Device and method for testing performance of high-temperature-resistant drilling fluid

Abstract

The invention discloses a high-temperature-resistant drilling fluid performance testing device and testing method, and belongs to the technical field of material performance analysis. The testing device comprises a slurry cup, a piston assembly and an air source device, and the piston assembly comprises a piston body, two groups of sealing rings located on the side wall of the piston body and arranged at intervals in the axial direction of the piston body, and a drainage channel. An opening in one end of the drainage channel is located between the two sealing rings, an opening in the other end of the drainage channel communicates with a drainage discharge pipe at the bottom of the slurry cup through a hose, and the gas source equipment is used for supplementing gas to the bottom of the slurry cup and pushing the piston assembly to move upwards. According to the invention, the piston in the slurry cup is driven by gas to move, the residual displacement medium in the slurry cup is gas when displacement is completed, the next round of experiment can be started without recovery and direct discharge, the experiment time is saved, and the drainage channel is arranged between the sealing rings of the piston, so that the leaked fluid is led out of the slurry cup, and the leakage is avoided. The gas is prevented from entering the drilling fluid, so that the accuracy of test data is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of material property analysis, and specifically to a high-temperature resistant drilling fluid performance testing device and testing method for analyzing the filtration performance of drilling fluid. Background Art

[0002] The filtration performance is an important parameter in the performance evaluation of drilling fluid. Currently, the main equipment for testing this performance is a static filter press, which evaluates the filtration performance of drilling fluid by measuring the time or rate at which the drilling fluid passes through a filter medium (such as filter paper) under a specific pressure difference.

[0003] Existing static filter presses mainly include components such as a graduated cylinder, a vertically arranged mud cup, and a constant temperature jacket for heating the mud cup. The mud cup is a pressure vessel with openings at both ends for containing drilling fluid, and the graduated cylinder is used to measure the drilling fluid passing through the filter medium. In early static filter presses, the filter medium was set at the bottom of the mud cup. During use, gas was injected into the mud cup through the top opening of the mud cup to increase the drilling fluid pressure and drive it through the filter medium. However, the drilling fluid often contains solid particle impurities, which tend to settle and accumulate on the filter medium under static conditions, affecting the formation of the filter cake on the surface of the filter medium, resulting in a large deviation in the filtration loss. For this reason, later, in some devices, the filter medium was set at the top outlet of the mud cup, and a piston was set in the mud cup. A hydraulic pump was used to inject silicone oil into the mud cup to drive the piston to move upward, thereby driving the drilling fluid to pass through the filter medium from bottom to top. This avoided the problem of solid particle deposition affecting the formation of the filter cake. However, when gas pressurization filtration was used in the early stage, after the displacement was completed, the mud cup was basically filled with gas, and a new round of experiments could be started directly by discharging the gas after one round of experiments. When silicone oil displacement was used, the silicone oil, as the power fluid, needed to be recovered. However, when testing at high temperatures, the temperature of the silicone oil was relatively high and needed to be cooled, which significantly increased the experimental time. In addition, during the experiment, the drilling fluid and the silicone oil were mainly separated by the piston. Since there was a gap between the piston and the mud cup, this separation was not absolutely reliable. Especially during repeated heating and cooling during the experiment, the piston aged relatively quickly and often leaked, causing the silicone oil to mix into the drilling fluid. Since the density of the silicone oil is generally lower than that of the drilling fluid, it will float upward after entering the drilling fluid and preferentially pass through the filter medium, ultimately resulting in a large deviation in the filtration loss. Summary of the Invention

[0004] To solve at least one of the above problems, the present invention provides a high-temperature resistant drilling fluid performance testing device, which arranges a filtering medium on the upper end face of the mud cup to avoid the deposition of solid particles from affecting the formation of the filter cake, uses gas to drive the piston in the mud cup to move, and sets a drainage channel between the sealing rings of the piston to lead the leaked fluid outside the mud cup, thereby preventing gas from entering the drilling fluid and affecting the fluid loss of the drilling fluid. When the displacement is completed, there is still residual gas in the mud cup, and the next round of experiment can be started directly by discharging it, saving experimental time.

[0005] To achieve the above object, the specific solution of the present invention is as follows: A high-temperature resistant drilling fluid performance testing device, comprising: A mud cup, which is vertically arranged and has a filtering medium provided on the inner wall of its top; A piston assembly, which is slidably and sealingly connected to the inner wall of the mud cup and can slide along the axial direction of the mud cup. The piston assembly divides the interior of the mud cup into a sample chamber and a power chamber, and the sample chamber is located above the power chamber. The piston assembly includes: A piston body; Two groups of sealing rings, which are arranged at intervals along the axial direction of the piston body. Each group of sealing rings is fixed to the side wall of the piston body and abuts against the inner wall of the mud cup; A drainage channel, which is arranged in the piston body. One end opening of the drainage channel is located on the side wall of the piston body and between the two groups of sealing rings, and the other end opening is communicated with a drainage discharge pipe at the bottom of the mud cup through a hose. A valve is provided on the drainage discharge pipe; Two pressure gauges, which are respectively used to measure the pressures of the sample chamber and the drainage channel; A gas source device, which is used to supplement gas to the power chamber and the drainage channel; A graduated cylinder, which is used to receive the drilling fluid passing through the filtering medium; A constant temperature jacket, which is used to heat the mud cup.

[0006] As a specific embodiment of the present invention, it further includes a partition sealing ring located between the two groups of sealing rings and arranged at intervals therewith. The partition sealing ring is fixed to the side wall of the piston body and abuts against the inner wall of the mud cup; the two groups of sealing rings are respectively an upper sealing ring and a lower sealing ring located below the upper sealing ring, and a water-swellable rubber ring is arranged between the lower sealing ring and the partition sealing ring; The drainage channel includes: A first branch pipe, one end opening of which is located on the side wall of the piston body and between the upper sealing ring and the partition sealing ring; A second branch pipe, one end opening of which is located on the side wall of the piston body and between the water-swellable rubber ring and the partition sealing ring; A vertically arranged main pipe, the other ends of the first branch pipe and the second branch pipe are respectively communicated with the main pipe; The gas in the power chamber is a gas containing water vapor.

[0007] It further includes a partition sealing ring fixed to the side wall of the piston body and abutting against the inner wall of the mud cup. The partition sealing ring is arranged at intervals with the two groups of sealing rings. The two groups of sealing rings are respectively an upper sealing ring and a lower sealing ring located below the upper sealing ring. A water-swellable rubber ring is arranged between the lower sealing ring and the partition sealing ring. The drainage channel includes: A first branch pipe, one end of which is open on the side wall of the piston body and located between the upper sealing ring and the partition sealing ring; A second branch pipe, one end of which is open on the side wall of the piston body and located between the water-swellable rubber ring and the partition sealing ring; A main pipe arranged vertically. The other ends of the first branch pipe and the second branch pipe are respectively communicated with the main pipe; The gas in the power chamber is a gas containing water vapor.

[0008] Furthermore, the main pipe is a stepped hole. The connection port of the second branch pipe and the main pipe is located on the step surface of the stepped hole; a ring-shaped floating body is arranged in the stepped hole. The ring-shaped floating body can float on the surface of the drilling fluid and the hollow part is greater than or equal to the size of the small hole in the stepped hole, so that when the upper end surface of the ring-shaped floating body abuts against the step surface of the stepped hole, the connection port of the second branch pipe and the main pipe can be blocked.

[0009] Furthermore, a mixing chamber is arranged between the gas source device and the power chamber, and an atomized water mechanism is also equipped to spray atomized water into the mixing chamber, so as to increase the water content of the gas entering the power chamber.

[0010] As a specific embodiment of the present invention, a pressure gauge is also arranged in the power chamber to measure the gas pressure in the power chamber.

[0011] The present invention also discloses a method for testing the performance of high-temperature resistant drilling fluid. The filtration performance of the drilling fluid is measured by using the above-mentioned high-temperature resistant drilling fluid performance testing device, including the following steps: S1. Load the drilling fluid into the sample chamber, inject gas into the power chamber to drive the piston assembly to move until the drilling fluid overflows into the graduated cylinder; close the outlet of the sample chamber, inject gas into the power chamber and the drainage channel to increase the pressure, so as to avoid the vaporization of the drilling fluid during the later heating process. When injecting gas, the pressure of the sample chamber is greater than the pressure of the drainage channel; S2. Start the constant temperature jacket to heat the drilling fluid to the test temperature, and supplement gas to the sample chamber to adjust the pressure of the sample chamber to the test pressure; S3. Open the outlet of the sample chamber, supplement gas to the sample chamber to push the piston assembly to move, and during the movement, keep the pressure of the sample chamber constant; Among them, in steps S2 and S3, the pressure of the sample chamber is greater than the pressure of the drainage channel.

[0012] As a specific embodiment of the present invention, in steps S1 to S3, the pressure difference between the sample chamber and the drainage channel is constant.

[0013] As a specific embodiment of the present invention, it further includes: discharging the gas in the power chamber and the drainage channel after the drilling fluid filtration is completed, and during the discharging process, maintaining the pressure difference between the power chamber and the drainage channel stable.

[0014] The beneficial effects of the present invention are as follows: The high-temperature resistant drilling fluid performance testing device of the present invention arranges the filtering medium on the upper end face of the mud cup to avoid the influence of solid particle deposition on the filter cake formation; uses gas to drive the piston in the mud cup to move, and when the displacement is completed, the remaining displacement medium in the mud cup is gas, which does not need to be recovered and can be directly discharged to start the next round of experiments, saving experimental time; a drainage channel is arranged between the sealing rings of the piston to lead the leaked fluid outside the mud cup, thereby preventing gas from entering the drilling fluid and affecting the filtration loss of the drilling fluid. Combining the above features, it can quickly and accurately measure the filtration loss performance of the drilling fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the high-temperature resistant drilling fluid performance testing device in an embodiment of the present invention; Figure 2 is Figure 1 a schematic structural diagram of the piston assembly in Figure 3 is a schematic structural diagram of the piston assembly in another embodiment of the present invention; Figure 4 is a schematic structural diagram of the piston assembly in still another embodiment of the present invention; In the figure, mud cup 100, piston assembly 200, pressure gauge 300, graduated cylinder 400, constant temperature jacket 500, filtering medium 600, gas source device 700, cooler 900, sample chamber 110, power chamber 120, piston body 210, sealing ring 220, drainage channel 230, partition sealing ring 240, water-swellable rubber ring 250, mixing chamber 810, atomized water mechanism 820, upper sealing ring 221, lower sealing ring 222, first branch pipe 231, second branch pipe 232, main pipe 233, annular floating body 234, step surface 2331. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Next, in combination with the drawings and specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, the following described embodiments or technical features can be combined arbitrarily to form new embodiments.

[0017] Please refer to Figure 1 and Figure 2, which shows the overall structure of a specific embodiment of the high-temperature resistant drilling fluid performance testing device of the present invention. The high-temperature resistant drilling fluid performance testing device of the present invention includes a mud cup 100, a piston assembly 200, a pressure gauge 300, a graduated cylinder 400, a constant temperature jacket 500 and a gas source device 700. Among them, the mud cup 100 is a vertically arranged pressure vessel with openings at both ends and a filter medium 600 is provided on the inner wall of the top. The filter medium 600 is used to filter the drilling fluid, and filter paper or a filter screen can be selected. The graduated cylinder 400 is used to receive the drilling fluid passing through the filter medium 600. The constant temperature jacket 500 is used to heat the mud cup 100. These components are all conventional equipment in the industry, and the installation of the filter medium 600 also belongs to the conventional operation in the industry, which will not be elaborated here.

[0018] In the present invention, the piston assembly 200 is slidably and sealingly connected to the inner wall of the mud cup 100 and can slide axially along the mud cup 100. At the same time, the piston assembly 200 divides the interior of the mud cup 100 into two independent cavities, namely a sample cavity 110 and a power cavity 120. The sample cavity 110 is located above the power cavity 120 and is used to store the drilling fluid. The gas source device 700 is communicated with the power cavity 120 and is used to supplement gas into the power cavity 120 to drive the piston assembly 200 to move upward, thereby displacing the drilling fluid through the filter medium 600. The piston assembly 200 includes a piston body 210, two groups of sealing rings 220 and a drainage channel 230. Among them, the two groups of sealing rings 220 are arranged at intervals along the axial direction of the piston body 210. Each group of sealing rings 220 is fixed on the side wall of the piston body 210 and abuts against the inner wall of the mud cup 100, so as to seal the gap between the piston body 210 and the mud cup 100. The two groups of sealing rings 220, the inner wall of the mud cup 100 and the side wall of the piston body 210 enclose an annular cavity for accommodating the leaked fluid. The drainage channel 230 is arranged in the piston body 210 and is used to drain the fluid leaked into the annular cavity outside the mud cup 100, such as Figure 1 and Figure 2As shown, one end of the drainage channel 230 opens on the side wall of the piston body 210 and is located between two sets of sealing rings 220, and the other end opens and is communicated with the drainage and discharge pipe at the bottom of the mud cup 100 through a hose, so that the fluid leaking into the space between the two sealing rings 220 in the power chamber 120 and the sample chamber 110 can be drained out, preventing gas from entering the sample chamber 110 and contaminating the drilling fluid, thereby improving the measurement accuracy. There are two pressure gauges 300, which are respectively used to measure the pressures of the sample chamber 110 and the drainage channel 230, so as to monitor the pressure difference between the sample chamber 110 and the drainage channel 230. In the present invention, the gas source device 700 is also communicated with the drainage channel 230 and is used to supplement gas into the drainage channel 230 at the initial stage of the experiment. A valve is provided on the drainage and discharge pipe to facilitate the discharge of the leaked fluid during the experiment. By filling and discharging fluid into the drainage channel 230, the pressure of the sample chamber 110 can be maintained slightly higher than that of the drainage channel 230. In this way, the pressure difference on both sides of each set of sealing rings 220 can be reduced, the leakage amount can be decreased, and it can also be ensured that the leaked fluid does not enter the sample chamber 110. The smaller and more stable the specific value of this pressure difference is, the better. This is not only beneficial to reducing the leakage amount, but also beneficial to extending the service life of the sealing rings 220.

[0019] The present invention uses gas as the power medium to drive the piston assembly 200 to move. At the end of the displacement, the main remaining medium in the mud cup 100 is gas, which can be directly discharged without cooling and recovery, thus greatly saving the experiment time. At the same time, through the special piston assembly 200, the leaked fluid can be led out of the mud cup 100 to prevent gas from leaking into the sample chamber 110, thereby improving the accuracy of the test results.

[0020] When the device of the present invention is in use, it needs to be frequently heated and cooled, and the sealing rings 220 are prone to leakage. At the same time, the viscosity of gas is much lower than that of liquid, and under the same conditions, gas is more likely to leak than liquid. Therefore, the sealing rings 220 near the power chamber 120 are more prone to leakage. In order to reduce the leakage amount at this place, in some embodiments, such as Figure 3As shown, the two sets of sealing rings 220 are respectively called the upper sealing ring 221 and the lower sealing ring 222. The upper sealing ring 221 is located above the lower sealing ring 222. A separating sealing ring 240 is arranged between the two sets of sealing rings 220. The separating sealing ring 240 is arranged at intervals with the two sets of sealing rings 220. At the same time, the separating sealing ring 240 is fixed to the side wall of the piston body 210 and abuts against the inner wall of the mud cup 100, so as to further divide the annular cavity for accommodating the leaked fluid into two parts. A water-swellable rubber ring 250 is arranged between the lower sealing ring 222 and the separating sealing ring 240. It is made of water-swellable material. The gas in the power chamber 120 contains water vapor. Therefore, when the lower sealing ring 222 leaks, the water-swellable rubber ring 250 will contact the water vapor and expand for self-sealing, reducing the leakage amount. Of course, in order to prevent the fluid leaked from the upper sealing ring 221 from flowing freely and contacting the water-swellable rubber ring 250, causing it to expand at an inappropriate time, it is necessary to lead out the fluids leaked at the two sealing rings 220 respectively, as Figure 3 shown, the drainage channel 230 includes a first branch pipe 231, a second branch pipe 232 and a main pipe 233. Among them, the main pipe 233 is arranged vertically. One end opening of the first branch pipe 231 is located on the side wall of the piston body 210 and between the upper sealing ring 221 and the separating sealing ring 240, and the other end opening communicates with the main pipe 233. One end opening of the second branch pipe 232 is located on the side wall of the piston body 210 and between the water-swellable rubber ring 250 and the separating sealing ring 240, and the other end opening also communicates with the main pipe 233.

[0021] In the above embodiment, the leakage fluid is guided to be discharged by respectively arranging branch pipes. However, when an abnormal situation occurs where the amount of leaked liquid is much larger than the amount of leaked gas, there is still a risk that the drilling fluid will flow back along the second branch pipe 232 and contact the water-swellable rubber ring 250. Therefore, in some embodiments, the main pipe 233 is arranged as a stepped hole. The upper aperture of the stepped hole is small and the lower aperture is large. The connection port of the second branch pipe 232 and the main pipe 233 is located on the step surface 2331 of the stepped hole. A ring-shaped floating body 234 is arranged in the stepped hole. The ring-shaped floating body 234 can float on the liquid surface of the drilling fluid and the hollow part is greater than or equal to the size of the small hole in the stepped hole. Therefore, when the drilling fluid accumulates in the stepped hole, the ring-shaped floating body 234 will rise with the liquid level of the drilling fluid. When the upper end surface of the ring-shaped floating body 234 abuts against the step surface 2331 of the stepped hole, the connection port of the second branch pipe 232 and the main pipe 233 will be blocked. In this way, the fluid discharged from the first branch pipe 231 can be discharged through the hollow part of the ring-shaped floating body 234. At the same time, when the liquid level of the drilling fluid in the main pipe 233 has not reached the connection port of the second branch pipe 232 and the main pipe 233, the connection port of the second branch pipe 232 and the main pipe 233 can be automatically closed by using the ring-shaped floating body 234, avoiding the drilling fluid from flowing back to the water-swellable rubber ring 250.

[0022] In the present invention, when the water-swellable rubber ring 250 is adopted, it is necessary to carry water vapor through a gas. The commonly used gas can be nitrogen, etc., and its saturated water vapor content is not high. Therefore, measures can be taken to increase the water vapor content of the gas in the power chamber 120. In some embodiments, a mixing chamber 810 is provided between the gas source device 700 and the power chamber 120, and an atomized water mechanism 820 is also provided for spraying atomized water into the mixing chamber 810, so as to increase the water content of the gas entering the power chamber 120.

[0023] In addition, after the experiment, it is necessary to discharge the gas in the power chamber 120. During the exhaust process, the pressure in the sample chamber 110 will be higher than the pressure in the power chamber 120. In order to avoid too large a pressure difference on both sides of the lower sealing ring 222, in some embodiments, a pressure gauge 300 is also provided in the power chamber 120 for measuring the pressure in the power chamber 120. When discharging the gas after the displacement is completed, the pressure difference between the power chamber 120 and the drainage channel 230 is maintained stable, which is beneficial to extending the service life of the sealing ring 220.

[0024] For the drilling fluid passing through the filter medium 600, in some embodiments, a backpressure receiver can be provided for treatment, and in other embodiments, a cooler 900 can also be provided for cooling it. These are conventional components in existing filter loss meters and will not be elaborated here.

[0025] A method for testing the performance of a high-temperature resistant drilling fluid, which uses the above-mentioned high-temperature resistant drilling fluid performance testing device to measure the filtration performance of the drilling fluid, includes the following steps: S1. Load the drilling fluid into the sample chamber 110, inject gas into the power chamber 120 to drive the piston assembly 200 to move until the drilling fluid overflows into the graduated cylinder 400, so as to ensure that the pipeline is filled with liquid; close the outlet of the sample chamber 110, and inject gas into the power chamber 120 and the drainage channel 230 to increase the pressure to avoid vaporization of the drilling fluid during the subsequent heating process. When injecting gas, the pressure in the sample chamber 110 is greater than the pressure in the drainage channel 230, so as to avoid the fluid leaking between the two sets of sealing rings 220 from entering the sample chamber 110; S2. Start the constant temperature jacket 500 to heat the drilling fluid to the test temperature, and then supplement gas into the sample chamber 110 to adjust the pressure in the sample chamber 110 to the test pressure; S3. Open the outlet of the sample chamber 110, supplement gas into the sample chamber 110 to push the piston assembly 200 to move, and during the movement, maintain the pressure in the sample chamber 110 constant; Among them, in steps S2 and S3, the pressure in the sample chamber 110 is greater than the pressure in the drainage channel 230.

[0026] In some embodiments, when filling and discharging fluid in the drainage channel 230 in steps S1 to S3, the pressure difference between the sample chamber 110 and the drainage channel 230 is controlled to be constant, and this pressure difference is lower than the pressure difference that the sealing ring 220 can withstand, which is beneficial to reducing the leakage amount and extending the service life of the sealing ring 220.

[0027] In some embodiments, after the drilling fluid filtration is completed, the gas in the power chamber 120 and the drainage channel 230 is directly discharged. In other embodiments, after the drilling fluid filtration is completed, an exhaust operation is performed. During the exhaust operation, the pressure difference between the power chamber 120 and the drainage channel 230 is controlled to be constant, and this pressure difference is lower than the pressure difference that the sealing ring 220 can withstand, which is beneficial to reducing the leakage amount and extending the service life of the sealing ring 220.

[0028] For those skilled in the art, various corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all such changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A high-temperature resistant drilling fluid performance testing device, characterized in that, Comprising: A mud cup, vertically arranged and having a filter medium provided on the inner wall of its top; A piston assembly, slidably and sealingly connected to the inner wall of the mud cup and capable of sliding axially along the mud cup. The piston assembly divides the interior of the mud cup into a sample chamber and a power chamber, and the sample chamber is located above the power chamber. The piston assembly includes: A piston body; Two sets of sealing rings, arranged at intervals along the axial direction of the piston body. Each set of sealing rings is fixed to the side wall of the piston body and abuts against the inner wall of the mud cup; A drainage channel, arranged in the piston body. One end opening of the drainage channel is located on the side wall of the piston body and between the two sets of sealing rings, and the other end opening is communicated with a drainage discharge pipe at the bottom of the mud cup through a hose. A valve is provided on the drainage discharge pipe; Two pressure gauges, respectively used to measure the pressure of the sample chamber and the drainage channel; A gas source device, used to supply gas to the power chamber and the drainage channel; A measuring cylinder, used to receive the drilling fluid passing through the filter medium; A constant temperature jacket, used to heat the mud cup.

2. A high temperature resistant drilling fluid performance testing device according to claim 1, characterized in that: It further includes a partition sealing ring located between and spaced from the two sets of sealing rings. The partition sealing ring is fixed to the side wall of the piston body and abuts against the inner wall of the mud cup; the two sets of sealing rings are respectively an upper sealing ring and a lower sealing ring located below the upper sealing ring. A water-swellable rubber ring is provided between the lower sealing ring and the partition sealing ring; The drainage channel includes: A first branch pipe, one end opening of which is located on the side wall of the piston body and between the upper sealing ring and the partition sealing ring; A second branch pipe, one end opening of which is located on the side wall of the piston body and between the water-swellable rubber ring and the partition sealing ring; A vertically arranged main pipe, the other ends of the first branch pipe and the second branch pipe are respectively communicated with the main pipe; The gas in the power chamber is a gas containing water vapor.

3. The high-temperature resistant drilling fluid performance testing device according to claim 2, wherein The main pipe is a stepped hole, and the connection port of the second branch pipe and the main pipe is located on the step surface of the stepped hole; a ring-shaped floating body is provided in the stepped hole. The ring-shaped floating body can float on the liquid surface of the drilling fluid and the hollow part is greater than or equal to the size of the small hole in the stepped hole, so that when the upper end surface of the ring-shaped floating body abuts against the step surface of the stepped hole, the connection port of the second branch pipe and the main pipe can be blocked.

4. The high-temperature resistant drilling fluid performance testing device according to claim 2, characterized in that, A mixing chamber is provided between the gas source device and the power chamber, and an atomized water mechanism is also provided, used to spray atomized water into the mixing chamber.

5. The high-temperature resistant drilling fluid performance testing device according to claim 2, characterized in that, A pressure gauge is also provided in the power chamber, used to measure the gas pressure in the power chamber.

6. A method for testing the performance of a high-temperature resistant drilling fluid, comprising testing the fluid loss performance of the drilling fluid using a high-temperature resistant drilling fluid performance testing device according to any one of claims 1 to 5, characterized in that: Including the following steps: S1. Load drilling fluid into the sample chamber, inject gas into the power chamber to drive the piston assembly to move until the drilling fluid overflows into the measuring cylinder; close the outlet of the sample chamber, inject gas into the power chamber and the drainage channel to increase the pressure to avoid vaporization of the drilling fluid during the subsequent heating process. When injecting gas to increase the pressure, the pressure of the sample chamber is greater than the pressure of the drainage channel; S2. Start the constant temperature jacket to heat the drilling fluid to the test temperature, and supplement gas to the sample chamber to adjust the pressure of the sample chamber to the test pressure; S3. Open the outlet of the sample chamber, replenish the gas in the sample chamber to push the piston assembly to move, and during the movement, maintain the pressure in the sample chamber constant; Among them, in steps S2 and S3, the pressure in the sample chamber is greater than the pressure in the drainage channel.

7. A method for testing the performance of a high-temperature resistant drilling fluid according to claim 6, characterized in that, In steps S1 to S3, the pressure difference between the sample chamber and the drainage channel is constant.

8. A method for testing the performance of high temperature resistant drilling fluid according to claim 6, characterized in that: After the drilling fluid filtration is completed, discharge the gas in the power chamber and the drainage channel, and during the discharge process, maintain the pressure difference between the power chamber and the drainage channel constant.

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