Well jet device

Abstract

The invention relates to pumping equipment. The inventive jet device comprises a packer, a pipe column and a cradle in which drain ports are embodied and on which a jet pump is mounted in a body. Said body is provided with a channel for supplying an active medium to the nozzle, a channel for supplying a pumped-out medium, and a channel for evacuating the mixture of said mediums. The body also comprises a through channel embodied therein above the channel for supplying a pumped-out medium, connected thereto and used for arranging a sealing unit. Said sealing unit comprises a channel for passing the pumped out medium of a cable and a channel for supplying the pumped out medium of the cable used for arranging instruments and equipment. The channel for supplying a pumped-out the active medium is connected to the drain ports and to the space around the pipe column by means of said ports. The channel for evacuating the mixture the mediums from the jet pump is connected to the internal space of tubes above the jet pump. The sealing unit is embodied in such a way that it makes it possible to arrange thereinside a mechanism for bringing in the well and extracting therefrom the body containing the jet pump. A threaded hole for connecting autonomous measuring instruments to the body is embodied in the lower part thereof.

Description

FIELD OF INVENTION

[0001] This invention relates to the field of pumping engineering, mainly to downhole jet units for oil production.

PRIOR ART

[0002] Known in the art is a downhole jet unit comprising a jet pump installed on the production string in the well and a geophysical instrument placed in the production string below the said jet pump (RU 2059891 C1).

[0003] The said jet pumping unit enables to pump different extracted media, e.g., oil, out of the well with the simultaneous treatment of the extracted medium and the well formation zone, but the said unit provides for supply of a working medium to the nozzle of the jet unit along the string, which in some cases narrows the field of application of the said unit.

[0004] The closest, as to its technical essence and the achievable result, to this invention is a downhole jet unit comprising a packer, a piping string having a support wherein drain ports are made and onto which a jet pump with its housing is installed, the said housing of the said pump comprising a passage for supplying an active medium to the nozzle of the jet pump, a passage for supplying the medium, as pumped out of the well, to the jet pump and a passage for removing a medium mixture from the jet pump, and in the housing, above the passage for supplying a pumped out medium, a through passage in communication with the latter being made with a mounting face for installing a sealing assembly, and the sealing assembly comprises a through passage with the possibility of leading, through the latter and the said passage for supplying the pumped out medium, a cable for the purpose of installing, in the well below the jet pump, instruments and equipment with the possibility of moving them along the well bore when the jet pump is or is not operated (RU 2143597 C1).

[0005] The said downhole jet unit enables to perform various production operations in the well below the jet pump installation level by, inter alia, reducing a pressure difference both above and below the sealing assembly. However, the said downhole jet unit does not enable to utilize its possibilities in full due to non-optimal relationships between dimensions of various components of the construction of the downhole jet unit and due to such arrangement of the jet pump in its housing that is non-optimal for a number of applications.

DISCLOSURE OF INVENTION

[0006] The objective of this invention is to optimize the arrangement and the dimensions of various components of the construction of the well jet unit and, owing to it, to raise the reliability of operation of the well jet unit.

[0007] The stated objective is achieved owing to the fact that the well jet unit comprises a packer, a piping string having a support wherein drain ports are made and onto which a jet pump with its housing is installed, the said housing of the said pump comprising a passage for supplying an active medium to the nozzle of the jet pump, a passage for supplying the medium, as pumped out of the well, to the jet pump and a passage for removing a media mixture from the jet pump, and in the housing, above the passage for supplying a pumped out medium, a through passage in communication with the latter being made with a mounting face for installing a sealing assembly, and the sealing assembly comprises a through passage with the possibility of leading, through the latter and the said passage for supplying the pumped out medium, a cable for the purpose of installing, in the well below the jet pump, instruments and equipment with the possibility of moving them along the well bore when the jet pump is or is not operated, wherein, according to this invention, the passage for supplying the active medium to the nozzle of the jet pump communicates with the drain ports and through the latter with the space surrounding the piping string, the passage for removing a media mixture from the jet pump communicates with the inner cavity of the piping string above the jet pump, the through passage is made with the possibility of installing in it, with the closure of the through passage, a device for delivering into and removing from the well the housing with the jet pump, and in the bottom part of the housing of the jet pump a threaded hole is made for attaching autonomous measuring equipment to the housing, wherein the outer diameter (D) of the jet pump housing is at least 1.0 mm less that the least inner diameter (D1) of the piping string, the diameter (D2) of the axial passage in the sealing assembly is at least 0.01 mm higher than the diameter (D3) of the cable, and the diameter (D4) of the passage for supplying the pumped out medium is at least 2 mm higher than the diameter D3 of the cable, and sealing rings and a retaining mechanism are installed on the housing of the jet pump.

[0008] The analysis of the operation of the well jet unit has shown that the its reliability may be increased through more optimal arrangement of the construction components in the jet unit housing and making them according to strictly defined dimensions. It has been found out, in particular, that the diameter of the passage for supplying the pumped out medium may not be taken arbitrarily. It is due to the fact that a too large diameter of the passages results in a reduction in the strength of the unit, but a too small diameter of those passages results in lowering the capacity of the jet pump. It has been found out in this connection that the making of the diameter of the passage for supplying the pumped out medium at least 2 mm higher than the diameter of the cable enables to pass to the jet pump the greatest amount of the medium pumped out of the well, which corresponds to the maximum capacity of the jet pump, with the minimal hydraulic losses. As to the upper limit, it should be defined by the strength characteristics of the jet pump construction, and, first of all, by those of the jet pump housing. In each particular case this value is to be determined individually. In the course of the unit operation studies of different well modes are conducted. It is necessary to install and remove the housing with the jet pump in the piping string. It has been determined that it is advisable to make the diameter of the jet pump housing at least 1.0 mm less than the inner diameter of the piping string, and sealing rings and a mechanism which retains the jet pump housing in its position relative to the support in the well. In the result, possible sticking of the housing in the piping string is precluded and the overflowing of the medium from the space above the housing to the under-packer space in the well is ensured. It has already been said that in the process of the unit operation it is necessary to move instruments and equipment installed on the cable along the well and, at the same time, minimize the medium flow through the axial passage of the sealing assembly. It has been achieved by making the diameter of the axial passage in the sealing assembly at least 0.01 mm greater than the diameter of the cable, onto which the instruments and equipment are installed. The making of a threaded hole in the bottom part of the jet pump enables to install various measuring devices operating autonomously, and, owing to this, expand the range of studies conducted in the well.

[0009] Thus, the objective of the invention—to optimize the arrangement and the dimensions of the construction components of the unit and, owing to it, raise the reliability of operation of the downhole jet unit—has been achieved.

BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 represents a longitudinal section of the disclosed well jet unit.

[0011] FIG. 2 represents a longitudinal section of the well jet unit with the device for delivering into and removing from the well the housing with the jet pump, which is installed instead of the sealing assembly.

PREFERRED EMBODIMENT OF THE INVENTION

[0012] The proposed well jet unit comprises a packer 1, a piping string 2, having a support 3 wherein drain ports 4 are made and onto which a jet pump 6 with its housing 5 is installed, the said housing 5 comprises: a passage 7 in communication with drain ports 4 for supplying an active medium to the nozzle 8 of the jet pump 6 from the space surrounding the piping string 2, a passage 9 for supplying the medium pumped out of the well to the jet pump 6 and a passage 10 for removing a medium mixture from the jet pump 6 into the inner cavity of the piping string 2 above the jet pump 6, and in the housing 5 above the passage 9 for supplying the pumped out medium a through passage 11, being in communication with the passage 9 and being made with a mounting face 12 for installing a sealing assembly 13, and the sealing assembly 13 comprises a through passage 14 with the possibility of leading, through it and the passage 9 for supplying the pumped out medium, a cable 15 for the purpose of installing on it, in the well below the jet pump 6, instruments and equipment with the possibility of moving them along the well bore when the jet pump 6 is or is not operated. The through passage 11 is made with the possibility of installing in it, with the closure of the through passage 11, a device 17 for delivering into and removing from the well the housing 5 with the jet pump 6, and in the bottom part of the housing 5 of the jet pump 6 a threaded hole 18 is made for the purpose of connecting with the housing 5 of the autonomous measuring equipment 21, wherein the outer diameter (D) of the housing 5 of the jet pump 6 being at least 1.0 mm less than the least inner diameter (D1) of the piping string 2, the diameter (D2) of the axial passage 14 in the sealing assembly 13 is at least 0.01 mm greater than the diameter (D3) of the cable 15, and the diameter (D4) of the passage 9 for supplying the pumped out medium being at least 2 mm greater than the diameter (D3) of the cable 15, the sealing rings 19 and the retaining mechanism 20 being installed onto the housing 5 of the jet pump 6.

[0013] The piping string 2 with the packer 1 and the support 3 are lowered into the well, and the packer being installed above the producing formation. Then the packer 1 is put into the operating position where it divides the well space surrounding the piping string 2. Then the housing 5 with the jet pump 6 and the sealing assembly 13 as well as the instruments and equipment arranged on the cable 15 below the housing 6 are lowered into the well. The housing 5 with the jet pump 6 are fixed in the support 3 by using the retaining mechanism 20. The working medium, e.g., water, salt solution, oil, etc., is pumped into the hole clearance surrounding the piping string 2. From the hole clearance the working medium flows through the ports 4 and the passage 7 into the active nozzle 8 of the jet pump 6. Within several seconds after the pumping of the working medium through the active nozzle 8 a stable jet is formed at its outlet, which, flowing out of the nozzle 8, entrains the medium surrounding it into the jet pump 6, which results in a pressure reduction, first, in the passage 9 for supplying the pumped out medium and then in the under-packer space in the well, thus creating a pressure drawdown onto the producing formation. The pressure reduction value depends on the speed at which the working medium comes through the active nozzle 8, such speed depending, in its turn, on the pressure at which the pumped out medium is discharged into the hole clearance above the packer 1. In the result the formation medium comes along the piping string 2 and through the passage 9 into the jet pump 6 where it is mixed with the working medium, and the mixture of the media flows by the energy of the working medium along the piping string 2 from the well on the surface. During pumping out the formation medium with the use of the equipment and instruments 16 installed on the cable 15 the parameters of the pumped out formation medium are monitored, and the producing formation is influenced by physical fields. According to a set task it is possible to move the instruments and equipment 16 along the well. If the installation of the instruments and equipment 16 on the cable 15 below the housing 5 of the jet pump 6 is not necessary, the device 17 is installed in the through passage 11 instead of the sealing assembly 13, and the device 17 is used for installing into and removing from the piping string 2 the housing 5 with the jet pump 6 and the autonomous measuring equipment 21, if the latter has been installed on the housing 5.

Industrial Applicability

[0014] This invention may be applied in testing, developing and operating oil and gas condensate wells as well as during workover jobs on them.

Claims

1. A well jet unit which comprises a packer, a piping string having a support wherein drain ports are made and onto which a jet pump in its housing is installed, the said housing of the said pump comprising: a passage for supplying an active medium to the nozzle of the jet pump, a passage for supplying the medium pumped out of the well to the jet pump, and a passage for removing a media mixture from the jet pump, and in the housing, above the passage for supplying a pumped out medium, a through passage in communication with the latter being made with a mounting face for installing a sealing assembly, and the sealing assembly comprises a through passage with the possibility of leading through it and the said passage for supplying the pumped out medium a cable for the purpose of installing, in the well below the jet pump, instruments and equipment with the possibility of moving them along the well bore when the jet pump is or is not operated, characterized in that, according to this invention, the passage for supplying the active medium to the nozzle of the jet pump communicates with the drain ports and, through the latter, with the space surrounding the piping string, the passage for removing a media mixture from the jet pump communicates with the inner cavity of the piping string above the jet pump, the through passage is made with the possibility of installing in it, with the closure of the through passage, a device for delivering into and removing from the well the housing with the jet pump, and in the bottom part of the housing of the jet pump a threaded hole is made for attaching autonomous measuring equipment to the housing, wherein the outer diameter (D) of the jet pump housing is at least 1.0 mm less that the least inner diameter (D1) of the piping string, the diameter (D2) of the axial passage in the sealing assembly is at least 0.01 mm greater than the diameter (D3) of the cable, and the diameter (D4) of the passage for supplying the pumped out medium is at least 2 mm greater than the diameter D3 of the cable, and sealing rings and a retaining mechanism being installed on the housing of the jet pump.