An in-situ tester for permeability of geothermal reservoirs

Abstract

The utility model discloses an underground hot water reservoir permeability in situ tester belongs to the field of instrument equipment, and the cable and the remote transmission module are connected in proper order from top to bottom through the electronic cabin, the first sensor module, the upper packer, the flow injection module, the second sensor module, the lower packer, the sampling module and the guide hammer, and the cable and the remote transmission module are electrically connected with the ground system, and the cooling mechanism is arranged in the electronic cabin, and the cooling mechanism includes the fin that is equidistantly arranged between the electronic module outer periphery and the cabin inner wall, and the fin is provided with the heat exchange pipe, and the heat exchange pipe is connected with the cold source. The utility model effectively avoids the performance attenuation of electronic components caused by high temperature, data drift problem, significantly improves the accuracy and stability of test data, and guarantees the authenticity of permeability parameter representation.

Description

Technical Field

[0001] This utility model relates to the field of instruments and equipment, and in particular to an in-situ permeability tester for underground hot water reservoirs. Background Technology

[0002] As an important carrier of clean energy resources, the permeability parameter of geothermal reservoirs is a core indicator for assessing reservoir development potential and formulating reasonable exploitation plans. Accurate acquisition of this parameter is crucial for the efficient development and scientific utilization of geothermal resources. In-situ testing technology, due to its ability to accurately reflect the permeability characteristics of the reservoir under original operating conditions, has advantages over indirect testing methods such as laboratory core experiments. Therefore, in-situ permeability testing instruments for geothermal reservoirs have become important technical equipment in related fields. However, geothermal reservoirs generally possess complex environmental characteristics of high temperature and high pressure. Existing in-situ testing instruments face significant technical bottlenecks when adapting to such conditions. The core issue lies in the limited high-temperature and high-pressure resistance of the instruments' built-in electronic components. Under the long-term effects of high temperature and high pressure in reservoirs, electronic components are prone to performance degradation and parameter drift, leading to distorted test data and an inability to accurately characterize the true permeability of the reservoir. In extreme cases, high temperature and high pressure can also directly damage electronic components, causing instrument failure. This not only affects the smooth progress of testing and increases testing costs, but may also lead to test interruption due to instrument failure, making it difficult to obtain complete in-situ test data. This restricts the reliability and widespread application of in-situ permeability testing technology for underground hot water reservoirs. Utility Model Content

[0003] The purpose of this invention is to provide an in-situ permeability testing instrument for underground hot water reservoirs, thereby solving the aforementioned problems.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] This utility model discloses an in-situ permeability testing instrument for underground hot water reservoirs, comprising, from top to bottom, an electronic chamber, a primary sensor module, an upper packer, a flow injection module, a secondary sensor module, a lower packer, a sampling module, and a guide hammer, which are connected in series with a remote transmission module via a cable. The cable and the remote transmission module are electrically connected to a ground system. A cooling mechanism is provided inside the electronic chamber, which includes heat sinks equidistantly arranged between the outer periphery of the electronic module and the inner wall of the chamber. Heat exchange tubes are provided on the heat sinks and connected to a cold source.

[0006] Furthermore, the heat exchange tubes are distributed in a serpentine circumference on the heat sink, with one end of each heat exchange tube serving as a medium inlet and a medium outlet, which are connected to the cold source.

[0007] Furthermore, the cold source is nitrogen.

[0008] Furthermore, the cable and remote transmission module are integrated with an optical fiber slip ring.

[0009] Furthermore, both the primary sensor module and the secondary sensor module include a pressure sensor and a temperature sensor. The pressure sensor is a high-temperature, high-pressure silicon piezoresistive pressure sensor or a quartz crystal pressure gauge, and the temperature sensor is a platinum resistance thermometer.

[0010] Furthermore, the sampling module includes a high-temperature resistant plunger pump, a precision control valve, and a high-precision vortex flow meter.

[0011] Furthermore, the guide hammer head adopts a streamlined or hemispherical guide head.

[0012] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0013] This utility model of an in-situ permeability tester for underground hot water reservoirs addresses the core pain point of limited high-temperature resistance of electronic components by adding a cooling mechanism. The heat sinks, evenly distributed between the outer periphery of the electronic module and the inner wall of the chamber, can quickly conduct heat from the electronic module's operation and from the external environment. Combined with the synergistic effect of the heat exchange tubes and the cold source, the temperature inside the electronic chamber can be continuously and stably controlled within the operating range suitable for the electronic components. This effectively avoids performance degradation and data drift caused by high temperatures, significantly improving the accuracy and stability of the test data and ensuring the authenticity of the permeability parameter characterization. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings.

[0015] Figure 1 This is a front view of the in-situ permeability testing instrument for underground hot water reservoirs according to this utility model;

[0016] Figure 2 This is a cross-sectional view of the electronic compartment;

[0017] Figure 3 This is a schematic diagram of a partial structure of the electronic compartment;

[0018] Explanation of reference numerals in the attached diagram: 1. Remote transmission module; 2. Cable; 3. Electronics compartment; 4. Primary sensor module; 5. Upper packer; 6. Flow injection module; 7. Secondary sensor module; 8. Lower packer; 9. Sampling module; 10. Guide hammer; 11. Cold source;

[0019] 301. Cabin; 302. Electronic module; 303. Heat sink; 304. Heat exchange tube; 305. Medium inlet; 306. Medium outlet. Detailed Implementation

[0020] like Figure 1-3As shown, an in-situ permeability testing instrument for underground hot water reservoirs includes, from top to bottom, an electronic cabin 3, a primary sensor module 4, an upper packer 5, a flow injection module 6, a secondary sensor module 7, a lower packer 8, a sampling module 9, and a guide hammer 10, which are connected in series with a remote transmission module 1 via a cable 2. The cable 2 is electrically connected to the ground system via the remote transmission module 1, enabling power transmission and two-way data communication.

[0021] A cooling mechanism is installed inside the electronic compartment 3. This mechanism includes heat sinks 303 equidistantly installed between the outer periphery of the electronic module 302 and the inner wall of the compartment 301. Heat exchange tubes 304 are mounted on the heat sinks 303 and connected to a cold source 11, which uses nitrogen gas. The heat exchange tubes 304 are arranged in a serpentine circular pattern on the heat sinks 303. One end of each heat exchange tube serves as a medium inlet 305 and a medium outlet 306, which are connected to the cold source 11, forming a circulation channel for the cold source 11. This allows low-temperature nitrogen gas to continuously enter the heat exchange tubes 304 for heat exchange, while simultaneously ensuring the smooth discharge of high-temperature nitrogen gas after heat exchange, thus guaranteeing the continuity of the cooling process.

[0022] Specifically, the heat sinks 303, equidistantly installed between the outer periphery of the electronic module 302 and the inner wall of the cabin 301, achieve uniform heat conduction through their equidistant distribution. This ensures that heat from all areas around the electronic module 302 can be quickly and evenly conducted to the heat sinks 303, avoiding localized heat accumulation and laying the foundation for subsequent efficient heat exchange. Simultaneously, the heat sinks 303 rely on the heat exchange tubes 304 as a cold energy transfer carrier, establishing a core channel for heat exchange. This allows the low-temperature energy from the cold source 11 to efficiently exchange heat with the heat on the heat sinks 303 through the heat exchange tubes 304, achieving rapid heat transfer. Furthermore, the heat exchange tubes 304 employ a serpentine circumferential distribution to extend the heat exchange path and increase the contact area between the heat exchange tubes 304 and the heat sinks 303. The circumferential distribution also covers the entire area of ​​the heat sinks 303, ensuring that all parts of the heat sinks 303 can fully contact and exchange heat with the heat exchange tubes 304, thus improving overall heat exchange efficiency. The cold source 11 utilizes the advantages of nitrogen's stable chemical properties, non-flammability and explosiveness, and stable low-temperature characteristics to ensure the cooling process is safe and reliable, and to prevent the medium in the cold source 11 from undergoing chemical reactions or abnormal physical states under high-temperature conditions, which would affect the cooling effect.

[0023] The cooling process of the cooling mechanism is as follows:

[0024] Cold source 11 enters the heat exchange tube 304 through medium inlet 305. Since the heat exchange tube 304 is serpentine in shape, the nitrogen gas flows along the serpentine path inside the tube, making full contact with the tube wall during this process. At the same time, external heat is transferred to the nitrogen gas inside the tube through the tube wall, and the nitrogen gas absorbs the heat and its temperature rises. Finally, the nitrogen gas that has absorbed the heat is discharged through medium outlet 306 of the heat exchange tube 304, realizing a complete cooling cycle. The cooling is completed by the continuous running of this cycle.

[0025] The cable 2 and the remote transmission module 1 are integrated with an optical fiber slip ring.

[0026] Electronic module 302 is used for the accurate acquisition, processing and analysis of various data during the test, and at the same time completes the coordinated control of other modules to ensure the orderly progress of the test. It can use industrial-grade embedded controllers such as National Instruments (NI)'s CompactRIO series (such as cRIO-904x) or ADVANTECH. These devices have a wide operating temperature range and have strict vibration resistance certification, and can be used in downhole operations.

[0027] Both the primary sensor module 4 and the secondary sensor module 7 include pressure and temperature sensors, enabling real-time and accurate monitoring of pressure and temperature parameters at different locations within the downhole testing area. The pressure sensor employs a high-temperature, high-pressure silicon piezoresistive pressure sensor (Kulite's ETM-375M series, Keller's PA-23X series, or Panasonic's DP-100 series) or a quartz crystal pressure gauge (Quartzdyne's QS series). The temperature sensor uses a platinum resistance thermometer (Pt100, Pt1000), adapted to high-temperature, high-pressure downhole conditions, providing crucial basic parameter support for permeability calculations.

[0028] The upper packer 5 and lower packer 8 adopt cable-set bridge plugs / test packers, such as Schlumberger's "PCS" (Production Completion System) packer. Their function is to accurately set the packer at both ends of the target layer to form independent test chambers, while isolating the upper control and communication module from the lower test execution module, and providing flexible installation and configuration space for the intermediate functional modules, thereby improving the overall reliability and adaptability of the testing instrument.

[0029] The sampling module 9 includes a high-temperature resistant plunger pump (Teledyne ISCO 100DM or 260D series), a precision control valve (The Lee Company LHDA or INCH series), and a high-precision vortex flow meter (FMC Technologies), enabling stable sampling, precise flow control and measurement of underground hot water reservoir fluids, ensuring the reliability of the sampling process and the accuracy of the sampling data, and providing qualified fluid samples and flow parameters for subsequent reservoir characteristic analysis.

[0030] The guide hammer 10 adopts a streamlined or hemispherical guide head to reduce the frictional resistance between the instrument and the well wall during the instrument's descent into the well, while enhancing the instrument's guidance in the downhole fluid, preventing the instrument from getting stuck or deviating, and ensuring that the instrument can smoothly reach the designated test position.

[0031] The working process of this utility model is as follows:

[0032] First, before testing, the instrument assembly and debugging, as well as the cooling mechanism check inside the electronic compartment 3, are completed. Then, the instrument is lowered into the designated test area using the guide hammer 10, and the cooling mechanism of the electronic compartment 3 is activated simultaneously to ensure the stable operation of the electronic module 302. After arriving at the area, the upper packer 5 and lower packer 8 are controlled by the electronic module 302 to seal the test section, and the first-level sensor module 4 and second-level sensor module 7 are started to collect pressure and temperature data. After the parameters stabilize, the flow injection module 6 is controlled to inject fluid and the sampling module 9 is started to complete sampling and flow measurement. The sensors continuously monitor the data and transmit it to the electronic module 302 for processing. The processed data is transmitted in real time to the ground system via the fiber optic slip ring integrated with the remote transmission module 1 through the cable 2. After the data acquisition is complete and stable, the upper packer 5 and lower packer 8 are controlled to unseal and the instrument is pulled out of the well, completing the test.

[0033] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. An in-situ permeability testing instrument for underground hot water reservoirs, characterized in that: The system includes an electronic cabin (3), a primary sensor module (4), an upper packer (5), a flow injection module (6), a secondary sensor module (7), a lower packer (8), a sampling module (9), and a guide hammer (10) connected in series from top to bottom to the remote transmission module (1) via a cable (2). The cable (2) is electrically connected to the ground system via the remote transmission module (1). The electronic cabin (3) is equipped with a cooling mechanism, which includes heat sinks (303) equidistantly arranged between the outer periphery of the electronic module (302) and the inner wall of the cabin (301). Heat exchange tubes (304) are provided on the heat sinks (303), and the heat exchange tubes (304) are connected to a cold source (11).

2. The in-situ permeability testing instrument for underground hot water reservoirs according to claim 1, characterized in that: The heat exchange tube (304) is distributed in a serpentine circumference on the heat sink (303). One end of the heat exchange tube (304) is a medium inlet (305) and a medium outlet (306). The medium inlet (305) and the medium outlet (306) are connected to the cold source (11).

3. The in-situ permeability testing instrument for underground hot water reservoirs according to claim 1, characterized in that: The cold source (11) is nitrogen.

4. The in-situ permeability testing instrument for underground hot water reservoirs according to claim 1, characterized in that: The cable (2) and the remote transmission module (1) are integrated with an optical fiber slip ring.

5. The in-situ permeability testing instrument for underground hot water reservoirs according to claim 1, characterized in that: Both the primary sensor module (4) and the secondary sensor module (7) include a pressure sensor and a temperature sensor. The pressure sensor is a high-temperature, high-pressure silicon piezoresistive pressure sensor or a quartz crystal pressure gauge, and the temperature sensor is a platinum resistance thermometer.

6. The in-situ permeability testing instrument for underground hot water reservoirs according to claim 1, characterized in that: The sampling module (9) includes a high-temperature resistant plunger pump, a precision control valve, and a high-precision vortex flow meter.

7. The in-situ permeability testing instrument for underground hot water reservoirs according to claim 1, characterized in that: The head of the guide hammer (10) adopts a streamlined or hemispherical guide head.

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