Geothermal well water level monitoring system

Abstract

The invention discloses a geothermal well water level monitoring system which comprises a tripping-in channel formed by connecting a plurality of measuring pipes, and an electric measuring water level gauge probe enters a well from the tripping-in channel for measurement. Every two adjacent measuring pipes are rotationally connected through a connector. The connector comprises a male buckle connector located at the lower end of the measuring pipe and a female buckle connector located at the upper end of the measuring pipe, a plurality of spring pieces are connected to the outer wall of the male buckle connector in a clamped mode, a plurality of check blocks are arranged in the female buckle connector, each check block is provided with a check groove, and the size of the check grooves is matched with that of the spring pieces. The system can effectively solve the problems that transformation of the geothermal well is limited by an existing sleeve, the transformation difficulty of a pump chamber is large, and investment is high, water level observation work is not affected by a pump pipe in the well, a downhole cable and auxiliary accessories, tripping-in work of an observation probe and a data cable is more convenient, and observed data can accurately reflect the mining water level change condition of the geothermal well.

Description

Technical Field

[0001] The invention relates to the technical field of dynamic monitoring of geothermal resource development, and in particular to a geothermal well water level monitoring system. Background Art

[0002] Geothermal well water level monitoring is an important task in the process of geothermal development and utilization, especially in order to strengthen resource management and reasonably balance the use of geothermal resources, so that monitoring work is becoming more and more normalized. Looking back on the dynamic monitoring of geothermal resources over the years, there are mainly the following characteristics: First, geothermal well water level data is mainly obtained through manual monitoring, which is time-consuming and labor-intensive; second, the degree of automated monitoring is low. Due to the high cost of the automated monitoring system, it also has high requirements for well conditions, well site environment and power supply conditions. Most of the existing geothermal well wellhead devices and heating station pump rooms are extremely non-standard, various monitoring facilities and metering equipment are not standard, the measuring pipes are severely corroded, and the service life is short, which affects the acquisition of data, bringing great difficulties to the dynamic monitoring work of water level data, which can only be obtained through manual observation methods. The transformation of geothermal wells generally has problems such as aging wellheads, no measuring pipes or blocked measuring pipes, and the monitoring facilities cannot be transformed or are difficult to transform.

[0003] Most of the geothermal development wells in the existing oilfield mining area are abandoned or disused oil and water wells. After perforation and other transformation processes, they have become geothermal development / recharge wells. Its main feature is that the measuring pipe has been installed in the well, and its measuring pipe diameter is generally between Ф139.7-Ф177.8mm. At present, the water level measurement work is mainly carried out in the measuring pipe of the transformed geothermal well, that is, the measuring line and probe are directly lowered. Because the pump pipe and power cable in the well are often easily entangled with the lowered measuring line or the probe is stuck, the probe cannot reach the liquid level, and even the probe is stuck, and the situation of being unable to measure often occurs. Summary of the invention

[0004] The purpose of the present invention is to provide a measuring pipe system which is convenient for lowering water level observation instruments and tools, and to complete the monitoring of the dynamic and static water levels of the geothermal well without changing the well body structure of the geothermal well and without affecting the normal production of the geothermal well. The system has low cost, does not require complicated production technology, and has a relatively simple construction process for lowering the well. It provides a simple and easy-to-operate observation pipe system for scientific research such as geothermal resource exploration and development and utilization technology research.

[0005] To achieve the above-mentioned purpose, the technical solution of the present application is: a geothermal well water level monitoring system, including a lower entry channel formed by connecting multiple measuring pipes, and the electric water level meter probe enters the well from the lower entry channel for measurement; two adjacent measuring pipes are rotatably connected through a connecting head; the connecting head includes a male connector located at the lower end of the measuring pipe and a female connector located at the upper end of the measuring pipe, the outer wall of the male connector is clamped with multiple spring springs, and the female connector is provided with multiple blocks inside, and each block is provided with a blocking groove, and the size of the blocking groove matches the spring spring.

[0006] Furthermore, four spring springs are evenly clamped on the outer wall of the male connector. When adjacent measuring tubes are connected, the male connector is inserted from the block space into the female connector, and then the two measuring tubes are rotated until the spring springs are stuck in the blocking groove. When lifting the tubes, the two measuring tubes are rotated in the opposite direction to allow the spring springs to exit the blocking groove, thereby achieving separation of the measuring tubes.

[0007] Furthermore, the measuring pipe is connected to the lower pump oil pipe or the water lifting pipe through a hoop.

[0008] Furthermore, the measuring tube adopts a one-way socket-type structure.

[0009] Furthermore, the measuring tube is a seamless steel tube, and is sprayed with high temperature resistant, anti-corrosion, non-toxic paint inside and outside, and the compressive strength is not less than 20Mpa.

[0010] Furthermore, the ferrule is made of Q235 steel bar and is coated with anti-corrosion paint on the outside.

[0011] Furthermore, the measuring pipe is subjected to a ground test for resistance to internal pressure before formal use. 5-6 measuring pipes are selected from multiple measuring pipes, connected through a connector, the bottom measuring pipe is sealed, the top measuring pipe is connected to the pressure relief valve, and a sampling pump or a high-pressure air compressor is used to make the pressure inside the pipe greater than 20Mpa.

[0012] Furthermore, after the ground test is completed, the test tube is assembled, including:

[0013] After measuring the length of each measuring tube, mark it with a serial number;

[0014] The measuring tubes are lowered vertically into the well according to the marked serial numbers. The first measuring tube must be located 10m below the screw pump head. The connection between the measuring tubes above the dynamic liquid level is sealed with high temperature and high pressure sealing grease.

[0015] Each measuring pipe is connected to the lower pump oil pipe or water lifting pipe through a plurality of ferrules;

[0016] Repeat the above steps until the last measuring tube is lowered; the top measuring tube opening is higher than the wellhead, and the bottom measuring tube opening is plugged with a threaded plug.

[0017] As a further step, the electric water level gauge probe is connected to a steel pipe, a lead block is added into the steel pipe to increase the counterweight, and a rubber sleeve is connected to the outer sleeve of the steel pipe.

[0018] As a further step, the electrical water level meter probe is connected to the ground instrument via a cable, and a high-strength thin steel cable is added inside the cable.

[0019] By adopting the above technical solution, the present invention can achieve the following technical effects: the system has incomparable advantages over the traditional direct offline measurement in the well during use, which are mainly manifested in:

[0020] (1) The liquid level is stable and the measurement data is accurate. Since the depth of the measuring pipe is always kept above 10m below the pump head, the influence of the deep well pump on the liquid level can be isolated;

[0021] (2) The measuring pipe is an independent system. Once it is blocked or damaged, it will not cause abnormal operation of the geothermal well;

[0022] (3) The measuring pipe system has the advantage of independent structure and is not affected by the pump pipe in the pump room and the downhole cable, making it very easy to lower the measuring line and the electric water level meter probe;

[0023] (4) The measuring pipe system can be pulled out from the well together with the pump oil pipe or the water pipe, and the faulty measuring pipe can be replaced in time. It can also be reused in other geothermal wells, which not only solves the problem that has troubled the water level observation work for many years, but also greatly improves the work effect and quality.

[0024] (5) The system is low-cost and has a long service life. It can be placed underground for a long time. Since the components of the measuring pipe system are made of commonly used materials, the price is relatively low. At the same time, during the processing and manufacturing process, the processing accuracy requirements for the components are not high, which can save a lot of processing and manufacturing costs.

[0025] (6) The system is easy to operate downhole and can be constructed together with the geothermal well pump operation. No special tools and equipment are required, so the construction cost is more economical.

[0026] The measuring tube system can effectively solve the problem that the transformation of geothermal wells is limited by the existing casing, the pump room transformation is difficult and the investment is high. It makes the water level observation work not affected by the pump pipe, downhole cable and accessories in the well, and makes the lowering of the observation probe and data cable more convenient. The observed data can accurately reflect the changes in the water level of geothermal wells. At the same time, since an open data line system is used in the observation, it can be connected to a variety of instruments and meters, and multi-parameter measurement can be achieved while measuring the water level of the geothermal well. In addition, for the automatic water level monitoring system, since the measuring tube system can be placed in the geothermal well for a long time, it is a relatively independent system, and the monitoring data is not affected by the "disturbance" of geothermal well mining. It can be used not only in mining wells, but also in water level observation of reinjection wells. Therefore, the measuring tube system can be widely promoted and used in the fields of geothermal resource exploration and geothermal well development management. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural schematic diagram of a geothermal well water level monitoring system;

[0028] Explanation of the numbers in the figure: 1. Pump oil pipe or water pipe; 2. Male joint; 3. Spring spring; 4. Female joint; 5. Hoop; 6. Measuring pipe. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] like Figure 1As shown, this embodiment provides a geothermal well water level monitoring system, including a measuring pipe, a connector, and a hoop. The measuring pipe can be a seamless steel pipe with an outer diameter of 40mm and a wall thickness of 6mm, and is sprayed with high-temperature resistant, anti-corrosive, and non-toxic paint inside and outside, and the compressive strength is not less than 20Mpa. The measuring pipe adopts a one-way socket structure, and adjacent measuring pipes are locked and fixed by a connector. The connector is processed with a round steel billet, and its buckle type is designed as an inner flat buckle, which is divided into a male buckle joint and a female buckle joint. The male buckle joint is trapezoidal, and a spring spring is processed every 90° on the side. There are 4 spring springs in total, which are made of high-strength steel plates; the female buckle joint is cylindrical, and 4 blocks are provided inside. There are blocking grooves on the blocks, and the size of the blocking groove matches the spring spring. When connecting, the male buckle joint should be inserted into the female buckle joint according to the block space, and the two measuring pipes should be rotated until the spring spring is stuck in the blocking groove; when starting the pipe, the two measuring pipes are rotated in the opposite direction to make the spring spring exit the blocking groove to achieve the separation of the measuring pipes. The ferrule can be made of Q235 steel bar, with anti-corrosion paint applied on the outside to prevent corrosion. It has a simple structure and is easy to process.

[0031] Before using the above-mentioned measuring pipes, a ground test of internal pressure resistance must be carried out to obtain a feasibility data analysis report. Only after the report is qualified can it be put into use. The ground test method is: select 5-6 measuring pipes from multiple measuring pipes, connect them through connectors, seal the bottom measuring pipe, connect the top measuring pipe to the pressure relief valve, and use a sampling pump or a high-pressure air compressor to make the pressure inside the pipe greater than 20Mpa to meet the design requirements of the water level monitoring system.

[0032] After the ground test is completed, the test pipe is assembled, including:

[0033] 1) Before lowering the pipe, measure the length of each measuring pipe and mark them with serial numbers for easy installation;

[0034] 2) The measuring tubes are lowered vertically into the well according to the marked serial numbers. The first measuring tube must be located 10m below the screw pump head. Each connector must be firmly connected and cannot be loosened. The connecting parts between the measuring tubes above the dynamic liquid level must be sealed with high temperature and high pressure sealing grease.

[0035] 3) Each measuring pipe is connected to the lower pump oil pipe or water lifting pipe through multiple ferrules. The number of ferrules can be appropriately adjusted according to the depth of the measuring pipe to ensure that the measuring pipe will not move up and down, causing the joint or part of the measuring pipe to fall into the well;

[0036] 4) Repeat the above steps until the last measuring pipe is lowered. The top measuring pipe opening is generally about 1m higher than the wellhead, and the bottom measuring pipe opening is plugged with a screw plug to ensure the sealing effect in the well.

[0037] 5) The measuring tube can be pulled out together with the oil pipe or water pipe. After pulling out, check the spring shrapnel of the connector one by one and replace the failed shrapnel connector in time to ensure the quality of the measuring tube downhole.

[0038] The electric water level gauge probe and the downhole cable are necessary to be modified: the electric water level gauge probe is connected to the steel pipe, and a lead block is added to the steel pipe to increase the counterweight. The steel pipe is covered with a rubber sleeve to ensure that the probe will not collide with the measuring pipe during the rapid lowering process to produce sparks, causing the natural gas in the well to explode when it encounters fire; the downhole cable uses multiple sets of data lines that can transmit temperature electrical signals. At the same time, in order to enhance the tensile strength, a high-strength thin steel cable can be added to the cable. The strength of the steel cable can be selected according to the downhole depth. The probe and the cable are connected with a quick connector to achieve rapid switching of probes for different purposes; the ground instrument can use a multi-functional instrument that can not only display the depth, but also display information such as temperature and conductivity.

[0039] Example

[0040] The above system has been fully applied in the pumping / recharge test of the Huan Sanlianjin 2-6-311 geothermal well. From the perspective of this construction, the lowering of the measuring pipe does not affect the next step of construction. In order to verify the relationship between the water level in the measuring pipe and the water level in the wellbore, the well was subjected to three pressure reduction tests with different depths. In the test, a screw pump was used to pump water, the flow was observed through a triangular weir box, and the water level was measured using an electric water level gauge probe. When measuring the water level, two measuring lines were used to measure the water level value in the wellbore and the water level value in the measuring pipe respectively. All test data were collected and the length of the measuring line was calibrated. The water temperature was observed by the electric water level gauge probe and the air temperature was observed by the mercury thermometer. The duration of each drop was 580, 1800, and 4800 minutes, respectively, and the stabilization time reached 8, 16, and 24 hours, respectively.

[0041] Data correction: During the exploitation of geothermal wells, especially in the early stage of exploitation, the wellhead temperature is not constant, but increases with time. The density of water is inversely proportional to the change in temperature, resulting in the observed water level not being able to truly reflect the change in the actual water level (heat storage pressure) of the geothermal well. At this time, although the water level in the geothermal well rises or remains unchanged, the heat storage pressure decreases. This phenomenon is called the "wellbore effect". Therefore, a unified temperature correction is required to eliminate the wellbore effect. Due to the conduction and diffusion characteristics of heat, the temperature and depth in the geothermal well can be considered to be linearly related. The corrected water level for the depressurization test can be calculated by the following formula. Based on the empirical values ​​of the wellhead temperature and temperature loss, the highest temperature of the depressurization test, 67°C, was used as the unified temperature to correct the experimental observation data.

[0042]

[0043] Where: h is the corrected water level depth, unit: m;

[0044] H: The depth of the midpoint of the water intake section, in m;

[0045] h i Observed water level (the total dynamic water level obtained during the test), unit: m;

[0046] h0 base point height (the ground is the base point, the value is 0), unit is m;

[0047] ρ 平 Average density of water column in geothermal well, kg / m 3 ;

[0048] ρ 高 Heat reservoir temperature corresponds to density, unit kg / m 3

[0049] Compared with the direct measurement in the well, the water level depth is basically consistent, with an error rate of less than 1%. It fully meets the technical requirements of geothermal well pumping test.

[0050] It should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0051] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A geothermal well water level monitoring system, characterized in that: It comprises a lowering channel formed by connecting a plurality of measuring tubes, and the electric water level meter probe enters the well from the lowering channel for measurement; two adjacent measuring tubes are rotatably connected via a connector; the connector comprises a male connector located at the lower end of the measuring tube and a female connector located at the upper end of the measuring tube, a plurality of spring spring sheets are clamped on the outer wall of the male connector, a plurality of blocks are arranged inside the female connector, and a block groove is opened on each block, and the size of the block groove matches the spring spring sheet.

2. A geothermal well water level monitoring system according to claim 1, characterized in that: The outer wall of the male buckle joint is evenly clamped with 4 spring springs. When adjacent measuring tubes are connected, the male buckle joint is inserted from the empty space of the stop block into the female buckle joint, and the two measuring tubes are rotated until the spring springs are stuck in the blocking groove; when lifting the tube, the two measuring tubes are rotated in the opposite direction to make the spring springs withdraw from the blocking groove, thereby realizing the separation of the measuring tubes.

3. A geothermal well water level monitoring system according to claim 1, characterized in that: The measuring pipe is connected with the lower pump oil pipe or the water lifting pipe through a hoop.

4. A geothermal well water level monitoring system according to claim 1, characterized in that: The measuring pipe adopts a one-way socket-and-spigot structure.

5. A geothermal well water level monitoring system according to claim 3, characterized in that: The measuring tube is a seamless steel tube, and is sprayed with high temperature resistant, anti-corrosion, non-toxic paint inside and outside, and the compressive strength is not less than 20Mpa.

6. A geothermal well water level monitoring system according to claim 1, characterized in that: The ferrule is made of Q235 steel bar and coated with anti-corrosion paint on the outside.

7. A geothermal well water level monitoring system according to claim 1, characterized in that: The measuring pipe is subjected to a ground test for resistance to internal pressure before formal use. 5-6 measuring pipes are selected from multiple measuring pipes, connected through a connector, the bottom measuring pipe is sealed, the top measuring pipe is connected to the pressure relief valve, and a sampling pump or a high-pressure air compressor is used to make the pressure inside the pipe greater than 20Mpa.

8. A geothermal well water level monitoring system according to claim 7, characterized in that: After the ground test is completed, the test pipe is assembled, including: After measuring the length of each measuring tube, mark it with a serial number; The measuring tubes are lowered vertically into the well according to the marked serial numbers. The first measuring tube must be located 10m below the screw pump head. The connection between the measuring tubes above the dynamic liquid level is sealed with high temperature and high pressure sealing grease. Each measuring pipe is connected to the lower pump oil pipe or water lifting pipe through a plurality of ferrules; Repeat the above steps until the last measuring tube is lowered; the top measuring tube opening is higher than the wellhead, and the bottom measuring tube opening is plugged with a threaded plug.

9. A geothermal well water level monitoring system according to claim 1, characterized in that: The electric water level gauge probe is connected to a steel pipe, a lead block is added into the steel pipe to increase the counterweight, and a rubber sleeve is connected to the outer sleeve of the steel pipe.

10. A geothermal well water level monitoring system according to claim 1, characterized in that: The electric water level meter probe is connected to the ground instrument through a cable, and a high-strength thin steel cable is added inside the cable.

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