Device and method for testing high-pressure physical properties of oil and gas reservoir fluid

Abstract

The invention provides an oil and gas reservoir fluid high-pressure physical property testing device and method, and belongs to the field of oil and gas field development, the device is composed of a constant temperature box, a PVT kettle body, a screw pump, a piston, a camera, a light source module and a stirrer, the PVT kettle body is placed in the constant temperature box, the PVT kettle body is made of a transparent material, a cylindrical inner cavity is formed in the PVT kettle body, and the screw pump is arranged in the inner cavity; a first guide hole and a second guide hole are respectively formed in the upper part and the lower part of the inner cavity to form a channel for fluid to enter and exit from the PVT kettle body, the piston is arranged in the inner cavity, the screw pump is connected with the piston, the stirrer is arranged in the inner cavity, the camera is arranged outside the constant-temperature box, and the light source module is arranged inside the constant-temperature box. The method is implemented through the testing device and comprises a high-pressure fluid sample transfer test and a single degassing test. According to the device and the method provided by the invention, the high-pressure physical property parameters of the fluid can be accurately measured by a small amount of samples, and key technical indexes are provided for oil-gas field development.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development. Specifically, it relates to a high-pressure physical property testing device for reservoir fluids and a high-pressure physical property testing method for reservoir fluids. Background Art

[0002] The high-temperature and high-pressure PVT analysis and testing of reservoir fluids is an essential experiment for determining the physical properties of reservoir fluids, and is widely used in fields such as oil and gas field development, CO2 flooding and storage. The principle of PVT analysis and testing is to fill a certain amount of fluid into an analysis container (PVT cell), use a high-pressure metering pump to change the pressure (P) parameter and volume (V) parameter of the fluid, use a heating and temperature control system to change the temperature (T) parameter of the fluid, observe the phase behavior and change characteristics of the fluid, and record the parameter values under different conditions. Through the PVT analysis and testing of the fluid, physical property parameters such as the compressibility coefficient, thermal expansion coefficient, saturation pressure, volume coefficient, and dissolved gas-oil ratio of the fluid can be measured and calculated.

[0003] The maximum volume of common PVT analyzers is generally about 100 - 500 ml, and the required fluid sample volume is relatively large. Currently, common PVT analyzers are divided into two categories: single-sided visible and single-sided non-visible. The non-visible PVT cell has a lower cost, but it can no longer meet the needs of current oil and gas development research and production, and is gradually facing elimination. The single-sided visible PVT cell is the most widely used type at present, but the visualization degree of this type of PVT cell is still low. When observing the fluid state, an internal light source is required, the color of the collected image is distorted, and the position of the gas-liquid interface cannot be accurately judged in specific situations. Therefore, it is of great significance to develop a fully visible high-pressure physical property testing device for fluids. Summary of the Invention

[0004] Aiming at the technical problems of the low visualization degree of the single-sided visible PVT analyzer in the prior art and the inability to accurately judge the position of the gas-liquid interface in specific situations, the present invention provides a high-pressure physical property testing device and method for reservoir fluids. Using this device can achieve full-round visualization of the physical property analysis experiment process of reservoir fluids, and can accurately measure the high-pressure physical property parameters of the fluid with a small amount of samples, providing key technical indicators for oil and gas field development.

[0005] To achieve the above object, on the one hand, the present invention provides a high-pressure physical property testing device for reservoir fluids. The testing device includes: a constant temperature box, a PVT cell, a screw pump, a piston, a camera, a light source module, and a stirrer; wherein, the PVT cell is made of a transparent material, and a cylindrical inner cavity is formed inside the PVT cell. A first guide eye and a second guide eye are respectively arranged at the upper and lower parts of the inner cavity to form a channel for the fluid to enter and exit the PVT cell; the piston is arranged in the inner cavity and has an outer diameter equal to the inner diameter of the inner cavity; the screw pump is connected to the piston and is used to control the piston to move along the length direction of the inner cavity to change the volume and pressure of the fluid in the inner cavity; the PVT cell is placed in the constant temperature box, and the constant temperature box is used to adjust the fluid temperature in the PVT cell to the sample transfer temperature; the stirrer is used to stir the fluid in the PVT cell; the camera is arranged outside the constant temperature box and is used to capture the image inside the PVT cell; the light source module is arranged inside the constant temperature box and is used to irradiate the fluid in the PVT cell.

[0006] In an exemplary embodiment of the present invention, a viewing window having the same size as the inner cavity may be opened on the constant temperature box, and the camera is located outside the viewing window.

[0007] In an exemplary embodiment of the present invention, the stirrer may include a magnetic stirring table and a magnetic stirrer. The magnetic stirrer is located in the inner cavity, and the magnetic stirring table is located at the bottom of the inner cavity and is used to control the rotation of the magnetic stirrer.

[0008] In an exemplary embodiment of the present invention, the transparent material may be sapphire glass.

[0009] In an exemplary embodiment of the present invention, a piston seal ring may be arranged between the piston and the inner cavity, and the piston seal ring is made of fluorine-containing rubber.

[0010] On the other hand, the present invention provides a method for testing the high-pressure physical properties of reservoir fluids. The testing method is implemented by the above-mentioned high-pressure physical property testing device for reservoir fluids, and specifically, when performing a high-pressure fluid sampling transfer test, the method includes the following steps: Connect the sample intermediate container to the second guide eye of the PVT cell body through the second valve, and connect the evacuation pipeline to the first guide eye of the PVT cell body through the first valve; Set the temperature of the constant temperature box to the sampling transfer temperature and stabilize for a predetermined time; Control the screw pump to move the piston to the bottom of the inner cavity and evacuate from the second valve. After completion, close all valves; Keep the sample intermediate container always at the sampling transfer pressure, open the second valve to allow the fluid to enter the inner cavity of the PVT cell body, and control the screw pump to move the piston upward until it exceeds the first guide eye and then stop the pump; Open the first valve to slowly discharge the fluid, and at the same time keep the fluid transferred at the second guide eye until it is determined that a predetermined volume of fluid is continuously discharged from the first guide eye, then close the first valve; Control the screw pump to move the piston downward to a position at a predetermined length from the bottom of the inner cavity and then stop the pump; Close the second valve to complete the high-pressure fluid sampling transfer.

[0011] In another exemplary embodiment of the present invention, during the sampling transfer process, it is possible to determine whether the fluid in the inner cavity is in a single-phase state.

[0012] In another exemplary embodiment of the present invention, the sampling transfer temperature can be set to 20°C to 200°C.

[0013] In another exemplary embodiment of the present invention, specifically, when performing a single-stage degassing test, the method may include the following steps: After completing the high-pressure fluid sampling transfer, connect the gas meter to the first guide eye of the PVT cell body through the first valve, measure the atmospheric pressure and the indoor temperature and evacuate the gas meter; Control the screw pump to move the piston upward until it exceeds the first guide eye and then stop the pump; Open the first valve and control the gas in the inner cavity to be slowly discharged to the gas meter; After discharging all the gas in the inner cavity, restore the pressure in the gas meter to the atmospheric pressure and close all valves; Determine the liquid-phase volume remaining in the inner cavity by analyzing the images collected by the camera; Read the gas-phase volumes in the gas meter, pipeline, first valve, and inner cavity respectively to determine the total gas-phase volume.

[0014] In another exemplary embodiment of the present invention, the ratio of the total gas-phase volume to the liquid-phase volume can be determined as the gas-oil ratio.

[0015] Through the technical solution provided by the present invention, the present invention has at least the following technical effects:

[0016] (1) The high-pressure physical property testing device for reservoir fluids provided by the present invention realizes the miniaturization and full visualization of the fluid physical property testing device, and at the same time establishes a supporting experimental and analysis method, which is applicable to the high-pressure physical property testing and analysis of reservoir fluids;

[0017] (2) The oil and gas reservoir fluid high-pressure physical property testing device provided by the present invention requires less fluid sample volume, which is beneficial for repeated experiments and saving costs such as sampling and sample preparation.

[0018] (3) The oil and gas reservoir fluid high-pressure physical property testing device provided by the present invention has a high degree of visualization. The collected images can accurately determine the position of the gas-liquid interface, which is beneficial for improving the measurement accuracy of the fluid volume.

[0019] Other features and advantages of the present invention will be described in detail in the following specific implementation section. Description of the Drawings

[0020] The drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementation, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0021] Figure 1 It is a schematic structural diagram of the oil and gas reservoir fluid high-pressure physical property testing device provided by the embodiment of the present invention.

[0022] Description of the Reference Numerals in the Drawings

[0023] 1 - Constant temperature box, 2 - PVT kettle body, 3 - High-precision screw pump, 4 - Piston, 5 - High-definition camera, ⑥ - Visual window, 7 - Magnetic stirrer, 8 - Magnetic stirring table, 9 - LED light source, 10 - First valve, 11 - Second valve, 12 - Sample intermediate container. Specific Implementation

[0024] The following will describe in detail the specific implementation of the embodiments of the present invention with reference to the drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiments of the present invention and does not limit the embodiments of the present invention.

[0025] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0026] In the present invention, unless otherwise stated, the orientation words such as "upper, lower, top, bottom" are usually in the direction shown in the drawings or in the vertical, perpendicular or gravitational direction for describing the relative position relationship of each component. "First", "second", etc. are only for convenience of description and easy distinction, and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, terms such as "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection; it can be a wired connection or a wireless connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the prior art, the maximum volume of a commonly used PVT analyzer is generally about 100 - 500 ml, and the required amount of fluid sample is relatively large. In addition, the existing PVT analyzers are usually visible from one side only, and their visualization degree is still relatively low. When observing the fluid state, an internal light source is required, and the color of the collected images is distorted, and it is impossible to accurately judge the position of the gas-liquid interface in specific cases. Therefore, it is of great significance to develop a small-sized fully visible fluid high-pressure physical property testing device.

[0029] The inventors have found through research that there are the following problems to be solved in the development of a small-sized fully visible fluid high-pressure physical property testing device: (1) Due to the small volume, it is required to improve the measurement accuracy of the fluid volume. A high-precision metering pump needs to be used, and at the same time, it is required to reduce the influence of the dead volume on the experimental results; (2) The PVT analyzer needs to be equipped with an internal stirrer to quickly bring the fluid to the phase equilibrium state, but the existing stirrer systems are not applicable to the miniaturized PVT analyzer; (3) Due to the small amount of sample contained, the single-stage degassing experiment in the current national standard cannot be completed in the miniaturized PVT analyzer, and a new single-stage degassing experiment test method applicable to the small PVT analyzer needs to be formed; (4) Due to the requirement of full visibility, the heating and insulation device of the PVT analyzer cannot adopt the form of a heating and insulation sleeve, and using an external constant temperature box puts higher requirements on the settings of the light source, high-definition camera, etc.

[0030] In view of the above problems, the present invention proposes an oil and gas reservoir fluid high-pressure physical property testing device and method. The device mainly consists of an external constant temperature box and a fully visible PTV kettle body. The PTV kettle body is made of sapphire glass, and an inner cavity with a maximum volume not exceeding 10 cm3 is designed in the kettle body as the container for the fluid, and the required amount of sample is extremely small. In addition, based on the testing device of the present invention, the high-pressure fluid sample transfer and single-stage degassing experiment processes are redesigned to form an analysis method applicable to the small-sized visible fluid high-pressure physical property testing device. Compared with the PVT analyzers in the prior art, this device can achieve full visibility of the oil and gas reservoir fluid physical property analysis experimental process, and can accurately measure the high-pressure physical property parameters of the fluid with a small amount of sample, providing key technical indicators for oil and gas field development.

[0031] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. The following several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in some embodiments again.

[0032] An embodiment of the present invention provides a high-pressure physical property testing device for reservoir fluids, which includes a constant temperature box, a PVT cell, a screw pump, a piston, a camera, a light source module, and a stirrer.

[0033] Specifically, the PVT cell is made of a transparent material, and a cylindrical inner cavity is formed inside the PVT cell. A first guide hole and a second guide hole are respectively arranged at the upper and lower parts of the inner cavity to form a channel for fluid to enter and exit the PVT cell. The piston is arranged in the inner cavity and has an outer diameter equal to the inner diameter of the inner cavity. The screw pump is connected to the piston and is used to control the piston to move along the length direction of the inner cavity to change the volume and pressure of the fluid in the inner cavity. The screw pump and the piston cooperate with each other to simulate different pressure conditions and volume conditions. The main function of the screw pump is to provide pressure to change the position of the piston. When the position of the piston changes, the fluid in the PVT cell is compressed or expanded, thereby realizing the change of the volume and pressure of the fluid in the inner cavity. The PVT cell is placed in the constant temperature box, and the constant temperature box is used to adjust the fluid temperature in the PVT cell to the sample transfer temperature. The stirrer is used to stir the fluid in the PVT cell. The camera is arranged outside the constant temperature box and is used to capture the image inside the PVT cell. Here, in order to improve the measurement accuracy of the fluid volume, a high-definition camera should be used to collect images in real time. The light source module is arranged inside the constant temperature box and is used to irradiate the fluid in the PVT cell. For example, the light source module can be arranged on the inner wall of the constant temperature box and is directly opposite to the inner cavity part of the PVT cell to ensure that the fluid in the inner cavity is in a relatively bright environment, which is also beneficial to subsequent determination of the fluid volume at different positions in the PVT cell by analyzing the collected images.

[0034] In order to ensure the sealing performance and visibility, in this embodiment, a viewing window with the same size as the inner cavity is opened on the constant temperature box, and the camera is located outside the viewing window. The viewing window area can be sealed with a transparent material, which can ensure the sealing performance and light transmittance during multiple high-pressure fluid physical property tests.

[0035] In order to ensure that the fluid quickly reaches the phase equilibrium state, in this embodiment, the stirrer can be composed of a magnetic stirring table and a magnetic stirrer. The magnetic stirrer is located in the inner cavity, and the magnetic stirring table is located at the bottom of the inner cavity and is used to control the rotation of the magnetic stirrer. When the magnetic stirring table is started, the magnetic stirrer located in the inner cavity rotates rapidly under the control of the magnetic stirring table, thereby driving the fluid to rotate at a high speed to achieve the purpose of uniform stirring.

[0036] To ensure the sealing between the piston and the inner cavity, prevent fluid leakage and reduce friction, in this embodiment, a piston seal ring can be provided between the piston and the inner cavity. In addition, the piston seal ring can be made of fluororubber to prevent acid corrosion.

[0037] To ensure that the PVT kettle body has good optical properties, sapphire glass can be used as the material for making the PVT kettle body.

[0038] The embodiment of the present invention also provides a method for testing the high-pressure physical properties of reservoir fluids, and this testing method is implemented by the above-mentioned testing device for the high-pressure physical properties of reservoir fluids.

[0039] Specifically, when implementing the high-pressure fluid sampling transfer test by using the above-mentioned testing device for the high-pressure physical properties of reservoir fluids, its specific implementation process is as follows.

[0040] Step S101: Connect the sample intermediate container to the second guide eye of the PVT kettle body through the second valve, and connect the evacuation pipeline to the first guide eye of the PVT kettle body through the first valve.

[0041] Step S102: Set the temperature of the constant temperature box to the sampling transfer temperature and stabilize for a predetermined time.

[0042] For example, the range of the sampling transfer temperature can be set to 20°C to 200°C. After controlling the temperature of the constant temperature box to be set to the sampling transfer temperature, it can be stabilized for more than 2 hours.

[0043] Step S103: Control the screw pump to move the piston to the bottom of the inner cavity and evacuate from the second valve. After completion, close all valves.

[0044] Step S104: Keep the sample intermediate container always at the sampling transfer pressure (constant pressure mode), open the second valve to allow the fluid to enter the inner cavity of the PVT kettle body, and control the screw pump to move the piston upward until it exceeds the first guide eye and then stop the pump.

[0045] Step S105: Open the first valve to slowly discharge the fluid, and at the same time keep the fluid transferred at the second guide eye until it is determined that a predetermined volume of fluid has been continuously discharged from the first guide eye, then close the first valve.

[0046] For example, the first valve can be closed after observing that about 5 ml of fluid has been continuously discharged from the first guide eye.

[0047] In addition, during the sampling transfer process, determine whether the fluid in the inner cavity is in a single-phase state.

[0048] Step S106: Control the screw pump to move the piston downward to a position at a predetermined length from the bottom of the inner cavity and then stop the pump.

[0049] For example, the screw pump and the piston can be controlled to be pushed down again to a position about 2 cm away from the bottom surface of the inner cavity and then the pump is stopped.

[0050] Step S107: Close the second valve to complete the transfer of high-pressure fluid.

[0051] When implementing a single-stage degassing test using the above-mentioned high-pressure physical property testing device for reservoir fluids, the specific implementation process is as follows.

[0052] Step S201: After completing the transfer of high-pressure fluid, connect the gas meter to the first guide eye of the PVT cell through the first valve, measure the atmospheric pressure and the indoor temperature, and evacuate the gas meter.

[0053] Step S202: Control the screw pump to move the piston upward until it exceeds the first guide eye and then stop the pump. At this time, the fluid in the PTV cell should be in a gas-liquid two-phase state, with the gas phase in the upper part and the liquid phase in the lower part.

[0054] Step S203: Open the first valve and control the gas in the inner cavity to be slowly discharged into the gas meter. During this process, the pressure in the gas meter should be maintained near the atmospheric pressure.

[0055] Step S204: After discharging all the gas in the inner cavity, restore the pressure in the gas meter to the atmospheric pressure and close all valves.

[0056] Step S205: Determine the volume of the liquid phase remaining in the inner cavity by analyzing the images collected by the analysis camera.

[0057] Step S206: Read the gas volumes in the gas meter, pipeline, first valve, and inner cavity respectively to determine the total gas volume.

[0058] In addition, the gas-oil ratio can also be determined based on the total gas volume and the liquid volume, specifically, gas-oil ratio = total gas volume / liquid volume.

[0059] When implementing other experimental contents using the above-mentioned high-pressure physical property testing device for reservoir fluids, it can be carried out with reference to the national standard "GB / T 26981-2020 Analysis Method for Physical Properties of Reservoir Fluids".

[0060] To better understand the above exemplary embodiments of the present invention, the following further describes them in combination with specific examples and drawings.

[0061] As Figure 1 shown, a high-pressure physical property testing device for reservoir fluids consists of a constant temperature box 1, a PVT cell 2, a high-precision screw pump 3, a piston 4, a high-definition camera 5, a viewing window 6, a magnetic stirrer 7, a magnetic stirring table 8, an LED light source 9, a first valve 10, and a second valve 11.

[0062] Among them, the PVT kettle body 2 is placed in the constant temperature box 1, and the constant temperature box 1 is used to control the fluid temperature inside the PVT kettle body 2, and the temperature control range is 20°C to 200°C.

[0063] A cylindrical inner cavity is designed at the center of the PVT kettle body 2 as a container for the fluid, and its wall thickness is determined by the design pressure. The PVT kettle body is made of sapphire glass material, and full-visual PTV testing can be achieved. Considering the influence of capillary pressure when there are two phases in the fluid, the inner cavity diameter is designed to be 1 cm, and the capillary pressure generated at this time will not be greater than 10 Pa, and its influence can be ignored for high-pressure physical property testing. On this basis, the height of the inner cavity cylinder is designed to be 15 cm, and the maximum volume is 11.78 cm3. Considering the reserved limiting volume and the volume occupied by the piston, etc., the maximum volume does not exceed 10 cm3, and the required sample amount is extremely small.

[0064] A first guide eye with an inner diameter of 1 / 16 inch is designed at a position 5 cm from the top surface of the inner cavity as a fluid outlet, and a second guide eye with an inner diameter of 1 / 16 inch is designed at the bottom of the inner cavity as a fluid inlet. The first guide eye and the second guide eye can form a channel for the fluid to enter and exit the PVT kettle body.

[0065] The inner cavity of the PVT kettle body 2 is sealed by a cylindrical piston 4, and a piston seal ring is arranged between the piston and the inner cavity. The piston seal ring is made of fluorine-containing rubber material to prevent acid corrosion. The top of the piston 4 is connected to the high-precision screw pump 3. By controlling the screw pump and the piston movement, the volume and pressure of the fluid in the kettle body can be changed, and the pressure measured by the high-precision screw pump is the fluid pressure.

[0066] A magnetic stirrer 7 with a length of 0.8 cm is placed in the inner cavity of the PVT kettle body 2, and it is controlled to rotate in the inner cavity by the magnetic stirring table 8 under the inner cavity, so as to achieve the purpose of stirring the fluid.

[0067] Two fixed four-way valves are also provided outside the PVT kettle body 2, namely the first valve 10 and the second valve 11. One end of the first valve 10 is connected to the first guide eye of the PVT kettle body 2, and the other end of the first valve 10 is connected to the evacuation pipeline or other experimental devices. One end of the second valve 11 is connected to the second guide eye of the PVT kettle body 2, and the other end of the second valve 11 is connected to the sample intermediate container 12.

[0068] On one side of the incubator 1 close to the PVT kettle body 2, an opening with the same size as the inner cavity is designed. A viewing window 6 is set on the opening, and a high-definition camera 5 is placed outside the viewing window 6 for real-time image acquisition. The LED light source 9 is arranged on the inner wall of the incubator 1 for irradiating the fluid area in the inner cavity. The images collected by the high-definition camera need to be further processed to analyze and calculate the fluid volume. Using the method of fluid volume calibration, the dead volume of the device and the fluid volumes at different positions in the sapphire glass kettle body are measured. During the later experiment process, the volumes of the gas-liquid two phases are determined according to the position of the fluid interface in the collected images, and the volume accuracy is related to the image accuracy.

[0069] The condensate gas sample from Well T1 is compounded. The formation temperature of Well T1 is 70.4 °C and the formation pressure is 31.45 MPa.

[0070] The specific process of implementing the high-pressure fluid sampling process for the T1 condensate gas sample using the above physical property testing device is as follows:

[0071] (1) Control the temperature of the incubator to 70.4 °C and keep it stable for 2 hours;

[0072] (2) Control the screw pump to push the piston to the bottom and evacuate from the second valve below the kettle body. After completion, close all valves;

[0073] (3) Keep the intermediate container at the sample end under a sampling pressure of 40 MPa (constant pressure mode) all the time. Open the second valve to allow the fluid sample to enter the sapphire glass kettle body. Control the screw pump and the piston to move upward until it exceeds the upper first guide eye and then stop the pump;

[0074] (4) Open the first valve above the kettle body to slowly discharge the fluid, and at the same time keep the transfer of the fluid at the sample end. After continuously discharging 5.3 ml of fluid, close the first valve; During the sampling process, observe that the fluid sample in the sapphire glass kettle body always remains in a single-phase state;

[0075] (5) Control the high-precision screw pump and the piston to push down again to a position 2 cm away from the bottom surface and stop the pump;

[0076] (6) Close the second valve below the kettle body to complete the high-pressure fluid sampling.

[0077] The specific process of implementing a single-stage degassing experiment on the T1 condensate gas sample using the above physical property testing device and measuring the fluid gas-oil ratio parameter is as follows:

[0078] (1) Complete the high-pressure fluid sampling and connect the first valve above the kettle body to the gas meter. Measure the atmospheric pressure at this time as 0.1003 MPa and the indoor temperature as 22.5 °C, and evacuate the gas meter;

[0079] (2) Stop the pump when the control screw pump and the piston move upward beyond the upper first guide eye. At this time, the fluid in the PTV kettle is in a gas-liquid two-phase state, with the gas phase in the upper part and the liquid phase in the lower part.

[0080] (3) Open the first valve above the kettle body and control the slow discharge of the upper gas into the gas meter. During the process, keep the pressure in the gas meter within the range of 0.09 - 0.11 MPa.

[0081] (4) Completely discharge the gas inside the kettle body, restore the pressure in the gas meter to 0.1003 MPa, and close all valves.

[0082] (5) Measure the volume of the liquid phase remaining in the kettle body at this time as 0.154 ml through image acquisition and analysis.

[0083] (6) Read the volume of the gas in the gas meter, and add the sum of the volumes of the gas in the pipeline, valves, and the gas phase outside the liquid phase in the kettle body to obtain the total gas volume of 228.40 ml.

[0084] (7) Measure the gas-oil ratio = total gas volume / liquid phase volume = 1483.09 m3 / m3.

[0085] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0086] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0087] Furthermore, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A high-pressure physical property testing device for reservoir fluids, characterized in that, The test device includes: a constant temperature box, a PVT kettle body, a screw pump, a piston, a camera, a light source module, and a stirrer; The PVT kettle body is made of a transparent material, and a cylindrical inner cavity is formed inside the PVT kettle body. A first guide eye and a second guide eye are respectively arranged at the upper and lower parts of the inner cavity to form a channel for fluid to enter and exit the PVT kettle body; The piston is arranged in the inner cavity and has an outer diameter equal to the inner diameter of the inner cavity; The screw pump is connected to the piston and is used to control the piston to move along the length direction of the inner cavity to change the volume and pressure of the fluid in the inner cavity; The PVT kettle body is placed in the constant temperature box, and the constant temperature box is used to adjust the fluid temperature in the PVT kettle body to the sample transfer temperature; The stirrer is used to stir the fluid in the PVT kettle body; The camera is arranged outside the constant temperature box and is used to capture images inside the PVT kettle body; The light source module is arranged inside the constant temperature box and is used to irradiate the fluid inside the PVT kettle body.

2. The high-pressure physical property testing device for reservoir fluids according to claim 1, characterized in that A viewing window equal in size to the inner cavity is opened on the constant temperature box, and the camera is located outside the viewing window.

3. The high-pressure physical property testing device for reservoir fluids according to claim 1, characterized in that The stirrer includes a magnetic stirring table and a magnetic stirring bar. The magnetic stirring bar is located in the inner cavity, and the magnetic stirring table is located at the bottom of the inner cavity and is used to control the rotation of the magnetic stirring bar.

4. The high-pressure physical property testing device for reservoir fluids according to claim 1, wherein The transparent material is sapphire glass.

5. The high-pressure physical property testing device for reservoir fluids according to claim 1, characterized in that, A piston sealing ring is arranged between the piston and the inner cavity, and the piston sealing ring is made of fluorine-containing rubber.

6. A method for testing the high-pressure physical properties of reservoir fluids, characterized in that, The test method is implemented by the oil and gas reservoir fluid high-pressure physical property test device described in any one of claims 1 to 5; when implementing the high-pressure fluid sample transfer test, the test method includes the following steps: Connect the sample intermediate container to the second guide eye of the PVT kettle body through the second valve, and connect the evacuation pipeline to the first guide eye of the PVT kettle body through the first valve; Set the temperature of the constant temperature box to the sample transfer temperature and stabilize for a predetermined time; Control the screw pump to move the piston to the bottom of the inner cavity and evacuate from the second valve. After completion, close all valves; Keep the sample intermediate container always at the sample transfer pressure, open the second valve to allow the fluid to enter the inner cavity of the PVT kettle body, and control the screw pump to move the piston upward until it exceeds the first guide eye and then stop the pump; Open the first valve to slowly discharge the fluid, and at the same time keep the fluid transferred at the second guide eye until it is determined that a predetermined volume of fluid is continuously discharged from the first guide eye, and then close the first valve; Control the screw pump to move the piston downward to a position at a predetermined length from the bottom of the inner cavity and then stop the pump; Close the second valve to complete the high-pressure fluid sample transfer.

7. The high-pressure physical property testing method for reservoir fluids according to claim 6, characterized in that, During the sample transfer process, determine whether the fluid in the inner cavity is in a single-phase state.

8. The high-pressure physical property testing method for reservoir fluids according to claim 6, characterized in that, The sample transfer temperature is set to 20°C to 200°C.

9. The high-pressure physical property testing method for reservoir fluids according to claim 6, characterized in that, When implementing a single-stage degassing test, the method includes the following steps: After completing the high-pressure fluid sample transfer, connect the gas meter to the first guide eye of the PVT kettle body through the first valve, measure the atmospheric pressure and the indoor temperature, and evacuate the gas meter; Control the screw pump to move the piston upward until it exceeds the first guide eye and then stop the pump; Open the first valve and control the gas in the inner cavity to slowly discharge into the gas meter; After discharging all the gas in the inner cavity, restore the pressure in the gas meter to the atmospheric pressure and close all valves; Determine the liquid phase volume remaining in the inner cavity by analyzing the images collected by the camera; Read the gas flow meter, pipeline, first valve, and the gas phase volume in the inner cavity respectively to determine the total gas phase volume.

10. The high-pressure physical property testing method for reservoir fluids according to claim 9, wherein, Determine the gas-oil ratio as the ratio of the total gas phase volume to the liquid phase volume.

Images