A gas in-situ sampling device suitable for medium-high temperature geothermal fields

Abstract

The present application relates to the technical field of gas sampling, in particular to a gas in-situ sampling device suitable for medium-high temperature geothermal field, which core is a sealed cabin, and the inside of the cabin is integrated with: a stable pressure and separation unit, including a gas-liquid separation chamber with a lower inlet and an upper outlet, so as to realize gas-liquid separation by gravity settling; a disc type ammunition box, at least one pre-vacuum sampling bottle for containing samples and at least one purge bottle pre-filled with high-pressure inert gas are arranged on the disc type ammunition box; a rotary positioning module is used for rotating the disc type ammunition box to align the bottle mouth of the sampling bottle or the purge bottle with the outlet of the stable pressure and separation unit; a linear docking module is used for pushing the selected sampling bottle or purge bottle to complete the docking of the bottle mouth with the outlet of the stable pressure and separation unit. Through the cooperative operation of the rotary positioning module and the linear docking module in the sealed cabin, the automatic operation of single-well drilling and multiple sampling is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas sampling, in particular to a gas in-situ sampling device suitable for medium-high temperature geothermal field. BACKGROUND

[0002] Medium-high temperature geothermal field refers to a geothermal resource area with a temperature of 60-150 DEG C. When exploring and developing such geothermal field, it is crucial to obtain accurate components of the internal gas.

[0003] At present, the sampling methods of geothermal gas mainly have the following problems:

[0004] One way is to transport the downhole gas to the ground through a pipeline for sampling. This method is prone to cause changes in gas components due to pressure and temperature drop caused by long-distance transportation, resulting in low sample fidelity.

[0005] Another way is in-situ sampling, that is, a single sampling cylinder is lowered to the target layer of the geothermal field. Although this method avoids the problem of long-distance transportation, it has the problems of only one sample being obtained per well and extremely low sampling efficiency. At the same time, the sampling bottle is directly exposed to a high-temperature and high-pressure environment, which may affect the sample stability and cause damage to the equipment. In addition, multiple lowering of the device causes great disturbance to the formation fluid.

[0006] Therefore, how to realize one-time lowering and multiple sampling in-situ in the geothermal field and ensure high sample fidelity is a technical problem to be solved in the field. SUMMARY

[0007] The purpose of the present application is to provide a gas in-situ sampling device suitable for medium-high temperature geothermal field, so as to solve the technical problems of low sampling fidelity and low efficiency of geothermal gas in the prior art.

[0008] To solve the above technical problems, the present application specifically provides the following technical solutions:

[0009] A gas in-situ sampling device suitable for medium-high temperature geothermal field, comprising a sealed cabin and a:

[0010] A pressure stabilizing and separating unit, comprising a gas-liquid separation chamber having a lower inlet and an upper outlet, so as to realize gas-liquid separation by gravity settling;

[0011] A disc-type cartridge, at least one pre-vacuum sampling bottle for containing samples and at least one purge bottle pre-charged with high-pressure inert gas are arranged on the disc-type cartridge;

[0012] A rotary positioning module for rotating the disc-type cartridge to align the bottle mouth of the sampling bottle or the purge bottle with the outlet of the pressure stabilizing and separating unit;

[0013] and a linear docking module for pushing the selected sampling bottle or purge bottle to dock its mouth with the outlet of the pressure stabilizing and separating unit;

[0014] wherein 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 pushing of the linear docking module, and each of the mouth of the sampling bottle, the mouth of the purge bottle and the outlet of the pressure stabilizing and separating unit is provided with a gas nozzle that can be opened only when docking;

[0015] when the sampling bottle is docked with the outlet of the pressure stabilizing and separating unit, the gas phase in the formation multiphase fluid separated by the pressure stabilizing and separating unit is guided and flows into the sampling bottle to complete the in-situ sampling of gas;

[0016] when the purge bottle is docked with the outlet of the pressure stabilizing and separating unit, the high-pressure inert gas released from the purge bottle is guided and flows reversely through the pressure stabilizing and separating unit to complete the cleaning of the pressure stabilizing and separating unit.

[0017] Further, the disc type cartridge comprises:

[0018] a plurality of longitudinal sliders uniformly distributed around a vertical central axis and capable of sliding parallel to the central axis, each of the longitudinal sliders being detachably connected to one of the sampling bottles or one of the purge bottles.

[0019] Further, the rotary positioning module comprises:

[0020] a rotary driver fixedly connected to the sealed cabin and having an execution part parallel to the central axis of the longitudinal sliding rail;

[0021] a first annular sliding rail fixedly connected to the sealed cabin and coaxially arranged outside the execution part of the rotary driver, the annular sliding rail having a gap allowing one longitudinal slider to vertically pass through and slidingly connecting all the remaining longitudinal sliders;

[0022] Further, the linear docking module comprises:

[0023] a second annular sliding rail arranged at the gap of the first annular sliding rail and capable of sliding parallel to the axis of the rotary driver, the second annular sliding rail being capable of being spliced with the first annular sliding rail to form a complete annular shape during vertical sliding;

[0024] a linear driver fixedly connected to the sealed cabin, the execution part of the linear driver being fixedly connected to the second annular sliding rail.

[0025] Further, a front-end purification and temperature control unit is further included, an inlet of which is located outside the sealed cabin, and an outlet of which is connected to an inlet of the pressure stabilizing and separating unit, the front-end purification and temperature control unit being used for filtering and passively cooling the downhole fluid entering the device.

[0026] Further, the front-end purification and temperature control unit includes:

[0027] a sampling head arranged outside the sealed cabin;

[0028] a filter arranged inside the sealed cabin, an inlet of which is connected to an outlet of the sampling head;

[0029] a heat exchange flow path arranged inside the sealed cabin, an inlet of which is connected to an outlet of the filter, and an outlet of which is connected to the inlet of the pressure stabilizing and separating unit, the heat exchange flow path passively cooling the formation multiphase fluid flowing therethrough by heat exchange with the device body.

[0030] Further, the front-end purification and temperature control unit further includes:

[0031] an end cover slidingly connected to the sealed cabin, the end cover being used for opening the inlet of the front-end purification and temperature control unit during sampling or purging, and closing the inlet at other times.

[0032] Further, the end cover is fixedly connected to the execution part of the linear docking module.

[0033] Further, an ambient pressure compensation unit is further included, the ambient pressure compensation unit including:

[0034] a compensation cavity connected to the sealed cabin;

[0035] a piston arranged inside the compensation cavity, the compensation cavity being divided into a passive air pressure cavity and an active air pressure cavity by the piston, wherein the disc-type ammunition cartridge, the rotary positioning module and the linear docking module are located inside the passive air pressure cavity;

[0036] a high-pressure gas cylinder filled with high-pressure gas inside;

[0037] an electrically-controlled three-way valve connected to the high-pressure gas cylinder, the active air pressure cavity and the external environment;

[0038] wherein the electrically-controlled three-way valve is electrically connected to a controller, the controller being used for controlling the electrically-controlled three-way valve to switch the passage, so that the high-pressure gas cylinder pressurizes the active air pressure cavity or the active air pressure cavity discharges to the outside, thereby changing the internal pressure of the passive air pressure cavity.

[0039] Further, the pressure stabilizing and separating unit further comprises a pressure sensor for monitoring the pressure inside the gas-liquid separating chamber.

[0040] An electrically controlled regulating valve arranged at the inlet of the gas-liquid separating chamber;

[0041] A pressure sensor for monitoring the pressure inside the gas-liquid separating chamber;

[0042] The electrically controlled regulating valve and the pressure sensor are electrically connected with a controller, and the controller is configured to control the opening degree of the electrically controlled regulating valve according to the pressure signal transmitted by the pressure sensor.

[0043] Compared with the prior art, the present application has the following beneficial effects:

[0044] The embodiments of the present application provide a stable working environment similar to the downhole environment pressure for the core assembly in the sealed cabin, and the gas-liquid separation and pressure stabilization are performed on the entering gas by the pressure stabilizing and separating unit, so that the sample component distortion caused by the dramatic change of pressure and temperature is fundamentally avoided, and the originality and accuracy of the sample are ensured.

[0045] The embodiments of the present application realize the single-well, automatic and multiple sampling capacity through the cooperative work of the disc type cartridge, the rotary positioning module and the linear docking module, so that the operation efficiency is greatly improved and the exploration cost is reduced.

[0046] The core precision electromechanical module of the embodiments of the present application is protected in the sealed cabin and is free from the direct damage of the high temperature, high pressure and corrosive fluid in the downhole, meanwhile, the core flow path is cleaned by reverse purging by the purging bottle, so that the cross contamination between the samples is effectively prevented, and the long-term stable operation of the device and the data quality are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only exemplary, and other drawings can be obtained by the provided drawings without creative labor for those skilled in the art.

[0048] Figure 1 is a top view of the embodiment of the present application;

[0049] Figure 2 is a sectional view of the embodiment of the present application;

[0050] Figure 3 is another working condition of Figure 2 ;

[0051] Figure 4A perspective view of a specific structure of an embodiment of the present application.

[0052] Figure 5 A perspective view of a specific structure of an embodiment of the present application.

[0053] The reference numerals in the figures represent the following respectively:

[0054] 1 - sealed cabin; 2 - pressure stabilizing and separating unit; 21 - gas-liquid separation chamber; 22 - electrically controlled regulating valve; 3 - disc type cartridge; 31 - longitudinal sliding block; 4 - rotary positioning module; 41 - rotary driver; 42 - first annular sliding rail; 5 - linear docking module; 51 - second annular sliding rail; 52 - linear driver; 6 - front end purification and temperature control unit; 61 - sampling head; 62 - filter; 63 - heat exchange flow path; 64 - end cover; 7 - environmental pressure compensation unit; 71 - passive air pressure cavity; 72 - active air pressure cavity; 73 - piston; 74 - high pressure gas cylinder; 75 - electrically controlled three-way valve. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0056] The present application provides a gas in-situ sampling device suitable for a medium-high temperature geothermal field, which is a downhole tool that can be lowered to a designated depth (target horizon) in a geothermal exploration well or production well for operation. The core structure and working process are as follows.

[0057] Reference Figure 1 , Figure 2 , Figure 3 The present application provides a gas in-situ sampling device suitable for a medium-high temperature geothermal field, which is a downhole tool that can be lowered to a designated depth (target horizon) in a geothermal exploration well or production well for operation. The core structure and working process are as follows.

[0058] The pressure stabilizing and separating unit includes a gas-liquid separation chamber with a design of lower inlet and upper outlet, which uses the principle of gravity sedimentation to make the heavier liquid phase components in the fluid settle at the bottom, and the lighter gas phase flows out from the top outlet, realizing gas-liquid separation.

[0059] The disc type cartridge is a bearing mechanism, on which at least one pre-vacuum sampling bottle and at least one purge bottle pre-filled with high-pressure inert gas (such as nitrogen) can be installed.

[0060] Further, referring to Figure 4 , Figure 5 , the specific cooperative structure of the rotary positioning module and the linear docking module is described, and the two modules together constitute the automatic execution mechanism of bottle selection and docking.

[0061] The rotary positioning module includes a rotating driver (such as a stepper motor) fixed on the sealed cabin, a plurality of longitudinal sliders surrounding and connected to the execution part of the rotating driver, and each longitudinal slider is detachably connected to a sample bottle or a purge bottle, thereby forming a disc-type ammunition magazine.

[0062] The rotary positioning module further includes a first annular slide rail fixed on the sealed cabin and coaxially sleeved on the outer ring of the execution part of the rotating driver, and the first annular slide rail has a gap.

[0063] In operation, the inner wall of the first annular slide rail is in sliding connection with all longitudinal sliders except one, thereby limiting the axial (vertical) movement of the longitudinal sliders; and the longitudinal slider located at the gap is not limited and can freely slide axially.

[0064] The rotating driver can selectively align any longitudinal slider (and the connected bottle) to the gap position by rotating each longitudinal slider.

[0065] The linear docking module closely matches the above structure, and includes a second annular slide rail and a linear driver.

[0066] The second annular slide rail is structurally filled in the gap of the first annular slide rail and can slide parallel to the axis of the rotating driver (i.e. the vertical direction), and the linear driver is fixed on the sealed cabin and its execution part is fixedly connected with the second annular slide rail.

[0067] When the linear driver operates, it will drive the second annular slide rail to move vertically, and since the selected longitudinal slider is located at the gap and in contact with the second annular slide rail, the longitudinal slider (and the connected bottle) will be pushed by the second annular slide rail to complete the linear movement of upward docking with the outlet of the pressure stabilization and separation unit or downward pulling back to disengage.

[0068] Further, referring to Figure 2 , Figure 3 , the connecting surfaces of the outlet of the pressure stabilization and separation unit, the sample bottle mouth and the purge bottle mouth are configured to form a reliable sealed connection under the pushing of the linear docking module.

[0069] During sampling: when a sample bottle is pushed up and docked with the outlet of the pressure stabilization and separation unit, the purified gas phase treated by the pressure stabilization and separation unit is guided and flows into the pre-vacuum sample bottle, completing one in-situ gas sampling.

[0070] Purging: When a purging bottle is connected to the outlet, the high pressure inert gas inside is released and flows reversely through the pressure stabilizing and separating unit. The strong gas flow will clean the residues inside the unit.

[0071] The bottle mouth of the sampling bottle, the bottle mouth of the purging bottle and the outlet of the pressure stabilizing and separating unit are all provided with a gas nozzle which can be opened only when connected.

[0072] Further, the device preferably further comprises a front-end purification and temperature control unit, which is the first pass of the geothermal fluid into the device. The inlet is located outside the sealed cabin, and the outlet is connected to the inlet of the pressure stabilizing and separating unit, for filtering and passive cooling of the downhole formation multiphase fluid.

[0073] Reference Figure 2 , Figure 3 , Figure 4 , the front-end purification and temperature control unit specifically comprises: a sampling head arranged outside the sealed cabin; a filter arranged inside the sealed cabin for filtering solid impurities in the fluid; and a heat exchange flow path arranged inside the sealed cabin, the inlet of which is connected to the outlet of the filter, and the outlet of which is connected to the inlet of the pressure stabilizing and separating unit.

[0074] The heat exchange flow path is usually designed as a long and winding pipe, which increases the contact area and time of the fluid with the device body, and exchanges heat with the device body which has a large heat capacity through heat conduction, thereby achieving passive cooling of the high-temperature fluid.

[0075] Further, with reference to Figure 2 , Figure 3 , in order to control the entry of the fluid, the front-end purification and temperature control unit preferably further comprises an end cover, and the inlet of the sampling head in this embodiment is a plurality of openings around the axis of the sealed cabin, and the end cover is a cylindrical shape capable of covering each opening.

[0076] The end cover can slide relative to the sealed cabin, and its structure is fixedly connected with the execution part of the linear docking module (i.e. the second annular sliding rail or the component linked therewith).

[0077] Through this design, when the linear drive pushes the bottle body upward to dock, the end cover will be linked to open the inlet of the sampling head; when the bottle body is pulled back to disengage, the end cover will be linked to close the inlet.

[0078] In this way, the inlet is only opened during sampling or purging, realizing linkage control.

[0079] Further, with reference to Figure 2 , Figure 3 , Figure 4To realize high-fidelity sampling of the sample, the device preferably further comprises an ambient pressure compensation unit, which functions to enable the internal pressure of the sealed cabin to actively adapt to and substantially synchronize with the pressure of the external downhole environment.

[0080] The ambient pressure compensation unit comprises a compensation cavity connected to the sealed cabin, a piston member separating the compensation cavity into a passive air pressure cavity and an active air pressure cavity, the main working area being located inside the passive air pressure cavity, a high-pressure gas cylinder, and an electrically-controlled three-way valve electrically controlled by the controller, which is connected to the high-pressure gas cylinder, the active air pressure cavity and the external environment.

[0081] The controller moves the piston member by controlling the electrically-controlled three-way valve to charge or discharge the active air pressure cavity, thereby changing the volume and internal pressure of the passive air pressure cavity, so that it can track the external formation pressure.

[0082] To further ensure the constancy of the sampling pressure, the unit further comprises an active pressure control system: an electrically-controlled regulating valve arranged at the inlet of the cavity and a pressure sensor for monitoring the pressure in the cavity, both of which are electrically connected to the controller, and the controller accurately stabilizes the pressure in the cavity at the preset value by closed-loop control of the opening of the electrically-controlled regulating valve according to the real-time signal of the pressure sensor.

[0083] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements shall also be regarded as falling within the protection scope of the embodiments of the present application.

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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