An evaluation method and system for heat insulation performance of insulated oil pipes under different loads

Abstract

The application discloses a heat insulation performance evaluation method and system for heat preservation oil pipes under different loads, estimates the load borne by the heat preservation oil pipe under different loading modes at different well depths, simultaneously records the temperature change rule of the heat preservation oil pipe under different depths, different loading modes and the same heat preservation time based on full-size physical simulation test loading, and finally detects the temperature difference value between the initial temperature and the end temperature of the oil pipe based on the temperature change rule, compares the temperature difference value with the expected set temperature difference value respectively, determines the depth of the maximum depth of the heat preservation oil pipe based on the comparison result, and finds the position of the heat insulation failure, thereby providing technical support for the selection of the heat insulation oil pipe on site. The application solves the problems that the heat preservation pipe depth is uncertain and the heat insulation effect cannot achieve the expected purpose frequently.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of drilling, and relates to a heat preservation oil pipe heat insulation performance evaluation method and system under different loads. BACKGROUND

[0002] With the development of oil and gas development technology in China, the development of many difficult-to-use energy and new energy has also been put on the agenda, such as super heavy oil, deep light oil and natural gas, underground coal gasification, geothermal energy and hot dry rock, etc. However, some new problems have also emerged. For example, traditional steam injection is used to improve heavy oil recovery, but the injection process of steam from the ground to the reservoir will cause a large amount of heat loss and reduce the production capacity; deep light oil has a high wax content, and the temperature decreases from the bottom of the well to the wellhead during the mining process, resulting in wax blocking; high-pressure gas wells also have hydrate formation due to temperature and pressure fluctuations, causing wellhead manifold plugging; especially in the mining process of new clean energy "geothermal energy", heat preservation is one of the main problems. These oil and gas mining engineering problems are related to the heat loss of the heat fluid, so experts and scholars propose to use heat preservation oil pipes to reduce the heat loss of the high-temperature fluid underground. At present, the commonly used heat insulation oil pipes on the market are pre-stressed vacuum heat insulation oil pipes and externally coated heat insulation oil pipes, but the heat insulation oil pipe itself needs to withstand certain tensile, internal pressure, external extrusion and other loads. There are few reports on the influence of different loads on the heat insulation stability of the heat insulation oil pipe. Therefore, it is particularly important to determine the change rule of the heat insulation performance of the oil pipe under the action of different loads by means of physical simulation test, form an evaluation method for the heat insulation performance of the heat insulation oil pipe under the action of different loads, and provide technical support for efficient mining of underground coal gasification, geothermal energy and super heavy oil. SUMMARY

[0003] The application aims to solve the problem that the prior art only considers the apparent thermal conductivity of the heat preservation pipe under static conditions, without considering the influence of actual mechanical working conditions on the heat insulation performance of the heat preservation pipe, resulting in uncertain depth of the heat preservation pipe, frequent failure of the heat insulation effect to achieve the expected purpose, and great waste of economic investment. The application provides a heat preservation oil pipe heat insulation performance evaluation method and system under different loads, determines the heat insulation performance of the heat preservation oil pipe based on a full-size test method, simulates the field working conditions, performs complex physical mechanical tests such as tension, internal pressure, external extrusion and bending on the heat insulation oil pipe, forms the influence rule of different loads on the heat insulation performance of the heat preservation oil pipe, and determines the depth of the heat insulation oil pipe, thereby providing technical support for the selection of the heat insulation oil pipe on site.

[0004] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0005] A heat preservation oil pipe heat insulation performance evaluation method under different loads, comprising the following steps:

[0006] S1: calculating the load of the heat preservation oil pipe under different loading modes at different well depths;

[0007] S2: Simulate the working condition test based on the obtained load data, and load the heat preservation oil pipe;

[0008] S3: Record the temperature change rule of the heat preservation oil pipe at different depths, different loading modes and the same heat preservation time;

[0009] S4: Detect the temperature difference value of the initial temperature and the end temperature of the oil pipe based on the temperature change rule, compare the temperature difference value with the expected set temperature difference value respectively, determine the depth of the maximum depth of the heat preservation oil pipe based on the comparison result, and find the position of the heat insulation failure.

[0010] Further improvement of the method is that:

[0011] The calculation method of S1 is:

[0012]

[0013]

[0014]

[0015] The different loading modes in S2 include bending, extrusion and stretching + internal pressure;

[0016] The different depths include 500m, 1000m, 1500m and 2000m.

[0017] The method for judging the position of heat insulation failure is:

[0018] The expected set temperature difference value is used as the judgment standard:

[0019] When the actual measured temperature difference value is lower than the expected set temperature difference value, it indicates that the area is a safe area;

[0020] When the actual measured temperature difference value is higher than the expected set temperature difference value, it indicates that the area is a failure area;

[0021] The position with the highest temperature is the position of heat insulation failure.

[0022] The method for judging the maximum depth of the heat preservation oil pipe is:

[0023] When the actual measured temperature difference value is equal to the expected set temperature difference value, the corresponding well depth value is recorded, and the minimum well depth value is the maximum well depth value of the heat preservation oil pipe.

[0024] A heat preservation oil pipe heat insulation performance evaluation system under different loads, comprising a load estimation module, a full-size physical simulation loading test module, a temperature recording module and a heat insulation failure judgment module;

[0025] A load estimation module is configured to estimate the strength value of the heat-insulated tubing under different loading modes at different well depths;

[0026] A full-size physical simulation loading test module is configured to perform simulation working condition tests based on the obtained load data and load the heat-insulated tubing;

[0027] A temperature recording module is configured to record the change rule of the heat-insulated tubing at different depths, different loading modes, different loads and the same heat-insulation time;

[0028] A heat-insulation failure judgment module is configured to detect the temperature difference value of the initial temperature and the end temperature of the tubing based on the temperature change rule, compare the temperature difference value with the expected set temperature difference value respectively, determine the maximum depth of the heat-insulated tubing based on the comparison result, and find the position of the heat-insulation failure.

[0029] A heat-insulated tubing loading device based on full-size physical simulation tests, comprising a heat-insulated tubing main body, a heat-insulation layer, a thermocouple, a heating medium and a heat-insulated tubing clamp;

[0030] The heat-insulated tubing main body is arranged on the inner side of the heat-insulation layer, the thermocouple and the heating medium are arranged in the interior of the heat-insulated tubing main body, and the heat-insulated tubing clamp is arranged at both ends of the heat-insulated tubing main body.

[0031] A terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of claims 1-5 when executing the computer program.

[0032] A computer readable storage medium storing a computer program, wherein the computer program is executable by a processor to implement the steps of the method according to any one of claims 1-5.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] The present application simulates and calculates the load value of the heat-insulated tubing under different loading modes from the simulation of actual working conditions, compares the actually measured temperature difference values at the beginning and the end with the expected set temperature difference values respectively, determines the maximum depth of the heat-insulated tubing, and determines the heat-insulation performance under different loading modes, and also determines the change rule of the heat-insulation performance of the heat-insulated tubing under different loads, establishes a heat-insulated tubing depth judgment method under different loads, provides technical support for the fine selection of heat-insulated tubing on site, and reduces the input cost. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0036] Figure 1 The schematic diagram for evaluating the heat insulation performance of the heat preservation oil pipe under no external load of the present application;

[0037] Figure 2 The schematic diagram for evaluating the heat insulation performance of the heat preservation oil pipe under external load of the present application;

[0038] Figure 3 The schematic diagram for evaluating the heat insulation performance of the heat preservation oil pipe under tensile + internal pressure load of the present application;

[0039] Figure 4 The schematic diagram for evaluating the heat insulation performance of the heat preservation oil pipe under bending load of the present application.

[0040] Figure 5 The diagram for determining the depth of the heat insulation oil pipe under different load conditions.

[0041] Wherein, 1 is the main body of the heat preservation oil pipe; 2 is the heat preservation layer; 3 is the thermocouple; 4 is the heating medium; 5 is the heat preservation oil pipe clamp. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0044] It should be noted that: similar labels and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0045] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, or the orientation or position relationship when the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", etc. are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0046] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0047] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, if the terms "arrangement", "installation", "connection", "connection" appear, they should be understood in a broad sense. For example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0048] The present application will be described in further detail below in conjunction with the drawings:

[0049] Referring to Figure 1 The embodiments of the present application disclose a method for evaluating the heat insulation performance of heat preservation oil pipes under different loads,

[0050] (1) The field working condition parameters of the heat preservation oil pipe are used, as shown in Table 1:

[0051] Table 1 Field working condition parameter table

[0052]

[0053] (2) According to the research working condition parameters and the Lame formula, the strength values of the heat preservation oil pipe under different well depths h, such as external extrusion Pextrusion, tension Flax, and internal pressure Pin, are estimated:

[0054] characterized in that the calculation method of S1 is:

[0055]

[0056]

[0057]

[0058] (3) Different insulation oil pipes in different stress conditions of the thermal performance evaluation test;

[0059] 1. Test method

[0060] Referring to Figure 1 , the heating oil or water of T0 temperature is passed into the insulation oil pipe, and after the two ends are blocked, the change curve of the oil temperature in the insulation oil pipe with time is collected, and the test end temperature T1 is recorded.

[0061] Referring to Figure 2 , the heating oil or water of TC0 temperature is passed into the insulation oil pipe, and after the two ends are blocked, the sample is subjected to external extrusion test, and the specific loading program is referred to Table 2, and the change of the oil temperature in the pipe with time is collected, and the test end temperature TC1 is recorded.

[0062] Referring to Figure 3 , the heating oil or water of TL0 temperature is passed into the insulation oil pipe, and after the two ends are blocked, the sample is loaded with tensile and internal pressure load, and the specific loading program is referred to Table 2, and the change of the oil temperature in the pipe with time is collected, and the test end temperature TL1 is recorded.

[0063] Referring to Figure 4 , the heating oil or water of TB0 temperature is passed into the insulation oil pipe, and after the two ends are blocked, the sample is subjected to bending deformation, and the specific deformation program is referred to Table 2, and the change of the oil temperature in the pipe with time is collected, and the test end temperature TB1 is recorded.

[0064] 2. Loading mode and loading program

[0065] According to the test program in Table 2, the mechanical loading test of the simulated full-size insulation oil pipe under different load modes, different depth loads and different holding time is carried out.

[0066] Table 2 Mechanical loading program of simulated insulation oil pipe at different depths

[0067]

[0068] Note: 1) In the table P 1, P 2, P 3, P 4 respectively represent different loads corresponding to the insulation oil pipe at different depths (such as h=500m, 1000m, 1500m, 2000m), and the specific values are calculated according to the formulas 1-3, and the test can select different depths h and different step numbers according to the actual working conditions;

[0069] 2) In the table, △t represents the holding time at each load level, which can be the same or different, and is recommended to be not less than 25min.

[0070] The loading depth in the embodiment of the application can be selected according to experimental requirements to perform experiments.

[0071] 3. Calculate and draw the depth judgment graph of the heat preservation tube

[0072] According to the above experimental results, the temperature difference Δt before and after the experiment under different depths and different loading modes is calculated, and the temperature difference-depth curve is fitted by using the temperature difference values measured at different depths under the same loading mode (as shown in Figure 5 According to the criterion of the maximum design temperature difference ΔTmax, the II zone below ΔTmax (i.e., the measured temperature difference is less than ΔTmax) is a safety zone, and the I zone above ΔTmax (i.e., the measured temperature difference is greater than ΔTmax) is a failure zone, and the intersection point of the temperature difference curve under various loads and ΔTmax is the minimum well depth corresponding to the maximum running depth of the heat preservation oil tube.

[0073] 4. Find the leakage point of the heat preservation oil tube

[0074] The infrared thermal imager is used to detect the leakage point, determine the point at which the heat insulation of the heat preservation oil tube fails first, and make a mark.

[0075] The embodiment of the application discloses a test evaluation process:

[0076] The heat preservation performance evaluation method of the oil tube is illustrated by taking the P110 steel grade Φ88.9mm heat preservation oil tube as an example, and the maximum temperature difference ΔTmax is designed to be 15℃.

[0077] The working condition parameters of an oil well in an oilfield are shown in Table 3:

[0078]

[0079] Referring to Figure 5 , the temperature difference-depth graph is drawn according to the heat insulation performance evaluation method of the heat preservation oil tube under different stress conditions at different depths, the maximum depth of the oil tube under different loads is judged, and the results are as follows:

[0080] Under the bending load, the temperature difference increases with the increase of the dogleg degree, but under the condition of the maximum dogleg degree 15° / 30m, the measured temperature difference value is located in the II zone safety zone, and it can be seen that under the maximum bending load, the heat insulation performance of the heat preservation oil tube still meets the requirements;

[0081] Under the tensile + internal pressure load, the temperature difference increases with the decrease of the well depth value, but it can be seen from the temperature difference curve drawn by the experiment that even the temperature difference at the wellhead is in the II zone safety zone, and it can be seen that the tensile + internal pressure load has little effect on the heat insulation performance of the heat preservation oil tube under this well condition.

[0082] Under the external extrusion load, the temperature difference increases with the increase of the well depth, until the well depth is 1667m, the temperature difference intersects with the design temperature difference Tmax, and it is judged that the maximum depth of the heat preservation oil pipe is 1667m.

[0083] The infrared thermal imager is used for detecting the outside of the heat preservation pipe, and it is found that the heat insulation failure occurs at the center position of the oil pipe, and it is judged that the extrusion rupture causes the heat insulation failure.

[0084] The embodiment of the present application discloses a heat insulation performance evaluation system of heat preservation oil pipe under different loads, a load estimation module, a full-size physical simulation loading test module, a temperature recording module and a heat insulation failure judgment module.

[0085] The load estimation module is used for estimating the strength value of the heat preservation oil pipe under different loading modes at different well depths.

[0086] The full-size physical simulation loading test module is used for simulating the working condition test based on the obtained load data, and loading the heat preservation oil pipe.

[0087] The temperature recording module is used for recording the change rule of the heat preservation oil pipe at different depths, different loading modes and the same heat preservation time.

[0088] The heat insulation failure judgment module is used for detecting the temperature difference value of the initial temperature and the end temperature of the oil pipe based on the temperature change rule, comparing the temperature difference value with the expected set temperature difference value respectively, judging and finding the position of the heat insulation failure based on the comparison result, and judging the depth of the maximum depth of the heat preservation oil pipe.

[0089] An embodiment of the present application provides a schematic diagram of a terminal device. The terminal device of the embodiment comprises a processor, a memory, and a computer program stored in the memory and executable on the processor. The processor implements the steps in each of the method embodiments when executing the computer program. Alternatively, the processor implements the functions of each module / unit in each of the device embodiments when executing the computer program.

[0090] The computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present application.

[0091] The terminal device can be a desktop computer, a notebook, a palm computer and a cloud server, and the like. The terminal device can include, but is not limited to, a processor and a memory.

[0092] The processor can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc.

[0093] The memory can be used to store the computer program and / or modules, and the processor realizes various functions of the terminal device by running or executing the computer program and / or modules stored in the memory, and calling the data stored in the memory.

[0094] The modules / units integrated in the terminal device, if realized in the form of software function units and sold or used as independent products, can be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. When the processor executes the computer program, the steps of the above-mentioned various method embodiments can be realized. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content included in the computer readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice. For example, according to some legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.

Claims

1. A method for evaluating the heat insulation performance of insulated tubing under different loads, characterized in that, It comprises the following steps: S1: calculating the load of the heat preservation oil pipe under different loading modes at different well depths; S2: performing simulation working condition test based on the obtained load data to load the heat preservation oil pipe; S3: recording the temperature change rule of the heat preservation oil pipe under different depths, different loading modes and the same heat preservation time; S4: detecting the temperature difference value of the initial temperature and the end temperature of the oil pipe based on the temperature change rule, comparing the temperature difference value with the expected set temperature difference value respectively, determining the depth of the maximum depth of the heat preservation oil pipe based on the comparison result, and finding the position of the heat insulation failure. The calculation method of S1 is: D represents the outer diameter of the tubing; H represents the well depth; P 挤 F represents the external extrusion force on the insulated tubing; P 环max P represents the maximum annular protection fluid pressure; ρ 环 D represents the annular protection fluid density; g G represents the acceleration of gravity; h H represents the current well depth; F 拉 F represents the tensile force on the insulated tubing; P 梯度 G represents the pressure gradient; P 油 max P represents the maximum oil pressure; P 地 P represents the formation pressure; P 内 P represents the tubing internal pressure at different well depths.

2. The method for evaluating the heat insulation performance of insulated tubing under different loads according to claim 1, characterized in that, The different loading modes in S3 include bending and pressing, external extrusion and stretching + internal pressure. The different depths include 500m, 1000m, 1500m and 2000m.

3. The method for evaluating the heat insulation performance of insulated tubing under different loads according to claim 1, characterized in that, The method for judging the position of heat insulation failure is: Taking the expected set temperature difference value as the judgment standard: When the actually measured temperature difference value is lower than the expected set temperature difference value, it indicates that the area is a safe area; When the actually measured temperature difference value is higher than the expected set temperature difference value, it indicates that the area is a failure area; Finding the position with the highest temperature is the position of heat insulation failure.

4. The method for evaluating the heat insulation performance of insulated tubing under different loads according to claim 3, characterized in that, The method for determining the depth of the maximum depth of the heat preservation oil pipe based on the comparison result is: Recording the well depth value corresponding to the actual measured temperature difference value and the expected set temperature difference value at the same time, wherein the smallest well depth value is the maximum well depth value of the heat preservation oil pipe.

5. An evaluation system for evaluating the heat insulation performance of the tubing under different loads based on the method of claim 1, characterized in that, It comprises a load estimation module, a full-size physical simulation loading test module, a temperature recording module and a heat insulation failure judgment module. The load estimation module is used to estimate the strength value of the heat preservation oil pipe under different loading modes at different well depths; The full-size physical simulation loading test module is used to perform simulation working condition test based on the obtained load data to load the heat preservation oil pipe; The temperature recording module is used to record the change rule of the heat preservation oil pipe under different depths, different loading modes, different loads and the same heat preservation time; The heat insulation failure judgment module is used to detect the temperature difference value of the initial temperature and the end temperature of the oil pipe based on the temperature change rule, compare the temperature difference value with the expected set temperature difference value respectively, determine the depth of the maximum depth of the heat preservation oil pipe based on the comparison result, and find the position of the heat insulation failure.

6. An insulated tubing loading device based on full-scale physical simulation testing based on the method of claim 1, characterized in that, It comprises a heat preservation oil pipe body (1), a heat preservation layer (2), a thermocouple (3), a heating medium (4) and a heat preservation oil pipe clamp (5). The heat preservation oil pipe body (1) is arranged on the inner side of the heat preservation layer (2), the thermocouple (3) and the heating medium (4) are arranged in the heat preservation oil pipe body (1), and the heat preservation oil pipe clamp (5) is arranged at both ends of the heat preservation oil pipe body (1).

7. A terminal device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the steps of the method according to any one of claims 1-4.

8. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 7. The computer program is executed by the processor to realize the steps of the method according to any one of claims 1-4.

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