A recyclable wellbore thermal insulation simulation evaluation device and evaluation method
By designing a recyclable wellbore insulation simulation and evaluation device, the high-temperature and high-pressure environment downhole is simulated to evaluate the insulation effect of insulation materials. This solves the problem of difficulty in verifying the effect of insulation materials downhole in existing technologies and achieves efficient and reliable performance evaluation of insulation materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA UNIV OF PETROLEUM (EAST CHINA)
- Filing Date
- 2025-11-17
- Publication Date
- 2026-07-31
AI Technical Summary
Existing technologies make it difficult to directly verify the thermal insulation effect of wellbore insulation materials in extreme downhole environments, and field tests are costly and time-consuming, which limits the research and development and optimization of thermal insulation materials.
Design a recirculating wellbore insulation simulation and evaluation device to simulate the high temperature and high pressure environment downhole. The device evaluates the cooling effect of insulation materials by forming mud cake through drilling fluid filtration. The device includes a tank, a sealing cover, a simulated formation, a porous medium, drill pipe, and a heating jacket. It is equipped with pressure sensors, temperature sensors, and a computer control system to simulate the pressure, temperature, and shear environment during the drilling process.
It provides accurate evaluation of the thermal insulation effect of thermal insulation materials under laboratory conditions, reduces the risk of direct well testing, and provides high data authenticity and reliability, enabling the quantification of the actual thermal insulation performance of thermal insulation materials.
Smart Images
Figure CN121576047B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a recyclable wellbore insulation simulation evaluation device and method, belonging to the field of wellbore insulation simulation technology. Background Technology
[0002] With the accelerated progress of ultra-deep oil and gas exploration and development, downhole temperatures have generally exceeded 200°C. Intense heat exchange between the formation and the wellbore not only seriously threatens the stability of drilling fluid performance and wellbore safety, but also drastically reduces the effectiveness of traditional surface cooling methods. The emerging active wellbore insulation technology involves adding insulating materials to the drilling fluid, filtering them into mud cakes, and forming an insulating layer on the wellbore wall, thereby reducing the transfer of heat from the formation into the wellbore.
[0003] Wellbore insulation materials (such as porous ceramsite and hollow microspheres) have broad application prospects in suppressing heat transfer and reducing downhole temperatures due to their excellent thermal resistance properties. However, existing technologies mainly rely on laboratory-based thermophysical property (such as thermal conductivity) tests, lacking direct verification data on their actual insulation performance in extreme downhole environments such as high temperature and high pressure. Furthermore, in ultra-deep well drilling and completion operations, operational costs and construction cycles are strictly limited, making it difficult to conduct large-scale, long-term field tests. This restricts the accurate performance evaluation of insulation materials in wellbore insulation applications, and consequently limits the research and optimization of advanced insulation materials. Therefore, this invention is proposed. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a recyclable wellbore insulation simulation evaluation device and method, which can simulate the harsh environment of high temperature and high pressure in the wellbore and cause drilling fluid to be filtered out to form mud cake, thereby accurately evaluating the cooling effect of insulation materials under actual working conditions.
[0005] The technical solution of the present invention is as follows: A recyclable wellbore insulation simulation and evaluation device includes a tank, a sealing cover, a simulated formation, a porous medium, a drill pipe, and a heating jacket. The upper and lower parts of the tank are respectively equipped with sealing covers. The simulated formation and the porous medium are sequentially fitted on the inner wall of the tank. The drill pipe is located in the middle of the sealing cover. A through hole is provided at the bottom of the drill pipe. There is an annular space between the drill pipe and the porous medium. The heating jacket is provided on the outer wall of the tank.
[0006] According to a preferred embodiment of the present invention, the upper sealing cover of the tank body is provided with a pressure control port A and a drilling fluid inlet. The inner sides of the pressure control port A and the drilling fluid inlet are respectively connected to the annulus and the inside of the drill pipe. The lower sealing cover is provided with a pressure control port B. The inner side of the pressure control port B is connected to a simulated formation. The outer side of the drilling fluid inlet is connected to a storage tank via a centrifugal pump. The storage tank is connected to a cooler. The drilling fluid inlet, the outer side of the pressure control port B, and the storage tank are all connected to a pressure control system. The outer side of the pressure control port A is connected to the storage tank via an insulated pipeline. The storage tank, the inside of the drill pipe, and the annulus form a circulation pipeline.
[0007] According to a preferred embodiment of the present invention, the porous medium is a high-temperature and high-pressure filter screen with an average pore throat diameter of 2.7 μm, and the drilling fluid can form a mud cake on the surface of the porous medium.
[0008] According to a preferred embodiment of the present invention, a mud cake remover is provided on the sealing cap on the porous medium side. The mud cake remover includes an electric lifting linkage and a wire brush. Several electric lifting linkages are evenly distributed in the inner circumference of the sealing cap, and annular wire brushes are provided on the several electric lifting linkages. The linkages move up and down at a speed of 0.1-5 cm / min to remove mud cake from the surface of the porous medium.
[0009] According to a preferred embodiment of the present invention, a stirrer is provided on the sealing cap at the bottom of the annulus, with a stirring speed of 200-5000 rpm, to simulate the high-speed shear flow state of drilling fluid.
[0010] According to a preferred embodiment of the present invention, pressure sensors and temperature sensors are provided in the middle of the drill pipe, the annulus, the porous medium, and the tank to monitor pressure and temperature changes. The pressure control system, the electric lifting linkage, the pressure sensors, and the temperature sensors are all connected to a computer control system.
[0011] The evaluation method for the above-mentioned recirculating wellbore insulation simulation evaluation device and evaluation method includes the following steps: (1) Prepare water-based drilling fluid and inject it into the storage tank; (2) Drilling fluid is injected into the drill pipe through the drilling fluid inlet and then flows into the annulus through the through hole. The injection is stopped after the drill pipe and the annulus are completely filled with drilling fluid. (3) Connect the drilling fluid inlet to the pressure control system and apply pressure to the inside of the drill pipe. After the pressure is applied, the pressure is transmitted to the inside of the annulus through the bottom hole of the drill pipe. The pressure value of each part is read by the pressure sensor. (4) The pressure difference between the annulus and the simulated formation causes the drilling fluid to be lost in the porous medium and form a mud cake. At this time, the pressure inside the tank is unloaded through the pressure control port A. (5) Start the centrifugal pump to begin circulating the drilling fluid, while the pressure control system injects the same pressure into the storage tank and the drill pipe. (6) Start the heating jacket to heat the entire simulation evaluation device. The heat is transferred from the outside to the inside, gradually passing through the tank, simulated formation, porous medium, mud cake, and drill pipe, and finally reaching the inside of the drill pipe. At the same time, turn on the mud cake remover to simulate the high-speed shearing environment during the drilling process. Start the agitator to simulate the new formation that appears during the drilling process, so that the mud cake is redeposited into the formation under pressure. (7) Read the data from the temperature sensor, obtain the temperature values of each part, compare the final temperatures of the temperature sensors inside the annulus and inside the drill pipe, and obtain the heat insulation effect of the mud cake formed by the drilling fluid in the wellbore. The values of the simulated formation temperature sensor can be regarded as the formation temperature.
[0012] According to a preferred embodiment of the present invention, in step (1), the water-based drilling fluid preparation method is as follows: First, 96 parts of water and 4 parts of bentonite are dispersed at a high speed of 3000 rpm for 60 min, and then left to stand at room temperature for 24 h to obtain a base slurry; then 0-6 parts of hollow glass microsphere heat insulation material are added to the base slurry and dispersed at a high speed of 2000 rpm for 60 min to obtain a water-based drilling fluid with heat insulation material.
[0013] According to a preferred embodiment of the present invention, in step (3), the pressure difference between the annulus and the simulated formation is maintained within the range of 3 to 8 MPa, and the pressure is maintained for 10 to 60 minutes when the pressure reaches equilibrium.
[0014] According to a preferred embodiment of the present invention, in step (7), the heat insulation effect is calculated and evaluated by the following formula: T A - T B= T C in, T A To simulate formation temperature, T B The annular temperature is the temperature difference between the simulated formation temperature and the annular temperature. T C , T C The higher the value, the better the heat insulation effect of the mud cake.
[0015] By simulating drilling fluids with different compositions, the optimal component ratio was obtained.
[0016] The beneficial effects of this invention are as follows: 1. This invention constructs a highly integrated and controllable simulation and evaluation device for extreme environments in ultra-deep wells. By accurately establishing and maintaining high temperature, high pressure, and high speed shear environment inside the device, it solves the problem that thermal insulation materials cannot be effectively evaluated in the laboratory.
[0017] 2. This invention reproduces the extreme temperatures, pressures, differential pressures, high-speed shearing, new drilling processes, and complex heat transfer paths in downhole environments. It can place the thermal insulation material in the drilling fluid under thermodynamic conditions consistent with the downhole height, making the resulting mud cake structure and the adsorption distribution of the thermal insulation material closer to the actual situation. The obtained thermal insulation effect data has high authenticity and reliability, providing accurate laboratory basis for evaluating the performance of thermal insulation materials in actual ultra-deep well environments, and greatly reducing the risks and uncertainties of direct downhole testing.
[0018] 3. By comparing the heating rate and final temperature of the fluid inside the annulus and drill pipe, this invention can quantify the actual effect of the insulation material in preventing heat transfer into the wellbore. By comparing the changes in annulus temperature and drill pipe temperature, it can also analyze the main heat transfer path and the effectiveness of the insulation layer at different locations. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the mud cake remover structure of the present invention.
[0020] Among them, 1-sealing cap, 2-heating jacket, 3-tank body, 4-simulated formation, 5-porous medium, 6-mud cake remover, 7-agitator, 8-drill pipe, 9-through hole, 10-pressure control port B, 11-pressure sensor, 12-temperature sensor, 13-pressure control port A, 14-drilling fluid inlet, 15-insulated pipeline, 16-storage tank, 17-cooler, 18-computer control system, 19-pressure control system, 20-electric lifting linkage, 21-wire brush, 22-annulus. Detailed Implementation
[0021] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.
[0022] Example 1: like Figure 1-2 As shown, this embodiment provides a recyclable wellbore insulation simulation evaluation device, including a tank 3, a sealing cover 1, a simulated formation 4, a porous medium 5, a drill rod 8, and a heating sleeve 2. The upper and lower parts of the tank 3 are respectively provided with the sealing cover 1. The simulated formation 4 and the porous medium 5 are sequentially fitted on the inner wall of the tank 3. The drill rod 8 is provided in the middle of the sealing cover 1. The bottom of the drill rod 8 is provided with a through hole 9. There is an annular space 22 between the drill rod 8 and the porous medium 5. The heating sleeve 2 is provided on the outer wall of the tank 3.
[0023] The upper sealing cover of tank body 3 is provided with a pressure control port A13 and a drilling fluid inlet 14. The inner sides of pressure control port A13 and drilling fluid inlet 14 are connected to the annulus 22 and the inside of drill pipe 8, respectively. The lower sealing cover 1 is provided with a pressure control port B10. The inner side of pressure control port B10 is connected to a simulated formation 4. The outer side of drilling fluid inlet 14 is connected to a storage tank 16 through a centrifugal pump. The storage tank 16 is connected to a cooler 17. The drilling fluid inlet 14, the outer side of pressure control port B10, and the storage tank 16 are all connected to a pressure control system 19. The outer side of pressure control port A13 is connected to the storage tank 16 through an insulated pipeline 15. The storage tank 16, the inside of drill pipe 8, and the annulus 22 form a circulation pipeline.
[0024] The porous medium 5 uses a high-temperature and high-pressure filter screen with an average pore throat diameter of 2.7 μm, and the drilling fluid can form a mud cake on the surface of the porous medium.
[0025] A mud cake remover 6 is provided on the sealing cover on one side of the porous medium 5. The mud cake remover 6 includes an electric lifting linkage 20 and a wire brush 21. Several electric lifting linkages 20 are evenly distributed in the inner circumference of the sealing cover 1. Several electric lifting linkages 20 are provided with annular wire brushes 21, which lift and lower at a speed of 0.1-5cm / min to remove mud cake from the surface of the porous medium.
[0026] An agitator 7 is installed on the sealing cap at the bottom of the annulus 22, with a stirring speed of 200-5000 rpm, to simulate the high-speed shear flow of drilling fluid.
[0027] Pressure sensors 11 and temperature sensors 12 are installed in the middle of the drill pipe 8, the annulus 22, the porous medium 5, and the tank 3 to monitor pressure and temperature changes. The pressure control system 19, the electric lifting linkage 20, and the pressure sensor 11 and temperature sensor 12 are all connected to the computer control system 18.
[0028] The evaluation method for the above-mentioned recirculating wellbore insulation simulation evaluation device and evaluation method includes the following steps: (1) Prepare water-based drilling fluid and inject it into storage tank 16. The preparation method of water-based drilling fluid is as follows: First, disperse 96 parts of water and 4 parts of bentonite under high-speed stirring at 3000 rpm for 60 min, and then let it stand at room temperature for 24 h to obtain the base slurry; then add 6 parts of hollow glass microsphere heat insulation material to the base slurry and disperse it under high-speed stirring at 2000 rpm for 60 min to obtain water-based drilling fluid with heat insulation material.
[0029] (2) Drilling fluid is injected into the drill pipe 8 through drilling fluid inlet 14 and then flows into the annulus 22 through through hole 9. The injection is stopped after the drill pipe 8 and the annulus 22 are completely filled with drilling fluid. (3) Connect the drilling fluid inlet 14 to the pressure control system 19 and apply pressure to the inside of the drill pipe 8. After the pressure is applied, the pressure is transmitted to the inside of the annulus 22 through the bottom hole of the drill pipe 8. Read the pressure values of each part through the pressure sensor 11 and keep the pressure difference between the inside of the annulus and the simulated formation within the range of 3~8MPa. When the pressure reaches equilibrium, keep the pressure for 10~60min. (4) The pressure difference between the annulus 22 and the simulated formation 4 causes the drilling fluid to be lost on the porous medium 5 and form a mud cake. At this time, the pressure inside the tank 3 is unloaded through the pressure control port A13. (5) Start the centrifugal pump to begin circulating the drilling fluid, while the pressure control system 19 injects the same pressure into the storage tank 16 and the drill pipe 8. (6) Start the heating jacket 2 to heat the entire simulation evaluation device. The heating temperature is 200℃ and the heating time is 3h. The heat is transferred from the outside to the inside, gradually passing through the tank 3, the simulated formation 4, the porous medium 5, the mud cake, and the drill pipe 8, and finally reaching the inside of the drill pipe 8. At the same time, turn on the mud cake remover 6 to simulate the high-speed shearing environment during the drilling process. Start the agitator 7 to simulate the new formation that appears during the drilling process, so that the mud cake is redeposited into the formation under pressure. (7) Read the data of temperature sensor 12, obtain the temperature values of each part, compare the final temperature of the temperature sensor inside the annulus and inside the drill pipe, and obtain the heat insulation effect of the mud cake formed by the drilling fluid in the wellbore. The value of the simulated formation temperature sensor can be regarded as the formation temperature. The insulation effect is calculated and evaluated using the following formula: T A - T B= T C in, T A To simulate formation temperature, T B The annular temperature is the temperature difference between the simulated formation temperature and the annular temperature. T C , T C The higher the value, the better the heat insulation effect of the mud cake.
[0030] In this embodiment, the simulated formation temperature is 192°C, the annular temperature is 178°C, and the temperature difference is 14°C.
[0031] Example 2: An evaluation method for a recyclable wellbore insulation simulation evaluation device and evaluation method, the steps are as described in Example 1, the difference being that in step (1), the water-based drilling fluid preparation method is as follows: firstly, 96 parts of water and 4 parts of bentonite are dispersed under high-speed stirring at 3000 rpm for 60 min, and then left to stand at room temperature for 24 h to obtain the base slurry. The base slurry is used as the drilling fluid for simulation, and the simulated formation temperature is 192℃, the annular temperature is 188℃, and the temperature difference is 4℃.
[0032] Example 3: An evaluation method for a recyclable wellbore insulation simulation evaluation device and evaluation method, the steps are as described in Example 1, the difference being that in step (1), the water-based drilling fluid preparation method is as follows: first, 96 parts of water and 4 parts of bentonite are dispersed at a high speed of 3000 rpm for 60 min, and then left to stand at room temperature for 24 h to obtain the base slurry. 3 parts of hollow glass microsphere insulation material are added to the base slurry and dispersed at a high speed of 2000 rpm for 60 min to obtain the water-based drilling fluid with insulation material.
[0033] In this embodiment, the simulated formation temperature is 192°C, the annular temperature is 183°C, and the temperature difference is 9°C.
[0034] Example 4: An evaluation method for a circulating wellbore insulation simulation evaluation device and evaluation method, the steps are as described in Example 1, except that in step (6), the heating temperature is 240℃.
[0035] In this embodiment, the simulated formation temperature is 236°C, the annular temperature is 234°C, and the temperature difference is 2°C.
[0036] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. An evaluation method for a recyclable wellbore insulation simulation evaluation device, characterized in that, The device includes a tank, a sealing cover, a simulated formation, a porous medium, a drill rod, and a heating jacket. The upper and lower parts of the tank are respectively equipped with sealing covers. The simulated formation and the porous medium are sequentially fitted on the inner wall of the tank. The drill rod is located in the middle of the sealing cover. A through hole is provided at the bottom of the drill rod. There is an annular space between the drill rod and the porous medium. The heating jacket is provided on the outer wall of the tank. The upper sealing cover of the tank is equipped with a pressure control port A and a drilling fluid inlet. The inner sides of the pressure control port A and the drilling fluid inlet are connected to the annulus and the inside of the drill pipe, respectively. The lower sealing cover is equipped with a pressure control port B. The inner side of the pressure control port B is connected to a simulated formation. The outer side of the drilling fluid inlet is connected to a storage tank via a centrifugal pump. The storage tank is connected to a cooler. The drilling fluid inlet, the outer side of the pressure control port B, and the storage tank are all connected to a pressure control system. The outer side of the pressure control port A is connected to the storage tank. The storage tank, the inside of the drill pipe, and the annulus form a circulation pipeline. A cake remover is installed on the sealing cover on the porous medium side. The cake remover includes an electric lifting rod and a wire brush. Several electric lifting rods are evenly distributed on the inner circumference of the sealing cover, and annular wire brushes are installed on several electric lifting rods. An agitator is installed on the sealing cap at the bottom of the annulus. Pressure and temperature sensors are installed in the middle of the drill pipe, the annulus, the porous medium, and the tank to monitor pressure and temperature changes. The pressure control system, the electric lifting linkage, the pressure sensors, and the temperature sensors are all connected to a computer control system. The evaluation method for the above-mentioned recyclable wellbore insulation simulation evaluation device includes the following steps: (1) Prepare water-based drilling fluid and inject it into the storage tank; (2) Drilling fluid is injected into the drill pipe through the drilling fluid inlet and then flows into the annulus through the through hole. The injection is stopped after the drill pipe and the annulus are completely filled with drilling fluid. (3) Connect the drilling fluid inlet to the pressure control system and apply pressure to the inside of the drill pipe. After the pressure is applied, the pressure is transmitted to the inside of the annulus through the bottom hole of the drill pipe and the pressure value is read by the pressure sensor. (4) The pressure difference between the annulus and the simulated formation causes the drilling fluid to be lost in the porous medium and form a mud cake. At this time, the pressure inside the tank is unloaded through the pressure control port A. (5) Start the centrifugal pump to begin circulating the drilling fluid, while the pressure control system injects the same pressure into the storage tank and the drill pipe. (6) Start the heating jacket to heat the entire simulation evaluation device. The heat is transferred from the outside to the inside, gradually passing through the tank, simulated formation, porous medium, mud cake, and drill pipe, and finally reaching the inside of the drill pipe. At the same time, turn on the mud cake remover to simulate the high-speed shearing environment during the drilling process. Start the agitator to simulate the new formation that appears during the drilling process, so that the mud cake is redeposited into the formation under pressure. (7) Read the data from the temperature sensor, compare the final temperatures of the temperature sensors inside the annulus and inside the drill pipe, and obtain the heat insulation effect of the mud cake formed by the drilling fluid in the wellbore. The value of the simulated formation temperature sensor is considered as the formation temperature.
2. The evaluation method for the recirculating wellbore insulation simulation evaluation device as described in claim 1, characterized in that, The porous medium uses a filter screen.
3. The evaluation method for the recirculating wellbore insulation simulation evaluation device as described in claim 1, characterized in that, In step (1), the water-based drilling fluid is prepared as follows: First, 96 parts of water and 4 parts of bentonite are dispersed at 3000 rpm for 60 min under high-speed stirring, and then left to stand at room temperature for 24 h to obtain the base slurry; then, 3 or 6 parts of hollow glass microsphere heat insulation material are added to the base slurry and dispersed at 2000 rpm for 60 min under high-speed stirring to obtain the water-based drilling fluid with heat insulation material.
4. The method of evaluating the recyclable wellbore thermal insulation simulation evaluation device of claim 1, wherein, In step (3), the pressure difference between the annulus and the simulated formation is maintained in the range of 3~8MPa. When the pressure reaches equilibrium, the pressure is maintained for 10~60min.
5. The method of evaluating a recyclable wellbore heat protection simulation evaluation device of claim 1, wherein, In step (7), the insulation effect is calculated and evaluated using the following formula: T A - T B= T C in, T A To simulate formation temperature, T B The annular temperature is the temperature difference between the simulated formation temperature and the annular temperature. T C , T C The higher the value, the better the heat insulation effect of the mud cake.