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

[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 co...

AI Technical Summary

Benefits of technology

[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.

[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.

Problems solved by technology

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.

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