WO2020034358A1

WO2020034358A1 - Core preservation compartment having constant pressure function

Info

Publication number: WO2020034358A1
Application number: PCT/CN2018/108979
Authority: WO
Inventors: 高明忠; 谢和平; 张茹; 陈领; 张泽天; 张志龙; 鲁义强; 李聪; 何志强; 华夏; 明传剑; 彭高友; 陆彤
Original assignee: 四川大学; 深圳大学
Priority date: 2018-08-13
Filing date: 2018-09-30
Publication date: 2020-02-20
Also published as: CN109113615A; CN109113615B

Abstract

A core preservation compartment having a constant pressure function comprises a mechanical portion and a control portion. The mechanical portion comprises an inner coring barrel (8), an outer coring barrel (6), and an accumulator (29). The accumulator (29) communicates with the outer coring barrel (6) via a pipe. The outer coring barrel (6) is sleeved on the inner coring barrel (8) and is provided with a flap valve (3). The control portion comprises a pressure sensor (5), and a three-way shut-off valve A (210) disposed on the pipe. Two end openings of the three-way shut-off valve A (210) are respectively connected to the accumulator (29) and the outer coring barrel (6). A third end opening of the three-way shut-off valve A (210) is connected to a pressure relief valve (211). The three-way shut-off valve A (210) is an electrically controlled valve. The pressure sensor (5) and the three-way shut-off valve A (210) are connected to a processing unit. The pressure sensor (5) is used to measure the pressure in the preservation container. The invention automatically controls the pressure of a preservation container, thereby facilitating maintenance of a core in an in-situ environment.

Description

Rock core fidelity capsule with constant pressure function

Technical field

The invention relates to the field of oil and gas field exploration, in particular to a rock core fidelity cabin with a constant pressure function.

Background technique

During the exploration of oil and gas fields, cores are important data for discovering oil and gas layers and studying formations, oil layers, reservoirs, caps, structures, etc. Through the observation and study of cores, you can directly understand the lithology and physical properties of underground rocks. And oily, gas, aquatic characteristics. After the oilfield is put into development, it is necessary to further study and understand the sedimentary characteristics of the reservoir through the core, the physical properties, pore structure, wettability, relative permeability, lithofacies of the reservoir, physical simulation of the reservoir, and the law of water flooding in the reservoir; Water flooding characteristics of the reservoirs in the development stage and in different water-cutting stages, to clarify the distribution of remaining oil, and to provide scientific basis for the design of oilfield development schemes, layer system, well pattern adjustment, and infill wells.

Coring is the use of special coring tools to pull underground rocks into the ground during drilling. This type of rock is called a core, which can be used to determine various properties of the rock and intuitively study the underground structure. And rock sedimentary environment, and understand the fluid properties. In the process of mineral exploration and development, it is necessary to carry out drilling according to the stratigraphic level and depth of the geological design. The core tools are drilled into the well, and the core samples are drilled and stored in the core storage compartment. During the ascent, environmental parameters such as the pressure of the core storage compartment will decrease, making the core unable to maintain its state in the in-situ environment.

Summary of the Invention

The invention aims to provide a core fidelity capsule with a constant pressure function, which can automatically control the pressure in the fidelity capsule, which is beneficial for the core to maintain its state in the in-situ environment.

To achieve the above object, the present invention is implemented by using the following technical solutions:

The rock core fidelity capsule with constant pressure function disclosed in the present invention includes a mechanical part and a control part. The mechanical part includes an inner core barrel, an outer core barrel, and an accumulator. The accumulator communicates with the outside through a pipe. A coring cylinder, the outer coring cylinder is sleeved on the inner coring cylinder, and the outer coring cylinder is provided with a flap valve;

The control part includes a pressure sensor, a three-way shut-off valve A provided on the pipeline, two ports of the three-way shut-off valve A are respectively connected to an accumulator and an external core, and a third port of the three-way shut-off valve A A pressure relief valve is connected, and the three-way stop valve A is an electric control valve. The pressure sensor and the three-way stop valve A are both connected to a processing unit. The pressure sensor is used to detect the pressure in the fidelity cabin.

Further, the present invention also includes a pressure gauge, which is connected to the outer core barrel through a three-way stop valve B.

Further, a graphene layer is attached to an inner wall of the inner core cylinder.

Further, the upper part of the inner core tube is filled with a dripping film-forming agent.

Preferably, the flap valve includes a valve seat and a valve disc, and the valve disc includes an elastic sealing ring, an elastic connecting bar, a sealing member, and a plurality of locking bars arranged in parallel in sequence. The elastic connecting bar connects all the locking bars in series and All the lock bars are hooped together by the elastic sealing ring to form an integrated structure. The lock bar has a card slot adapted to the elastic seal ring. The elastic seal ring is installed in the card slot, and a seal is provided between two adjacent lock bars. One end of the valve flap is movably connected to the upper end of the valve seat through a limit hinge; the valve flap is curved when it is not turned down, and the valve flap is in conformity with the outer wall of the inner core barrel; the valve flap is flat and covered when it is turned down. Upper end of valve seat.

Further, a sealing cavity is provided on an inner wall of the outer coring cylinder, the flap is located in the sealing cavity, and the sealing cavity is in communication with the inner coring cylinder.

Further, a sealing ring is provided on the inner wall of the outer core barrel, and the sealing ring is located below the flap valve.

Preferably, the inner core barrel is made of PVC.

Preferably, the power source of the control part is located on the outer core barrel.

The principle of the present invention is as follows: the pressure in the fidelity cabin is detected in real time by a pressure sensor, and compared with the in-situ pressure of the core tested in advance, according to the difference between the two pressures, the on-off of the three-way shut-off valve A is controlled, so that the The pressure in the true cabin is increased to maintain the same as the core in-situ pressure. Because the environmental pressure of the fidelity cabin during the lifting process is gradually reduced, the core in-situ pressure is greater than the environmental pressure of the fidelity cabin during the lift process. Therefore, pressurization measures can be used.

The beneficial effects of the present invention are as follows:

1. The invention can automatically pressurize the fidelity cabin, which is beneficial to the core to maintain its state in the in-situ environment.

2. The flap mechanism of the present invention can automatically close the fidelity compartment when the coring is completed, and has a simple structure, safety and reliability.

3. The graphene layer of the present invention can reduce the sliding resistance of the rock core on the inside of the PVC pipe, at the same time improve the strength and surface accuracy of the inside, and enhance the thermal conductivity.

4. The sealed cavity of the present invention can isolate the drilling fluid passing through the fidelity cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of the present invention;

2 is a schematic structural diagram of a flap valve when it is not turned down;

3 is a schematic structural diagram of a flap valve when it has been turned down;

4 is a schematic structural diagram of a valve disc;

5 is a schematic structural diagram of a sealed cavity;

Figure 6 is a partial cross-sectional view of an inner core barrel;

FIG. 7 is an electrical schematic diagram of the present invention.

detailed description

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings.

The rock core fidelity capsule with constant pressure function disclosed in the present invention includes a mechanical part and a control part. As shown in FIG. 1, the mechanical part includes an inner core barrel 8, an outer core barrel 6 and an energy accumulator 29. The device 29 communicates with the outer core barrel through a pipe. The inner core barrel 8 is used to place the core 1. The outer core barrel 6 is set on the inner core barrel 6. The upper end of the inner core barrel 8 is connected to one end of the pipeline. One end is connected to a liquid nitrogen storage tank 25, and an electric control valve 26 is provided on the pipeline. The liquid nitrogen storage tank 25 is located inside the outer core cylinder 6, and the outer core cylinder 6 is provided with a flap valve 3.

Specifically, as shown in FIG. 2, FIG. 3, and FIG. 4, the flap valve 3 includes a valve seat 36 and a valve disc 37, and the valve disc 37 includes an elastic sealing ring 34, an elastic connecting bar 32, a seal, and a plurality of parallel arrays in order. The lock strip 35 and the elastic connecting strip 32 connect all the lock strips 35 in series and hoop all the lock strips 35 together by the elastic seal ring 34 to form an integrated structure. The lock strip 35 has a slot 31 adapted to the elastic seal ring. An elastic seal ring 34 is installed in the slot 31, and a seal is provided between two adjacent lock bars 35. One end of the valve flap 3 is movably connected to the upper end of the valve seat 36 through a limit hinge 33. The valve flap 37 is In an arc shape, the valve flap 37 fits on the outer wall of the inner core barrel 8; the valve flap 37 is flat and covers the upper end of the valve seat 36 when it is turned down.

As shown in FIG. 7, the control part includes a pressure sensor 5, a three-way stop valve A210 provided on the pipeline, and two ports of the three-way stop valve A210 are connected to the accumulator 29 and the outer core 6, respectively. The three-way stop valve The third port of A210 is connected to a pressure relief valve 211. The three-way stop valve A210 is an electronically controlled valve. The pressure sensor 5 and the three-way stop valve A210 are connected to a processing unit. The pressure sensor 5 is used to detect the pressure in the fidelity cabin. The invention also includes a pressure gauge 212, which communicates with the outer core through a three-way stop valve B213.

As shown in FIG. 5, the inner wall of the outer coring cylinder 6 is provided with a sealing cavity 39, the flap is located in the sealing cavity, and the sealing cavity is in communication with the inner coring cylinder.

As shown in FIG. 6, the inner core cylinder 8 is made of PVC. The inner wall of the inner core cylinder 8 is attached with a graphene layer 81. The upper part of the inner core cylinder 8 is filled with a drip film-forming agent 82, which is located below the piston 7. .

Of course, the present invention may have various other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications according to the present invention, but these corresponding changes All modifications and variations shall fall within the protection scope of the appended claims.

Claims

The core fidelity capsule with constant pressure function is characterized in that it includes a mechanical part and a control part. The mechanical part includes an inner core barrel, an outer core barrel, and an accumulator. The accumulator communicates with the outside through a pipe. A coring cylinder, the outer coring cylinder is sleeved on the inner coring cylinder, and the outer coring cylinder is provided with a flap valve;

The control part includes a pressure sensor, a three-way shut-off valve A provided on the pipeline, two ports of the three-way shut-off valve A are respectively connected to an accumulator and an external core, and a third port of the three-way shut-off valve A A pressure relief valve is connected, and the three-way stop valve A is an electric control valve. The pressure sensor and the three-way stop valve A are both connected to a processing unit. The pressure sensor is used to detect the pressure in the fidelity cabin.
The rock core fidelity capsule with constant pressure function according to claim 1, further comprising a pressure gauge, wherein the pressure gauge communicates with the outer core barrel through a three-way stop valve B.
The rock core fidelity capsule with a constant pressure function according to claim 1, wherein a graphene layer is attached to an inner wall of the inner core barrel.
The rock core fidelity capsule with a constant pressure function according to claim 2, wherein the upper part of the inner core barrel is filled with a dripping film-forming agent.
The core fidelity capsule with constant pressure function according to any one of claims 1-4, wherein the flap valve includes a valve seat and a valve disc, and the valve disc includes an elastic sealing ring and an elastic connection. Strips, seals and multiple lock strips arranged in parallel in sequence. The elastic connecting strips connect all the lock strips in series and hoop all the lock strips together by the elastic seal ring to form an integrated structure. A card slot, an elastic sealing ring is installed in the card slot, a seal is provided between two adjacent lock bars, and one end of the valve flap is movably connected to the upper end of the valve seat through a limit hinge; the valve flap is curved when it is not turned down , The valve flap is attached to the outer wall of the inner core barrel; when the valve flap is turned down, it is flat and covers the upper end of the valve seat.
The rock core fidelity capsule with constant pressure function according to claim 5, characterized in that the inner wall of the outer coring cylinder is provided with a sealed cavity, and the flap is located in the sealed cavity, and the sealed cavity and the inner coring core Tube connected.
The rock core fidelity capsule with constant pressure function according to claim 5, characterized in that: an inner wall of the outer core barrel is provided with a seal ring, and the seal ring is located below the flap valve.
The rock core fidelity capsule with constant pressure function according to claim 5, wherein the inner core barrel is made of PVC.
The rock core fidelity capsule with a constant voltage function according to claim 1, wherein the power source of the control part is located on the outer core barrel.