Downhole Compressor

Abstract

A downhole compressor includes: a casing disposed inside a gas well; a rotor built inside the casing; and an impeller disposed at the rotor, and an electromagnetic control unit that electromagnetically controls a relative position of the rotor inside the casing is provided.

What is claimed is: 
     
         1 . A downhole compressor, comprising:
 a casing disposed inside a well;   a rotor built inside the casing; and   an impeller disposed at the rotor,   wherein an electromagnetic control unit configured to electromagnetically control a relative position of the rotor inside the casing is provided.   
     
     
         2 . The downhole compressor according to  claim 1 , wherein a bearingless motor is provided as the electromagnetic control unit. 
     
     
         3 . The downhole compressor according to  claim 1 , wherein a magnetic bearing is provided as the electromagnetic control unit. 
     
     
         4 . The downhole compressor according to  claim 1 , wherein
 a pressure regulating chamber is provided at a back surface portion of the impeller,   a shaft sealing device is provided between an outlet portion of the impeller and the pressure regulating chamber, and   a communication unit is provided between the pressure regulating chamber and an inlet portion of the impeller.   
     
     
         5 . The downhole compressor according to  claim 4 , wherein
 a displacement meter configured to measure axial displacement is provided, and   the displacement meter is disposed at a back surface portion of the impeller.   
     
     
         6 . The downhole compressor according to  claim 4 , wherein a leakage amount at the shaft sealing device is reduced when the rotor is displaced to an axial upstream side. 
     
     
         7 . The downhole compressor according to  claim 6 , wherein the shaft sealing device includes axial clearance, and the axial clearance is reduced when the rotor is displaced to the axial upstream side. 
     
     
         8 . The downhole compressor according to  claim 1 , wherein a control device for the electromagnetic control unit is disposed on the ground. 
     
     
         9 . The downhole compressor according to  claim 8 , wherein an operating condition is determined by using a control signal of the electromagnetic control unit.