Gas in-situ sampling device suitable for medium-high temperature geothermal field

Abstract

The invention relates to the technical field of gas sampling, in particular to a gas in-situ sampling device suitable for a medium-high temperature geothermal field, the core of the gas in-situ sampling device is a sealed cabin, and the sealed cabin is internally integrated with a pressure stabilizing and separating unit which comprises a gas-liquid separating chamber with a lower inlet and an upper outlet so as to realize gas-liquid separation by utilizing gravity settling; at least one forevacuum sampling bottle for containing samples and at least one purging bottle pre-filled with high-pressure inert gas are arranged on the disc type magazine; the rotary positioning module is used for rotating the disc type magazine so as to align the bottle opening of the sampling bottle or the purging bottle to the outlet of the pressure stabilizing and separating unit; and the linear butt joint module is used for pushing the selected sampling bottle or purging bottle, so that the bottle opening of the selected sampling bottle or purging bottle is in butt joint with the outlet of the pressure stabilizing and separating unit. According to the embodiment of the invention, through cooperative operation of the rotary positioning module and the linear docking module in the sealed cabin, automatic operation of single-time well descending and multiple sampling is realized.

Description

Technical Field

[0001] This invention relates to the field of gas sampling technology, and specifically to an in-situ gas sampling device suitable for medium- and high-temperature geothermal fields. Background Technology

[0002] Medium- and high-temperature geothermal fields refer to geothermal resource areas with temperatures between 60 and 150°C. When exploring and developing such geothermal fields, obtaining the accurate composition of the gases inside is crucial.

[0003] Currently, the main problems with geothermal gas sampling methods are as follows: One method is to transport the gas from the well to the surface through pipelines for sampling. However, this method can easily cause changes in gas composition due to the pressure and temperature drop caused by long-distance transportation, resulting in low sample fidelity.

[0004] Another method is in-situ sampling, which involves lowering a single sampling cylinder to the target formation in the geothermal field. While this method avoids the problem of long-distance transportation, it suffers from the drawback of being able to obtain only one sample per well run, resulting in extremely low sampling efficiency. Furthermore, the sampling cylinder is directly exposed to a high-temperature and high-pressure environment, which may affect the stability of the sample and damage the equipment. In addition, multiple deployments of the device cause significant disturbance to the formation fluids.

[0005] Therefore, how to achieve multiple samplings in situ from a single well run in a geothermal field while ensuring high sample fidelity is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a gas in-situ sampling device suitable for medium- and high-temperature geothermal fields, so as to solve the technical problems of low fidelity and low efficiency in geothermal gas sampling in the prior art.

[0007] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: A gas in-situ sampling device suitable for medium- and high-temperature geothermal fields includes a sealed chamber and a device disposed inside the sealed chamber: A pressure stabilization and separation unit includes a gas-liquid separation chamber with a lower inlet and an upper outlet to achieve gas-liquid separation by gravity settling; A disc-shaped magazine is provided with at least one pre-vacuum sampling bottle for holding samples and at least one purge bottle pre-filled with high-pressure inert gas. A rotary positioning module is used to rotate the disc-shaped magazine to align the mouth of the sampling bottle or the purge bottle with the outlet of the pressure stabilizing and separating unit. And a linear docking module for pushing the selected sampling bottle or the purge bottle so that its bottle mouth docks with the outlet of the pressure stabilization and separation unit; The outlet of the pressure stabilizing and separating unit, the mouth of the sampling bottle, and the mouth of the purge bottle are configured to form a sealed connection under the push of the linear docking module. The mouth of the sampling bottle, the mouth of the purge bottle, and the outlet of the pressure stabilizing and separating unit are all provided with air nozzles that can only be opened when docked. When the sampling bottle is connected to the outlet of the pressure stabilization and separation unit, the gas phase in the formation multiphase fluid separated by the pressure stabilization and separation unit is guided and flows into the sampling bottle to complete the in-situ gas sampling. When the purge bottle is connected to the outlet of the pressure stabilization and separation unit, the high-pressure inert gas released from the purge bottle is guided and flows in the opposite direction through the pressure stabilization and separation unit to complete the cleaning of the pressure stabilization and separation unit.

[0008] Furthermore, the disc-shaped magazine includes: Several longitudinal sliders are evenly distributed around a vertical central axis and can slide parallel to the central axis. Each longitudinal slider is detachably connected to a sampling bottle or a purge bottle.

[0009] Furthermore, the rotation positioning module includes: A rotary actuator is fixedly connected to the sealed chamber, and its actuator is parallel to the central axis of the longitudinal slide rail; A first annular slide rail is fixedly connected to the sealed chamber and coaxially disposed on the outer ring of the actuator of the rotary drive. The annular slide rail has a notch that allows a longitudinal slider to pass vertically through and is slidably connected to all the remaining longitudinal sliders. Furthermore, the linear docking module includes: A second annular slide rail is provided at the notch of the first annular slide rail and can slide parallel to the axis of the rotary driver. During vertical sliding, the second annular slide rail can be spliced ​​with the first annular slide rail to form a complete circular shape. A linear actuator is fixedly connected to the sealed chamber, and the actuator of the linear actuator is fixedly connected to the second annular slide rail.

[0010] Furthermore, it also includes a front-end purification and temperature control unit, whose inlet is located outside the sealed chamber and whose outlet is connected to the inlet of the pressure stabilization and separation unit. The front-end purification and temperature control unit is used to filter and passively cool the downhole fluid entering the device.

[0011] Furthermore, the front-end purification and temperature control unit includes: A sampling head is installed outside the sealed chamber; The filter installed inside the sealed chamber has its inlet connected to the outlet of the sampling head; The heat exchange flow path located inside the sealed chamber has its inlet connected to the outlet of the filter and its outlet connected to the inlet of the pressure stabilization and separation unit. The heat exchange flow path achieves passive cooling of the multiphase fluid flowing through the formation through heat exchange with the main body of the device.

[0012] Furthermore, the front-end purification and temperature control unit also includes: An end cap is slidably connected to the sealed chamber, the end cap being used to open the inlet of the front-end purification and temperature control unit during sampling or purging, and to close the inlet at other times.

[0013] Furthermore, the end cap is fixedly connected to the execution unit of the linear docking module.

[0014] Furthermore, it also includes an environmental stress compensation unit, which comprises: A compensation cavity is connected to the sealed chamber; A piston component is disposed inside the compensation cavity, dividing the compensation cavity into a passive pneumatic cavity and an active pneumatic cavity, wherein the disc-shaped magazine, the rotary positioning module and the linear docking module are located inside the passive pneumatic cavity; A high-pressure gas cylinder filled with high-pressure gas. An electrically controlled three-way valve connects the high-pressure gas cylinder, the active pressure chamber, and the external environment; The electrically controlled three-way valve is electrically connected to the controller, which controls the switching of the valve's path, thereby causing the high-pressure gas cylinder to pressurize the active pressure chamber or depressurize the active pressure chamber to the outside, thus changing the internal pressure of the passive pressure chamber.

[0015] Furthermore, the pressure stabilization and separation unit also includes a mechanism for actively controlling the internal pressure of the gas-liquid separation chamber: An electrically controlled regulating valve is installed at the inlet of the gas-liquid separation chamber; A pressure sensor for monitoring the pressure inside the gas-liquid separation chamber; The electrically controlled regulating valve and the pressure sensor are electrically connected to the controller, which controls the opening degree of the electrically controlled regulating valve based on the pressure signal transmitted by the pressure sensor.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The embodiments of the present invention provide a stable working environment for the core components that is close to the downhole environmental pressure through a sealed chamber, and perform gas-liquid separation and pressure stabilization on the incoming gas through a pressure stabilization and separation unit, which fundamentally avoids the distortion of sample components caused by drastic changes in pressure and temperature, and ensures the originality and accuracy of the sample.

[0017] The embodiments of the present invention achieve the capability of single well entry, automation, and multiple sampling through the coordinated operation of the disc-type ammunition magazine, the rotary positioning module, and the linear docking module, which greatly improves operational efficiency and reduces exploration costs.

[0018] In the embodiments of the present invention, the core precision electromechanical module is protected in a sealed chamber from direct damage by downhole high temperature, high pressure and corrosive fluids. At the same time, the core flow path is cleaned by reverse purging with a purge bottle, which effectively prevents cross-contamination between samples and ensures long-term stable operation of the device and data quality. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0020] Figure 1 This is a top view of an embodiment of the present invention; Figure 2 This is a cross-sectional view of an embodiment of the present invention; Figure 3 for Figure 2 Another operating condition; Figure 4 This is a perspective view of an embodiment of the present invention; Figure 5 This is a perspective view of a specific structure according to an embodiment of the present invention.

[0021] The labels in the diagram represent the following: 1-Sealed chamber; 2-Pressure stabilization and separation unit; 21-Gas-liquid separation chamber; 22-Electrically controlled regulating valve; 3-Disc-type magazine; 31-Longitudinal slider; 4-Rotary positioning module; 41-Rotary actuator; 42-First annular slide rail; 5-Linear docking module; 51-Second annular slide rail; 52-Linear actuator; 6-Front-end purification and temperature control unit; 61-Sampling head; 62-Filter; 63-Heat exchange flow path; 64-End cap; 7-Ambient pressure compensation unit; 71-Passive pressure chamber; 72-Active pressure chamber; 73-Piston; 74-High-pressure gas cylinder; 75-Electrically controlled three-way valve. Detailed Implementation

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] This invention provides a gas in-situ sampling device suitable for medium- and high-temperature geothermal fields. It is a downhole tool that can be lowered to a specified depth (target layer) within a geothermal exploration well or production well for operation. Its core structure and workflow are described below.

[0024] refer to Figure 1 , Figure 2 , Figure 3 This invention provides a gas in-situ sampling device suitable for medium- and high-temperature geothermal fields. Its main structure is set inside a high-pressure resistant sealed chamber. The sealed chamber provides a clean and safe physical isolation environment for all core components inside. The core components set inside the sealed chamber include a pressure stabilization and separation unit, a disc-shaped magazine, a rotary positioning module, and a linear docking module.

[0025] The pressure stabilization and separation unit includes a gas-liquid separation chamber with a bottom inlet and top outlet design. Utilizing the principle of gravity sedimentation, the heavier liquid phase component in the fluid settles at the bottom, while the lighter gas phase flows out from the top outlet, thus achieving gas-liquid separation.

[0026] A disc-shaped magazine is a carrier mechanism on which at least one pre-vacuum sampling bottle and at least one purge bottle pre-filled with a high-pressure inert gas (such as nitrogen) can be mounted.

[0027] For further reference, Figure 4 , Figure 5 The specific collaborative structure of the rotary positioning module and the linear docking module is described. These two modules together constitute the automated actuator for bottle selection and docking.

[0028] The rotary positioning module includes a rotary driver (such as a stepper motor) fixed on a sealed chamber, and several longitudinal sliders surrounding and connected to the actuator of the rotary driver. Each longitudinal slider is detachably connected to a sampling bottle or a purge bottle, thereby forming a disc-shaped magazine.

[0029] The rotary positioning module also includes a first annular slide rail, which is fixed to the sealed chamber and coaxially fitted around the outer ring of the rotary drive actuator. The first annular slide rail has a notch.

[0030] During operation, the inner wall of the first annular slide rail is slidably connected to all longitudinal slides except for one slide block, restricting their axial (vertical) movement; while the longitudinal slide block located at the notch is not restricted in this way and can slide freely axially.

[0031] The rotary actuator can selectively align any one of the longitudinal sliders (and the bottle to which it is attached) with the notch by rotating each longitudinal slider.

[0032] The linear docking module closely matches the above structure, and it includes a second annular slide rail and a linear driver.

[0033] The second annular slide rail is structurally designed to fit precisely into the gap of the first annular slide rail and can slide parallel to the axis of the rotary driver (i.e., in the vertical direction). The linear driver is fixed to the sealed chamber, and its actuator is fixedly connected to the second annular slide rail.

[0034] When the linear actuator is activated, it will drive the second annular slide rail to move vertically. Since the selected longitudinal slider is located at the notch and in contact with the second annular slide rail, the longitudinal slider (and the bottle connected to it) will be pushed by the second annular slide rail to complete the linear motion of connecting upward with the outlet of the voltage regulator and separation unit or pulling downward to disengage.

[0035] Further reference Figure 2 , Figure 3 The connection surfaces of the outlet of the pressure stabilization and separation unit, the sampling bottle mouth, and the purge bottle mouth are all constructed to form a reliable sealed connection under the push of the linear docking module.

[0036] During sampling: When a sampling bottle is pushed up and connected to the outlet of the pressure stabilization and separation unit, the pure gas phase processed by the pressure stabilization and separation unit is guided and flows into the pre-vacuum sampling bottle, completing one in-situ gas sampling.

[0037] During purging: When a purging bottle is connected to the outlet, the high-pressure inert gas inside is released and guided to flow in the opposite direction through the pressure stabilization and separation unit. The powerful airflow cleans the residue inside the unit.

[0038] The sampling bottle mouth, the purge bottle mouth, and the outlet of the pressure stabilization and separation unit are all equipped with air nozzles that can only be opened when connected.

[0039] Furthermore, the device preferably also includes a front-end purification and temperature control unit, which is the first barrier for geothermal fluid to enter the device. Its inlet is located outside the sealed chamber, and its outlet is connected to the inlet of the pressure stabilization and separation unit, which is used to filter and passively cool the incoming multiphase fluid from the downhole formation.

[0040] refer to Figure 2 , Figure 3 , Figure 4 , the front-end purification and temperature control unit specifically includes: a sampling head disposed outside the sealed chamber; a filter disposed inside the sealed chamber for filtering out solid impurities in the fluid; and a heat exchange flow path disposed inside the sealed chamber, whose inlet is connected to the outlet of the filter and the outlet is connected to the inlet of the pressure stabilization and separation unit.

[0041] The heat exchange flow path is usually designed as a long and winding pipeline, which increases the contact area and time between the fluid and the device body, and exchanges heat with the device body with a huge heat capacity through heat conduction, thereby achieving passive cooling of the high-temperature fluid.

[0042] Further, referring to Figure 2 , Figure 3 , in order to control the entry of the fluid, the front-end purification and temperature control unit preferably further includes an end cap. The inlet of the sampling head in this embodiment is a plurality of openings surrounding the axis of the sealed chamber, and the end cap is a cylindrical shape capable of covering each opening.

[0043] The end cap can slide relative to the sealed chamber, and its structure is fixedly connected to the execution part of the linear docking module (i.e., the second annular slide rail or the component linked thereto).

[0044] Through this design, when the linear drive pushes the bottle body upward for docking, it will联动 the end cap to open the inlet of the sampling head; when the bottle body is pulled back and disengaged, the end cap will be联动 to close the inlet.

[0045] In this way, the inlet is only opened during sampling or purging, achieving联动 control.

[0046] Further, referring to Figure 2 , Figure 3 , Figure 4 , to achieve high-fidelity sampling of the sample, this device preferably further includes an environmental pressure compensation unit, whose function is to make the internal pressure of the sealed chamber actively adapt to and be basically synchronized with the pressure of the external downhole environment.

[0047] The environmental pressure compensation unit includes: a compensation cavity connected to the sealed chamber; a piston member that divides the compensation cavity into a passive air pressure chamber and an active air pressure chamber, and the main working area is located inside the passive air pressure chamber; a high-pressure gas storage cylinder; and an electronically controlled three-way valve controlled by a controller, which is connected to the high-pressure gas storage cylinder, the active air pressure chamber and the external environment.

[0048] The controller controls the electronically controlled three-way valve to pressurize or depressurize the active air pressure chamber, thereby moving the piston member, changing the volume and internal pressure of the passive air pressure chamber, and enabling it to track the external formation pressure.

[0049] To further ensure a constant sampling pressure, the unit also includes an active pressure control system: an electrically controlled regulating valve located at the cavity inlet and a pressure sensor for monitoring the pressure inside the cavity. Both are electrically connected to the controller. The controller controls the opening of the electrically controlled regulating valve through a closed loop based on the real-time signal from the pressure sensor, thereby accurately stabilizing the pressure inside the cavity at a preset value.

[0050] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A gas in-situ sampling device suitable for medium- and high-temperature geothermal fields, characterized in that, Includes a sealed chamber (1) and disposed inside the sealed chamber (1): A pressure stabilization and separation unit (2) includes a gas-liquid separation chamber (21) with a lower inlet and an upper outlet to achieve gas-liquid separation by gravity settling; A disc-shaped magazine (3) is provided with at least one pre-vacuum sampling bottle for holding samples and at least one purge bottle pre-filled with high-pressure inert gas. A rotary positioning module (4) is used to rotate the disc-shaped magazine (3) to align the mouth of the sampling bottle or the purge bottle with the outlet of the pressure stabilizing and separating unit (2); And a linear docking module (5) for pushing the selected sampling bottle or the purge bottle so that its bottle mouth docks with the outlet of the pressure stabilizing and separating unit (2); The outlet of the pressure stabilizing and separating unit (2), the mouth of the sampling bottle and the mouth of the purge bottle are configured to form a sealed connection under the push of the linear docking module (5). The mouth of the sampling bottle, the mouth of the purge bottle and the outlet of the pressure stabilizing and separating unit (2) are all provided with a nozzle that can only be opened when docking. When the sampling bottle is connected to the outlet of the pressure stabilization and separation unit (2), the gas phase in the formation multiphase fluid separated by the pressure stabilization and separation unit (2) is guided and flows into the sampling bottle to complete the in-situ gas sampling. When the purge bottle is connected to the outlet of the pressure stabilizing and separating unit (2), the high-pressure inert gas released from the purge bottle is guided and flows in the opposite direction through the pressure stabilizing and separating unit (2) to complete the cleaning of the pressure stabilizing and separating unit (2).

2. The gas in-situ sampling device according to claim 1, characterized in that, The disc-shaped magazine (3) includes: Several longitudinal sliders (31) are evenly distributed around a vertical central axis and can slide parallel to the central axis. Each of the longitudinal sliders (31) is detachably connected to a sampling bottle or a purge bottle.

3. The gas in-situ sampling device according to claim 2, characterized in that, The rotation positioning module (4) includes: A rotary actuator (41) is fixedly connected to the sealed chamber (1), and its actuator is parallel to the central axis; A first annular slide rail (42) is fixedly connected to the sealed chamber (1) and coaxially disposed on the outer ring of the actuator of the rotary drive (41). The annular slide rail has a notch that allows a longitudinal slider (31) to pass vertically through and slides through all the remaining longitudinal sliders (31).

4. The gas in-situ sampling device according to claim 3, characterized in that, The linear docking module (5) includes: A second annular slide rail (51) is provided at the notch of the first annular slide rail (42) and can slide parallel to the axis of the rotary driver (41). The second annular slide rail (51) can be spliced ​​with the first annular slide rail (42) to form a complete annular shape during vertical sliding. A linear actuator (52) is fixedly connected to the sealed chamber (1), and the actuator of the linear actuator (52) is fixedly connected to the second annular slide rail (51).

5. The gas in-situ sampling device according to claim 1, characterized in that, It also includes a front-end purification and temperature control unit (6), whose inlet is located outside the sealed chamber (1) and whose outlet is connected to the inlet of the pressure stabilization and separation unit (2). The front-end purification and temperature control unit (6) is used to filter and passively cool the downhole fluid entering the device.

6. The gas in-situ sampling device according to claim 5, characterized in that, The front-end purification and temperature control unit (6) includes: A sampling head (61) is disposed outside the sealed chamber (1); The filter (62) installed inside the sealed chamber (1) has its inlet connected to the outlet of the sampling head (61); The heat exchange flow path (63) is set inside the sealed chamber (1), with its inlet connected to the outlet of the filter (62) and its outlet connected to the inlet of the pressure stabilization and separation unit (2). The heat exchange flow path (63) achieves passive cooling of the multiphase fluid flowing through the formation through heat exchange with the device body.

7. The gas in-situ sampling device according to claim 6, characterized in that, The front-end purification and temperature control unit (6) also includes: An end cap (64) is slidably connected to the sealed chamber (1). The end cap (64) is used to open the inlet of the front-end purification and temperature control unit (6) during sampling or purging, and to close the inlet at other times.

8. The gas in-situ sampling device according to claim 7, characterized in that, The end cap (64) is fixedly connected to the execution part of the linear docking module (5).

9. The gas in-situ sampling device according to claim 1, characterized in that, It also includes an environmental stress compensation unit (7), which comprises: A compensation cavity is connected to the sealed chamber (1); A piston (73) is disposed inside the compensation cavity, dividing the compensation cavity into a passive pneumatic cavity (71) and an active pneumatic cavity (72), wherein the disc-shaped magazine (3), the rotary positioning module (4) and the linear docking module (5) are located inside the passive pneumatic cavity (71); A high-pressure gas cylinder (74) is filled with high-pressure gas. An electrically controlled three-way valve (75) is connected to the high-pressure gas cylinder (74), the active pressure chamber (72), and the external environment; The electrically controlled three-way valve (75) is electrically connected to the controller. The controller is used to control the electrically controlled three-way valve (75) to switch the passage, so that the high-pressure gas cylinder (74) pressurizes the active gas pressure chamber (72) or causes the active gas pressure chamber (72) to release pressure to the outside, thereby changing the internal pressure of the passive gas pressure chamber (71).

10. The gas in-situ sampling device according to claim 1, characterized in that, The pressure stabilization and separation unit (2) also includes a mechanism for actively controlling the internal pressure of the gas-liquid separation chamber (21): An electrically controlled regulating valve (22) is installed at the inlet of the gas-liquid separation chamber (21); A pressure sensor for monitoring the pressure inside the gas-liquid separation chamber (21); The electrically controlled regulating valve (22) and the pressure sensor are electrically connected to the controller, which controls the opening degree of the electrically controlled regulating valve (22) according to the pressure signal transmitted by the pressure sensor.

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