in fluid communication with a lower portion of the production tubing and with the exhaust valve. 
     
     
         3 . The system of  claim 1  wherein the exhaust valve is structured such that the rate of exhaust is mechanically adjustable from the surface. 
     
     
         4 . The system of  claim 1  wherein the pump includes a sucker rod and a portion of the exhaust valve is structured to be in contact with the sucker rod. 
     
     
         5 . The system of  claim 4  wherein a rotation of the sucker rod adjusts a bias of the exhaust valve. 
     
     
         6 . The system of  claim 1  wherein the valve exhausts a heavier fluid into a region of lesser pressure than the production zone and the pump lifts a lighter fluid to the surface. 
     
     
         7 . The system of  claim 6  wherein the heavier fluid is predominantly water and the lighter fluid is predominantly oil. 
     
     
         8 . The system of  claim 1  wherein the valve is spring biased. 
     
     
         9 . The system of  claim 1  wherein the valve is structured to exhaust fluid into a region below a bottomhole packer in the well. 
     
     
         10 . A method for producing lighter fluid from a well, comprising:
 drawing in and lifting formation fluid in production tubing, the formation fluid extending in a well from a downhole production zone to a surface, and wherein heavier fluid settles and lighter fluid rises in the production tubing;   exhausting heavier settled fluid from the production tubing, under pressure from the fluid in the production tubing, into a lower pressure region outside of the production zone, regulated by a surface-adjustable exhaust valve sensitive to weight of fluid in the production tubing; and   adjusting at the surface the sensitivity of the valve to the weight of the fluid in the production tubing such that predominantly lighter formation fluid is lifted to the surface and predominantly heavier formation fluid is exhausted outside the zone.   
     
     
         11 . The method of  claim 10  wherein the formation fluid includes oil and water and wherein the lighter formation fluid is predominantly oil and the heavier formation fluid is predominantly water. 
     
     
         12 . The method of  claim 10  wherein adjusting the sensitivity of the valve to the weight includes initially adjusting to a high target weight, relatively, and gradually adjusting the sensitivity of the valve to lower target weights until lighter fluid is predominantly lifted to the surface. 
     
     
         13 . The method of  claim 10  wherein the adjusting includes rotating a sucker rod associated with a downhole pump. 
     
     
         14 . The method of  claim 10  that includes adjusting the rate of the drawing in and lifting such that a heavier fluid is exhausted through the exhaust valve. 
     
     
         15 . The system of  claim 1  wherein the pump is a jack pump, wherein the formation fluid lifted to the surface is primarily oil, wherein the downhole fluid exhausted is primarily water, and wherein the exhaust valve is connected to and located below the jack pump in a bottom portion of the well.