Device and method for pressure regulation of a well

Abstract

A device for the pressure regulation of a well is provided with a return pump for drilling fluid. The operating level of drilling fluid in an annulus which is fanned between an outer pipe and an inner pipe is at a height level between the upper portion of the outer pipe and the bottom portion of the well. The return pump is in the annulus.

1 . A device for the pressure regulation of a well comprising a return pump for drilling fluid, operating level of drilling fluid in an annulus which is formed between an outer pipe and an inner pipe is at a height level between an upper portion of the outer pipe and a bottom portion of the well, wherein the annulus axially open past the return pump, wherein the return pump is positioned in the annulus and wherein a return pipe extends through the annulus from the return pump and out of the well. 
     
     
         2 . The device in accordance with  claim 1 , wherein the inlet of the return pump is placed at a lower level than a lowest expected operating level of the drilling fluid. 
     
     
         3 . The device in accordance with  claim 1 , wherein at least in an area of the annulus within which an expected operating level of returning drilling fluid is the annulus provided with a restriction lining elongated, in the longitudinal direction of the outer pipe. 
     
     
         4 . The device in accordance with  claim 3 , wherein, in the main, the restriction lining surrounds the inner pipe. 
     
     
         5 . The device in accordance with  claim 3 , wherein in its operating position, the restriction lining is axially fixed relative to the outer pipe. 
     
     
         6 . The device in accordance with  claim 3 , wherein the restriction lining comprises several lining portions. 
     
     
         7 . The device in accordance with  claim 3 , wherein the return pump is in the restriction lining. 
     
     
         8 . The device in accordance with  claim 3 , wherein the restriction lining is provided with a fill pipe. 
     
     
         9 . A method of pressure-regulating a well which is provided with a return pump for drilling fluid and in which the operating level of drilling fluid in an annulus which is formed between an outer pipe and an inner pipe is at a height level between the upper end portion of the outer pipe and the bottom portion of the well, and where the annulus is axially open past the return pump comprising:
 placing the return pump in the annulus; and   connecting a return pipe to the return pump where the return pipe extends through the annulus and out of the well.   
     
     
         10 . The method in accordance with  claim 9 , wherein the method further comprises placing the inlet of the return pump at a height level lower than the lowest expected operating level of the drilling fluid. 
     
     
         11 . The method in accordance with  claim 9 , wherein the method further comprises placing an elongated restriction lining at least in an area of the annulus within which the expected operating level of returning drilling fluid is. 
     
     
         12 . The method in accordance with  claim 11 , wherein the method further comprises regulating the capacity of the return pump regulate the operating level to the desired height level along the restriction lining.