Device for hydraulically protecting a submersible electric motor of a downhole, preferably centrifugal, pump (variants)

Abstract

The invention can be used in installations for extracting downhole fluid. The device is in the form of a protector which is arranged between an electric motor and a downhole pump and comprises at least one stage, which comprises a cylindrical body, a tube surrounding the drive shaft of the pump, nipples, a damping bushing, an annular piston in a chamber formed in the space between the body and the tube and dividing the chamber into two sections, which are filled with dielectric fluid and formation fluid, and a formation fluid and dielectric fluid divider which is mounted freely in the chamber at the end of the piston which is in contact with the formation fluid. The divider can move autonomously and is in the form of a single component consisting of two pipe lengths of annular elements which are arranged one in the other and are rigidly interconnected by means of a common base, which is mounted so as to adjoin the ends of the two lengths on the annular-piston side. The annular piston and the divider are mounted in an annular chamber so as to adjoin the internal surface of the cylindrical body and the external surface of the tube with a clearance. The clearance space is filled with a protective medium having hydrophilic properties. The efficiency and operating reliability of the device are increased.

1 - 30 . (canceled) 
     
     
         31 . A device for hydraulically protecting a submersible electric motor of a downhole, comprising:
 a shaft;   a thrust bearing;   a radial bearing and at least one stage, which includes a cylindrical housing;   a tube surrounding the shaft, the tube being mounted coaxially inside the cylindrical housing so as to form an annular chamber between the cylindrical housing and the tube;   first and the second nipples;   at least one damping bushing;   at least one shaft seal; and   an annular piston and two protective elements capable of reciprocal movement in the annular chamber, which are mounted at an end of the annular piston, which is in contact with reservoir fluid, in the form of segments of outer and inner tubes;   wherein the annular piston divides the annular chamber into two sections, wherein one section is oriented towards the second nipple, connected with an annulus and filled with the reservoir fluid, and the other is oriented towards the first nipple, filled with dielectric fluid of the motor and has at least one centering carrier ring, at least one seal in a point of contact of the annular piston with an inner surface of the cylindrical housing, and at least one seal in a point of contact of the annular piston with an outer surface of the tube;   wherein a space between the outer surface of the annular piston and the inner surface of the cylindrical housing is filled with a protective medium;   wherein the segments of the inner and the outer tubes of the annular elements are located at the end of the annular piston oriented towards the second nipple and adjoining, respectively, an inner surface of the cylindrical housing and an outer surface of the tube with a gap between the same and respective adjoining surfaces, filled with a protective medium;   wherein a port of the second nipple connecting the section of the annular chamber filled with the reservoir fluid with the annulus has a reservoir fluid filter;   wherein the points, where the segments of the inner and the outer tubes adjoin the inner surface of the cylindrical housing and the outer surface of the tube, respectively, have gaps against the respective adjoining surfaces, are located near ends of the tube segments oriented towards the second nipple and being the farthest to the annular piston, and have seals;   wherein the shaft between the section of the annular chamber filled with the dielectric fluid and the end seal can be provided with a pumping device, which is connected via the port of the first nipple with a dielectric fluid filter with the section filled with the dielectric fluid;   wherein the segments of the inner and the outer tubes of the annular elements are rigidly interconnected by means of a solid common bottom at the end of the annular piston oriented towards the second nipple, where this side adjoins the ends of both tube segments of the annular elements so as to form a single piece freely accommodated in the annular chamber and capable of autonomous reciprocal movement independent of the annular piston and performing the function of a separator of the reservoir fluid and the dielectric fluid of the motor in the annular chamber;   wherein the protective medium includes hydro-oleophobic properties.   
     
     
         32 . The device according to  claim 31 , wherein the annular cavity inside the single piece of two annular elements rigidly interconnected by an annular bottom between the walls of the inner and the outer tube segments is open at the end of the cavity oriented towards the second nipple, and filled with a protective medium. 
     
     
         33 . The device according to  claim 31 , wherein the annular cavity inside the single piece of two annular elements rigidly interconnected by an annular bottom between the walls of the inner and the outer tube segments is closed at the end of the cavity oriented towards the second nipple, and filled with a protective medium. 
     
     
         34 . The device according to  claim 31 , further comprising additional points, where segments of the inner and the outer tubes of the annular elements adjoin the inner surface of the cylindrical housing and the outer surface of the tube, respectively, with a gap against the corresponding adjoining surfaces located along the length of these tube segments and provided with seals. 
     
     
         35 . The device according to  claim 31 , wherein the outer surface of the outer tube segment and the inner surface of the inner tube segment of the annular elements are provided with protrusions arranged in the gap between the respective surfaces of the two annular elements adjoining the inner surface of the cylindrical housing and the outer surface of the tube, and seals for the adjoining points of the tube segments of the two annular elements are located at the outer surface of each of these protrusions, where these protrusions are made near the ends of outer and the inner tube segments oriented towards the second nipple. 
     
     
         36 . The device according to  claim 31 , wherein the outer surface of the outer tube segment and the inner surface of the inner tube segment of the annular elements are provided with protrusions arranged in the gap between the respective surfaces of the annular elements adjoining the inner surface of the cylindrical housing and the outer surface of the tube, and seals for the adjoining points of the tube segments of the two annular elements are located at the outer surface of each of these protrusions, where these protrusions are distributed along the length of these tube segments. 
     
     
         37 . The device according to  claim 31 , further comprising:
 at least one additional single piece of two additional annular elements in the form of segments of the inner and the outer tubes rigidly interconnected by a common solid annular bottom located on the side of the adjacent single piece of the two rigidly interconnected annular elements, which piece is nearest to the annular piston and where the bottom is adjoining the ends of the two tube segments of the additional annular elements;   wherein the additional single piece is freely located in the annular chamber and capable of autonomous reciprocal movement independent of the annular piston and performing the function of a separator of the reservoir fluid and the dielectric fluid of the motor in the annular chamber;   wherein both of its additional annular elements are mounted in the annular chamber adjoining with a gap the internal surface of the cylindrical housing and the outer surface of the tube, respectively;   wherein points, where the inner and the outer tubes of the additional annular elements adjoin the inner surface of the cylindrical housing and the outer surface of the tube, respectively, have a gap between the same and the respective adjoining surfaces near the ends of the tube segments of the additional annular elements oriented towards the second nipple and being the farthest to the annular piston, and have seals, where the annular cavity of the additional single piece between the walls of the inner and the outer tube segments of each additional annular element is filled with a protective medium, and the space between adjacent pieces of two rigidly interconnected annular elements is filled with a separation fluid.   
     
     
         38 . The device according to  claim 31 , further comprising additional points, where segments of the inner and the outer tubes of the additional annular elements adjoin the inner surface of the cylindrical housing and the outer surface of the tube, respectively, with a gap against the corresponding adjoining surfaces located along the length of these tube segments of the additional annular elements and provided with seals. 
     
     
         39 . The device according to  claim 31 , wherein the outer surface of the outer tube segment and the inner surface of the inner tube segment of the additional annular elements are provided with protrusions arranged in the gap between the respective surfaces of the additional annular elements adjoining the inner surface of the cylindrical housing and the outer surface of the tube, and seals for the adjoining points of the annular elements are located at the outer surface of each of these protrusions, where these protrusions are made near the ends of outer and the inner tube segments oriented towards the second nipple. 
     
     
         40 . The device according to  claim 31 , wherein the outer surface of the outer tube segment and the inner surface of the inner tube segment of the additional annular elements are provided with protrusions arranged in the gap between the respective surfaces of the additional annular elements adjoining the inner surface of the cylindrical housing and the outer surface of the tube, and seals for the adjoining points of the additional annular elements are located at the outer surface of each of these protrusions, where these protrusions are distributed along the length of these tube segments of the additional annular elements. 
     
     
         41 . The device according to  claim 31 , wherein the protective medium of the annular chamber in the area of movement of the single piece of two additional annular elements between the end of the said annular chamber on the side of the second nipple and the end of the annular piston oriented towards the second nipple is a dielectric buffer fluid, preferably based on silicone compounds. 
     
     
         42 . The device according to  claim 31 , wherein the space of the annular chamber between the location area of the dielectric barrier fluid and the area of the annular chamber near the second nipple is filled with a barrier fluid, preferably based on polyethylene oxides. 
     
     
         43 . The device according to  claim 31 , wherein the dielectric buffer fluid and the dielectric barrier fluid are immiscible with each other, and the density of the dielectric barrier fluid is at least equal to the density of the buffer fluid. 
     
     
         44 . The device according to  claim 31 , wherein the separation fluid between the adjacent annular elements is a dielectric buffer fluid. 
     
     
         45 . The device according to  claim 31 , wherein the tube segments of the annular elements have various forms of generating lines.