RU2299970C1 - Packer assembly for selective reservoir testing - Google Patents

Abstract

FIELD: oil production, particularly devices to perform reservoir tests in wells, including that having opened bores.

SUBSTANCE: device comprises upper connection unit for device fixation on pipe string, upper and lower packers with sealing members, upper and lower movable rods provided with axial channels arranged inside packers and hollow filter installed between upper and lower packers. Axial channel of lower movable rod is provided with solid partition. Upper and lower movable rods are fixedly connected with each other in air-tight manner and provided with upper connection unit. Upper and lower rods may be displaced only in downward direction with respect to upper and lower packers. Sealing members of upper and lower packers are located between stops. Upper stop of lower packer is fixedly connected with lower stop of upper packer provided with balloon-type centrators through hollow filter. The balloon-type centrators are arranged from top thereof. One stop of each packer is made as hydraulic cylinder fixedly connected with packer and as annular piston cooperating with sealing member. Inner cavities of each hydraulic cylinder may cooperate with axial channels of movable rods over solid partition and may provide air-tight isolation thereof during movable rod displacement in downward direction with respect to packers. Upper movable rod is provided with radial channel sealed with packer and adapted to cooperate with ambient space through hollow filter during movable rods displacement in downward direction with respect to packers.

EFFECT: simplified structure, decreased costs of device production and increased operational reliability.

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Description

The invention relates to the oil industry, and in particular to devices for testing formations in vertical, directional and horizontal wells, including open-hole wells.

A well-known formation tester without reliance on the bottom hole of the IM-8 interval type developed by the VNIIBT Institute (Yasashin A.M. et al. Technique and technology for testing seams in the process of drilling deviated wells. M .: Nedra, 1972, p. 84-94), including upper and lower packers with hydraulic sealing elements, a filter (acting simultaneously as a housing in which hydraulic discharge channels of serial communication of sealing elements and equalization device are located), equalization channel, inlet valve, hydraulic a cylinder with a differential piston, a shut-off valve for controlling the packing (equipped with a spring lamp), a cam mechanism. When using IP-8 for packing, lifting and rotation of the pipe string is carried out. Also, by rotating the drill pipe, the inlet valve closes.

The disadvantages of the design of the device are:

firstly, the complexity of the design, due to the large number of nodes and parts;

secondly, the complexity of manufacturing, due to the fact that hydraulic (injection) channels are made in the filter body, connecting successively the cavities of the lower and upper packers;

thirdly, the complexity of the technology of using the device, due to the fact that during operation it is necessary to carry out axial movements and rotations of the pipe string to pack and control the operation of the deep valve system, which complicates the implementation of reliable packing.

The closest is a packer for selective formation testing (patent RU No. 2101463, IPC 7 ЕВВ 33/124; 49/08, published in Bulletin No. 1 of 01/10/1998), containing the upper and lower packers with hydraulic sealing elements , movable rods made with axial channels located in the cavities of the packers, and a hollow filter installed between the upper and lower packers, while in the axial channel of the movable rod of the upper packer there is a check valve made with a bypass channel, the movable rod of the lower packer is equipped with a blind overhang rodkoy and forms its upper part to the lower packer chamber connected to the bypass channel a check valve flexible connector disposed in the cavities of the filter.

The disadvantages of the design of the device are:

firstly, the complexity of the design, due to the large number of nodes and parts;

secondly, high material costs due to the complexity of manufacture, assembly, use and maintenance;

thirdly, low reliability due to the large number of mating parts.

The objective of the invention is to simplify the design of the device, reduce material costs for manufacturing, as well as increase reliability in operation.

The problem is solved by a packer for selective testing of formations containing an upper connecting unit for fixing on a pipe string, upper and lower packers with sealing elements, upper and lower movable rods made with axial channels placed in the cavities of the packers, and the axial channel of the lower movable rod equipped with a blank partition, and a hollow filter installed between the upper and lower packers.

What is new is that the upper and lower movable rods are rigidly and hermetically connected to each other, provided with a connecting node on top and are made to move relative to the upper and lower packers only downward, while the sealing elements of the upper and lower packers are located between the stops, with the upper stop of the lower the packer is rigidly connected by a hollow filter to the lower stop of the upper packer, which is equipped with spring centralizers from above, and one of the stops of each packer is made in the form of a hydraulic cylinder, rigidly connected with the packer, and an annular piston interacting with the sealing element, the internal cavities of each hydraulic cylinder being configured to interact with the axial channel of the movable rods above the blank partition and tight insulation when moving the movable rods down relative to the packers, while the upper movable rod is provided with a hermetically closed upper packer radial channel configured to interact with the outer space through the hollow filter when moving the movable rods out relatively packers.

The drawing in longitudinal section shows the proposed packer for selective testing of formations in the initial position.

A packer for selective formation testing comprises upper 1 and lower 2 packers with sealing elements 3 and 4, respectively, upper 5 and lower 6 movable rods made with axial channels 7 and 8, located respectively in the cavities of the upper 1 and lower 2 packers.

The axial channel 8 of the lower movable rod 6 is provided with a blank partition 9. Between the upper 1 and lower 2 packers, a hollow filter 10 is installed.

The upper 5 and lower 6 movable rods are rigidly and hermetically connected to each other by means of a pipe 11, and on top the upper movable rod 5 is equipped with an upper connecting unit 12. The upper 5 and lower 6 movable rods are only movable relative to the upper 1 and lower 2 packers.

The sealing elements 3 and 4 of the upper 1 and lower 2 packers, respectively, are located between the stops 13 (14) and 15 (16). The upper stop 15 of the lower packer 2 is rigidly connected by the hollow filter 12 to the lower stop 14 of the upper packer 1.

The upper packer 1 is provided with spring centralizers 17. The stop 13 of the upper packer 1 and the stop 16 of the lower packer 2 are made in the form of a hydraulic cylinder 18 (19) rigidly connected responsibly to the upper 1 and lower 2 packers, and an annular piston 20 (21) interacting with sealing element 3 (4).

The internal cavities 22 (23) of each hydraulic cylinder 18 (19) are made with the possibility of interaction with the axial channel 7 (8) of the movable rods 5 (6) above the blind partition 9 and airtight insulation when moving the movable rods 5 (6) down relative to the packers 1 (2 ) The upper movable rod 5 is provided with a hermetically sealed upper packer 1 radial channel 24, configured to interact with the outer space (not shown) through the hollow filter 10 when moving the movable rods 5 (6) down relative to the packers 1 (2).

Unauthorized fluid flows are excluded by sealing elements 25, 26, 27, 28.

Packing device for selective testing of formations works as follows.

At the wellhead (not shown), the required length of the filter 10 is selected depending on the height of the test formation and, using an adapter 11, the upper 5 and lower 6 movable rods are connected. After that, the packer assembly on the pipe string 29 is lowered into the well, while the axial channel 7 (8) of the movable rod 5 (6) communicates with the internal cavities 22 (23) of the hydraulic cylinder 18 (19), and the radial channel 24 of the upper movable rod 5 hermetically closed by the upper packer 1. During the descent of the packing device into the well, spring centralizers 17 center the device relative to the axis of the well.

Having reached the interval of the test formation (not shown), the packer is installed so that the upper packer 1 is above the test formation and the lower packer 2 is below the test formation.

Then, from the wellhead in the pipe string 29, the axial channel 7 (8), excessive pressure (for example 15.0 MPa) is created that enters the internal cavities 22 (23) of the hydraulic cylinder 18 (19) and acts on the annular piston 20 (21), since the bottom of the lower movable rod 6 is provided with a blank partition 9.

Under the action of excess pressure, the annular piston 20 (21) is hermetically moved relative to the hydraulic cylinder 18 (19), compressing the sealing element 3 (4), while the annular piston 20 moves downward and the annular piston 21 upward.

The sealing element 3 (4) is compressed, hermetically pressing against the inner walls of the well (not shown), while the test formation is hermetically insulated both from above and from below.

Further, without relieving excess pressure (15.0 MPa) in the pipe string 29, the axial channel 7 (8) and, accordingly, in the internal cavities 22 (23), since they are hydraulically connected, lower the pipe string 29 down until the radial channel 24 will not come out of tight interaction with the upper packer 1 and will not be installed opposite the hollow filter 10, while the internal cavities 22 (23) are hydraulically cut off from the inner space of the pipe string 29, the axial channel 7 (8) by movable rods 5 (6), forming a hydraulic gate.

In this position, the formation is tested between the upper 1 and lower 2 packers, while the injected fluid through the pipe string 29, the axial channel 5, the radial channel 24 and the hollow filter 10 enters the test formation.

At the end of the formation test, the excess pressure in the pipe string 29, the axial channel 7 (8) is released. The pipe string 29 is lifted up until the packing device returns to its original position (see drawing), while the axial channel 7 (8) of the movable rod 5 (6) communicates with the internal cavities 22 (23) of the hydraulic cylinder 18 (19) and the radial channel 24 of the upper movable rod 5 is hermetically sealed by the upper packer 1. After that, the packing device can be removed to the surface or selectively transferred to another interval of the well for testing the next formation.

The proposed packer device for selective testing of formations has a simple design, as a result of which the material costs of its manufacture are reduced, and the simplified technological process of using the device allows to achieve high-quality sealing and increase the reliability of work in general.

Claims (1)

A packer for selective formation testing, comprising an upper connecting unit for fixing on a pipe string, upper and lower packers with sealing elements, upper and lower movable rods made with axial channels placed in the cavities of the packers, the axial channel of the lower movable rod provided with a blind partition , and a hollow filter installed between the upper and lower packers, characterized in that the upper and lower movable rods are rigidly and hermetically connected to each other, provided with one unit and made with the possibility of moving relative to the upper and lower packers only downward, while the sealing elements of the upper and lower packers are located between the stops, the upper stop of the lower packer is rigidly connected by a hollow filter to the lower stop of the upper packer, which is equipped with spring centralizers from above, and one of the stops of each packer is made in the form of a hydraulic cylinder rigidly connected to the packer, and an annular piston interacting with the sealing element, and the internal cavities of each guide the cylinders are designed to interact with the axial channel of the movable rods above the blank partition and leakproof insulation when moving the movable rods down relative to the packers, while the upper movable rod is provided with a radially sealed upper packer channel that is able to interact with the outer space through the hollow filter when moving the movable rods stocks down relative to the packers.