Fracturing fluid performance evaluation device and evaluation method

Abstract

The application provides a fracturing fluid performance evaluation device and method. The device comprises a liquid storage tank, a first plunger pump, a one-way valve, an experimental pipeline and a water outlet valve connected in sequence. The device further comprises a second plunger pump, a heating device, a temperature sensor, a differential pressure sensor and a processor. The water outlet of the second plunger pump is connected to one end of the experimental pipeline close to the one-way valve. The water inlet of the second plunger pump is connected to one end of the experimental pipeline close to the water outlet valve. The water outlet of the second plunger pump is provided with a first valve. The water inlet of the second plunger pump is provided with a second valve. The heating device is arranged outside the experimental pipeline. The sensing end of the temperature sensor is arranged at the opening of one end of the experimental pipeline close to the first plunger pump. The two sensing ends of the differential pressure sensor are arranged at the openings of the two ends of the experimental pipeline. The processor is signal-connected with the temperature sensor and the differential pressure sensor. The evaluation device and method can obtain data of fluid loss that is closer to the actual situation.

Description

Technical Field

[0001] This invention relates to the field of experimental equipment technology, and in particular to a fracturing fluid performance evaluation device and evaluation method. Background Technology

[0002] Deep and ultra-deep oil reservoirs represent a crucial successor force in my country's onshore oil and gas exploration, characterized by high yields, significant development challenges, and high costs. The most significant development difficulties in ultra-deep oil and gas reservoirs lie in their great depth, high temperature, and high pressure, reaching depths exceeding 8000 meters, temperatures exceeding 200°C, and bottom-hole pressures exceeding 180 MPa. Hydraulic fracturing is a key technology for the efficient development of deep tight oil and gas reservoirs. Compared to conventional reservoirs, the high-temperature, high-pressure, and high-stress environment of ultra-deep reservoirs significantly impacts fracturing fluids, proppant, and other fracturing materials, thus affecting reservoir stimulation effectiveness. Therefore, conducting targeted fracturing material evaluation experiments specifically for deep reservoirs and clarifying the influence of temperature, pressure, and reservoir porosity and permeability on fracturing materials is of great significance for achieving efficient fracturing stimulation of ultra-deep reservoirs.

[0003] Currently, various fracturing fluid evaluation experiments have been conducted in field and research institutions. These typically involve using ambient temperature tubular side-pressure devices to simulate fluid flow in pipelines during field operations, determining pipeline friction, and evaluating the fracturing fluid's friction-reducing performance. Rotational viscometers or rheometers are used to measure the viscosity of the fracturing fluid under high temperature and high shear conditions to evaluate its temperature adaptability. Core holders or simulated plate devices are used to measure fracturing fluid filtration. However, the performance evaluation of fracturing fluids under high temperature and high pressure environments is relatively incomplete. There is a lack of devices to simulate pipeline friction measurement during the gradual temperature increase process of fracturing fluid delivery to the reservoir, and devices to simulate fracturing fluid filtration in natural dynamic fractures under high temperature and high pressure conditions.

[0004] For example, Chinese patent CN110231248A discloses an experimental device and working method for measuring fluid friction, which includes a liquid supply system, a well system and a fracture system. However, this solution cannot accurately simulate the friction change trend of the liquid gradually heating up in the pipeline when measuring pipeline friction.

[0005] Therefore, there is an urgent need for an experimental apparatus and method applicable to the performance evaluation of deep and ultra-deep fracturing fluids. Summary of the Invention

[0006] In view of this, the present invention proposes a fracturing fluid performance evaluation device and method, aiming to provide an experimental evaluation device and method that can simulate the environment of deep and ultra-deep oil reservoirs.

[0007] The technical solution of this invention is implemented as follows: This invention provides a fracturing fluid performance evaluation device, which includes: a storage tank, a first plunger pump, a one-way valve, an experimental pipeline, and an outlet valve connected in sequence; it also includes a second plunger pump, a heating device, a temperature sensor, a differential pressure sensor, and a processor. The outlet of the second plunger pump is connected to the end of the experimental pipeline near the one-way valve, and the inlet of the second plunger pump is connected to the end of the experimental pipeline near the outlet valve. A first valve is provided at the outlet of the second plunger pump, and a second valve is provided at the inlet of the second plunger pump. A heating device is sleeved on the outside of the experimental pipeline. The sensing end of the temperature sensor is located at the opening of the experimental pipeline near the first plunger pump. The two sensing ends of the differential pressure sensor are respectively located at the openings at both ends of the experimental pipeline. The processor is signal-connected to the temperature sensor and the differential pressure sensor.

[0008] In some embodiments, the heating device includes: an inner pipe, a steam pipe, an outer pipe, and a steam box, wherein the steam outlet of the steam box is connected to the steam pipe, the outer pipe is sleeved on the outside of the inner pipe, the steam pipe is located between the inner pipe and the outer pipe and is wound around the outer surface of the inner pipe, and the experimental pipeline is embedded inside the inner pipe.

[0009] In some implementations, the experimental piping is a spiral piping.

[0010] In some embodiments, a filtration unit is also included. The filtration unit is connected to the experimental pipeline via an outlet valve. The filtration unit includes a frame, rock slabs, and a pressurizing device. The frame has openings at opposite ends, and rock slabs are slidably installed in both openings of the frame. The rock slabs and the frame enclose a sealed cavity. The outlet valve is connected to the sealed cavity inside the frame. The side of each rock slab closest to the outside of the frame opening is connected to a pressurizing device. The pressurizing device selectively drives the rock slabs to reciprocate along the direction of the frame opening. A plurality of filtration holes are arrayed on the surface of the rock slabs along the direction of the frame opening.

[0011] In some embodiments, an annular plate and an end plate are also included. The annular plate is stacked on the side of the rock slab near the outer side of the frame opening. The outer edge of the annular plate is in close contact with the inner wall of the frame. The end plate is stacked on the side of the annular plate near the outer side of the frame opening. The pressurizing device is connected to the side of the end plate near the outer side of the frame opening. The end plate, the annular plate and the rock slab enclose each other to form a second cavity. The filter hole is connected to the second cavity.

[0012] In some implementations, at least one side of the end plate, the ring plate, and the frame is made of a transparent material.

[0013] In some implementations, the transparent side of the frame is provided with graduations along the opening direction.

[0014] In some embodiments, a waste liquid tank is also included, which is connected to the side of the sealed cavity away from the outlet valve.

[0015] On the other hand, the present invention also provides a method for evaluating the performance of fracturing fluid using the above-mentioned evaluation device, comprising the following steps:

[0016] Step 1: The first plunger pump pumps the fracturing fluid to be tested from the storage tank to the experimental pipeline;

[0017] Step 2: Close the outlet valve and the first plunger pump, and open the first valve, the second valve and the second plunger pump. At the same time, the heating device heats the experimental pipeline.

[0018] Step 3: Temperature sensor and differential pressure sensor detect the temperature of the fracturing fluid entering the experimental pipeline and the pressure of the fracturing fluid entering and exiting the experimental pipeline, respectively. The processor records the temperature data and differential pressure data from the temperature sensor and differential pressure sensor. Based on the recorded temperature data and differential pressure data, the change process of friction of the fracturing fluid as the temperature changes can be calculated.

[0019] In some implementations, step four is also included: shutting off the second plunger pump, opening the outlet valve and the first plunger pump, and delivering the fracturing fluid at a certain temperature after being tested through the experimental pipeline to the filtration unit. The pressurizing device applies the same pressure to the two rock plates according to the target formation stress to simulate the fracturing effect, record the time and fracturing fluid migration data in the simulated fracture, and calculate the filtration parameters.

[0020] The fracturing fluid performance evaluation device of the present invention has the following advantages over the prior art:

[0021] The evaluation device of this invention can heat the fracturing fluid to simulate the gradual increase in fracturing fluid temperature and the gradual change in the module as the bottom layer temperature increases over time. Compared with traditional flat-plate fracture filtration devices, it is closer to the actual situation and the measurement results are more accurate. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a connection diagram of the fracturing fluid performance evaluation device of the present invention;

[0024] Figure 2 This is a schematic diagram of the connection of the experimental pipeline in the fracturing fluid performance evaluation device of the present invention;

[0025] Figure 3This is a cross-sectional view of the filtration unit in the fracturing fluid performance evaluation device of the present invention;

[0026] Figure 4 This is an isometric view of the heating device portion of the fracturing fluid performance evaluation device of the present invention;

[0027] Figure 5 This is a schematic diagram of the structure of the heating device and the experimental pipeline in the fracturing fluid performance evaluation device of the present invention;

[0028] Figure 6 This is a graph showing the relationship between bottom hole temperature and time under different wellhead injection rates obtained before evaluation in Embodiment 1 of the present invention.

[0029] In the diagram: 1-Storage tank, 2-First plunger pump, 3-Check valve, 4-Experimental pipeline, 5-Outlet valve, 6-Second plunger pump, 7-Heating device, 8-Temperature sensor, 9-Differential pressure sensor, 10-Processor, 11-Filtering unit, 12-Waste liquid tank, 13-First valve, 14-Second valve, 71-Inner pipeline, 72-Steam pipe, 73-Outer pipeline, 74-Steam box, 111-Frame, 112-Rock slab, 113-Pressure device, 114-Annular plate, 115-End plate. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0032] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this invention pertain. If any definition stated in this section is contrary to or otherwise inconsistent with a definition stated in a patent, patent application, published patent application, or other publication incorporated herein by reference, the definitions listed here shall prevail over those incorporated herein by reference.

[0035] like Figure 1 As shown, combined with Figure 2-5 The fracturing fluid performance evaluation device of the present invention includes: a storage tank 1, a first plunger pump 2, a one-way valve 3, an experimental pipeline 4, and an outlet valve 5 connected in sequence; it also includes a second plunger pump 6, a heating device 7, a temperature sensor 8, a differential pressure sensor 9, and a processor 10. The outlet of the second plunger pump 6 is connected to the end of the experimental pipeline 4 near the one-way valve 3, and the inlet of the second plunger pump 6 is connected to the end of the experimental pipeline 4 near the outlet valve 5. The second plunger pump 6 and the experimental pipeline 4 are connected in parallel. A first valve 13 is connected to the outlet of the second plunger pump 6, and a second valve 14 is connected to the inlet of the second plunger pump 6. The heating device 7 is sleeved on the outside of the experimental pipeline 4. The sensing end of the temperature sensor 8 is located at the opening of the experimental pipeline 4 near the first plunger pump 2. The two sensing ends of the differential pressure sensor 9 are respectively located at the openings at both ends of the experimental pipeline 4. The processor 10 is signal-connected to the temperature sensor 8 and the differential pressure sensor 9.

[0036] In the above embodiments, the second plunger pump 6 is connected in parallel with the experimental pipeline 4 to form a local circulation pipeline. The fracturing fluid flowing through the experimental pipeline 4 is heated by the heating device 7 to simulate the temperature rise of the fracturing fluid during actual use. The differential pressure sensor 9 can detect the pressure change of the fracturing fluid after flowing through the experimental pipeline 4. Combined with the temperature sensor 8 to detect the temperature of the fracturing fluid flowing into the experimental pipeline 4, the frictional resistance of the fracturing fluid can be calculated with temperature. The processor 10 can record the detection data from the differential pressure sensor 9 and the detection data from the temperature sensor 8 for experimental calculation.

[0037] In some embodiments, the heating device includes: an inner pipe 71, a steam pipe 72, an outer pipe 73, and a steam box 74, wherein the steam box 74 produces steam, the steam outlet of the steam box 74 is connected to the steam pipe 72, the outer pipe 73 is coaxially sleeved on the outside of the inner pipe 71, the steam pipe 72 is located between the inner pipe 71 and the outer pipe 72, the steam pipe 72 is wound around the outer surface of the inner pipe 71, and the experimental pipe 4 is embedded in the inner side of the inner pipe 71.

[0038] In the above embodiments, the steam box 74 produces steam, which is discharged into the steam pipe 72 through the outlet of the steam box 74. The steam pipe 72 is arranged around the outside of the inner pipe 71. The steam pipe 72 heats the inner pipe 71, and the outer pipe 73 protects the steam pipe 72 and retains the heat radiated by the steam pipe 72 to prevent heat loss. The experimental pipeline 4 located in the inner pipe 71 is heated at the same time as the inner pipe 71 heats up.

[0039] In the above embodiments, the two ends of the experimental pipeline 4 are respectively connected to the inner pipeline 71 and the outer pipeline 73, and the connection points are all in close contact with the inner pipeline 71 and the outer pipeline 73. The end of the inner pipeline 71, the steam pipe 72 and the outer pipeline 73 away from the steam box 74 is connected to the atmosphere or to the waste steam collection device.

[0040] In some embodiments, the inner surface of the outer pipe 73 is provided with an insulation layer, which can improve the insulation performance of the outer pipe 73.

[0041] In some embodiments, a protective layer is provided on the outer surface of the outer pipe 73. The protective layer is used to improve the structural strength of the outer pipe 73 and at the same time improve the safety of the heating device 7.

[0042] In some embodiments, experimental pipeline 4 is a spiral pipeline.

[0043] The spiral-shaped experimental pipeline 4 can extend the heating time of the fracturing fluid and improve the heating efficiency.

[0044] In some embodiments, a filtration unit 11 is also included. The filtration unit 11 is connected to the experimental pipeline 4 through an outlet valve 5. The filtration unit 11 includes a frame 111, a rock plate 112, and a pressurizing device 113. The frame 111 has openings at opposite ends. A rock plate 112 is slidably disposed in each of the openings at both ends of the frame 111. The two rock plates 112 and the inner wall of the frame 111 enclose a sealed cavity. The outlet valve 5 is connected to the sealed cavity in the frame 111. The pressurizing device 113 is connected to the side of the two rock plates 112 near the outside of the opening of the frame 111. The pressurizing device 113 selectively drives the rock plate 112 to reciprocate along the opening direction of the frame 111. A plurality of filtration holes are arrayed on the surface of the rock plate 112 along the opening direction of the frame 111.

[0045] In the above embodiments, the filtration unit 11 is used to simulate the stress of the target formation. Dynamic cracks are formed between the two rock plates 112. The pressure of the pressurization device 113 is set according to the pressure of the target formation. When the fracturing fluid flows between the two rock plates 112, under the action of pressure, the filtrate flows from the filtration hole to the outer surface of the rock plate 112. By collecting the filtrate and measuring the outflow of the filtrate, the corresponding filtration parameters can be calculated.

[0046] In some embodiments, the system further includes an annular plate 114 and an end plate 115. The annular plate 114 is stacked on the side of the rock slab 112 near the outer side of the opening of the frame 111. The outer edge of the annular plate 114 is in close contact with the inner wall of the frame 111. The end plate 115 is stacked and fitted against the side of the annular plate 114 near the outer side of the opening of the frame 111. The pressurizing device 113 is connected to the side of the end plate 115 near the outer side of the opening of the frame 111. The pressurizing device 113 drives the end plate 115 to apply pressure and transmits it to the surface of the rock slab 112 through the annular plate 114. The end plate 115, the annular plate 114 and the rock slab 112 enclose each other to form a second cavity. The filter hole communicates with the second cavity.

[0047] In the above embodiments, an end plate 115 and an annular plate 114 are provided to form a cavity for collecting filtrate together with the rock plate 112, which reduces the difficulty of collection and avoids the problem of difficulty in calculating the contact area and stress concentration in the contact part when the pressurizing device 113 directly contacts the rock plate 112. Secondly, the area of ​​the surface of the second cavity in the middle of the annular plate 114 that communicates with the rock plate 112 is easy to calculate.

[0048] In some embodiments, at least one side of the end plate 15, the annular plate 114, and the frame 111 is made of transparent material.

[0049] In the above embodiments, in order to further reduce the difficulty of measuring the volume of the filtrate and to facilitate the observation and recording of the filtrate loss process, at least one side of the frame 111 is made of transparent material. Through the transparent side of the frame 111, the flow pattern of the fracturing fluid between the two rock plates 112 can be directly observed. The transparent annular plate 114 and end plate 115 allow the filtrate loss process to be observed from the opening direction of the frame 111, which is the projection direction of the rock plate 112. Furthermore, the amount of filtrate entering the second cavity can be observed through a straight tube. Given the inner area of ​​the annular plate 114, the volume of the filtrate can be directly calculated by measuring the height of the filtrate in the second cavity.

[0050] In some embodiments, a waste liquid tank 12 is also included, which is connected to the side of the sealed cavity away from the outlet valve 5.

[0051] Waste liquid tank 12 is used to collect the remaining fracturing fluid after measurement.

[0052] The evaluation method of the evaluation device in the above embodiments includes the following steps:

[0053] Step 1: The first plunger pump 2 pumps the fracturing fluid to be tested from the storage tank to the experimental pipeline 4;

[0054] Step 2: Close the outlet valve 5 and the first plunger pump 2, and open the first valve 13, the second valve 14 and the second plunger pump 6. At the same time, the heating device 7 heats the experimental pipeline 4.

[0055] Step 3: Temperature sensor 8 and differential pressure sensor 9 detect the temperature of the fracturing fluid entering the experimental pipeline 4 and the pressure of the fracturing fluid entering and exiting the experimental pipeline 4, respectively. Processor 10 records the temperature data and differential pressure data from temperature sensor 8 and differential pressure sensor 9. Based on the recorded temperature data and differential pressure data, the change process of friction of the fracturing fluid as the temperature changes can be calculated.

[0056] In some embodiments, step four may also be included: turning off the second plunger pump 6, turning on the outlet valve 5 and the first plunger pump 2, delivering the fracturing fluid at a certain temperature after being tested by the experimental pipeline 4 to the filtration unit 11, and the pressurizing device 113 applying the same pressure to the two rock plates 112 according to the target formation stress to simulate the fracturing effect, recording the time and fracturing fluid migration data in the simulated fracture, and calculating the filtration parameters.

[0057] Example 1

[0058] An experiment to evaluate the drag reduction performance of fracturing fluids in high-temperature oil reservoirs:

[0059] Experimental Objective: To clarify the changes in friction of fracturing fluid from the wellbore under the influence of formation temperature during pumping, to evaluate the drag reduction performance of fracturing fluid under formation temperature conditions, and to provide an evaluation method for selecting fracturing fluids for specific reservoir field operations; and to clarify the changes in drag reduction performance of fracturing fluid from the wellbore under different temperature conditions under the influence of formation temperature, and to provide an evaluation method for determining the temperature adaptability range of specific fracturing fluids.

[0060] Experimental parameters: formation depth, low temperature gradient, actual discharge rate, actual pipe diameter, and fracturing fluid type.

[0061] Experimental output parameters: wellbore pressure drop of the experimental fracturing fluid (measured by differential pressure sensor), drag reduction rate of the experimental fracturing fluid (calculated), comparison of drag reduction performance of fracturing fluid under different temperature conditions, change of fracturing fluid friction with time under formation temperature conditions, and comparison of drag reduction performance of fracturing fluid under different temperature conditions.

[0062] Experimental steps:

[0063] Step 1: Obtain geological data of the target reservoir. Based on reservoir depth and low-temperature gradient data, use MATLAB to call the COMSOL kernel to solve for heat transfer in the wellbore and fractures. Combined with production parameters (actual discharge rate, fracturing operation time), obtain the bottom hole temperature variation curve over time, such as... Figure 6 As shown.

[0064] Step 2: Set the heating device in this invention according to the temperature change curve over time, so that the heating process of the heating device is synchronized with the temperature change curve over time. Figure 6 Matching the temperature changes;

[0065] Step 3: Determine the various experimental parameters based on the production data. The displacement is determined based on the Reynolds number formula for non-Newtonian power-law fluids: In the formula: n is the flow index, which is dimensionless; K is the consistency coefficient of fracturing fluid, Pa·sn; v is the fluid velocity; ρ is the fluid density; and d is the pipe diameter.

[0066] The flow velocity inside the pipe conforms to: Where Q is the actual displacement.

[0067] According to the principle of equal Reynolds numbers, we can obtain p and m represent actual parameters and experimental parameters, respectively. The experimental discharge rate can be determined based on the actual discharge rate, actual pipe diameter, and pipe diameter of the experimental pipeline, thereby ensuring that the experimental results are consistent with the actual situation.

[0068] Step 4: Load the prepared fracturing fluid into the storage tank, open the check valve, the first valve and the second valve, close the outlet valve, turn on the first plunger pump, control the flow rate to allow the fracturing fluid to slowly enter the pipeline, wait for the fracturing fluid to fill the loop formed by the spiral pipeline and the pipeline where the second plunger pump is located, and immediately close the first plunger pump and the check valve after the fracturing fluid fills the loop. At this time, the loop becomes a closed loop. Turn on the second plunger pump to make the fracturing fluid circulate in the circulation loop.

[0069] Step 5: Turn on the heating device and heat the fracturing fluid in the experimental pipeline according to the settings in Step 2. Turn on the temperature sensor and differential pressure sensor to record the temperature and differential pressure data in the experimental pipeline in real time and analyze the change of fracturing fluid friction with temperature. After the fracturing fluid rises to the specified temperature and the required temperature and differential pressure data are recorded, turn off the heating device, temperature sensor, differential pressure sensor and second plunger pump.

[0070] Step Six: Repeat the above experimental steps, replacing the displacing fluid with water. Calculate the wellbore drag reduction rate of the fracturing fluid based on the pressure drop generated by the flow of water and fracturing fluid in the experimental pipeline under the same operating conditions. The formula for calculating the wellbore drag reduction rate of the experimental fracturing fluid is as follows:

[0071] In the formula, DR is the drag reduction ratio; ΔP 水 For the pressure drop in the clear water well shaft; ΔP 压裂液 To test the pressure drop of fracturing fluid in the wellbore.

[0072] Example 2

[0073] A method for evaluating the filtration performance of fracturing fluid in high-temperature oil reservoirs

[0074] Experimental objective: To clarify the changes in fracturing fluid friction under formation temperature during the process of fracturing fluid entering the formation from the wellbore under different temperature conditions, to evaluate the drag reduction performance of fracturing fluid under formation temperature conditions, and to provide an evaluation method for screening fracturing fluids for field operations in specific oil reservoirs.

[0075] Experimental parameters: formation depth, geothermal gradient, actual discharge rate, actual pipe diameter, and fracturing fluid type.

[0076] Experimental output parameters: wellbore pressure drop of the experimental fracturing fluid (measured by differential pressure sensor), drag reduction rate of the experimental fracturing fluid (calculated), fracturing fluid filtration volume (liquid volume in the cavity) under different temperature conditions, filtration time, and filtration rate.

[0077] Experimental steps:

[0078] Step 1: Fill the prepared fracturing fluid into the storage tank, open the check valve, the first valve, and the second valve, and close the outlet valve. Turn on the first plunger pump and control the flow rate to allow the fracturing fluid to slowly enter the pipeline. Wait for the fracturing fluid to fill the loop consisting of the experimental pipeline and the pipeline containing the second plunger pump. Once the loop is full, immediately close the first plunger pump and the check valve. At this point, the loop is closed. Turn on the second plunger pump to circulate the fracturing fluid within the loop.

[0079] Step 2: Turn on the heating device, set the temperature as required, and heat the fracturing fluid circulating in the experimental pipeline; turn on the temperature sensor to record the temperature data of the circulating pipeline in real time. Once the fracturing fluid reaches the specified temperature, turn off the heating device.

[0080] Step 3: Install a rock slab with lithology similar to the target formation in advance, or prepare a rock slab from a natural core of the target formation. Set up a pressurization device according to the in-situ stress of the target formation to make the dynamic fractures more closely resemble the conditions of the target formation. Open the outlet valve, close the first and second valves, and open the first plunger pump and check valve to allow fracturing fluid to enter the filtration unit. Record the filtration time from the moment the fracturing fluid enters the filtration unit. After a portion of the filtrate has been collected in the second chamber, close the first plunger pump and the outlet valve, stop recording the time, and read the volume of fracturing fluid collected in the second chamber of the filtration unit. Calculate the filtration rate using the following formula and record the total filtration volume. After the experiment, drain the fracturing fluid from the device and chambers to prevent residual liquid from affecting the next experiment. Filtration rate calculation formula:

[0081] Where: V - filtration volume, m 3 t - filtration time, min.

[0082] The evaluation device of this invention can reflect the process of fracturing fluid gradually increasing in temperature and frictional resistance as the bottom layer temperature increases and time passes during actual fracturing. Compared with the filtration loss of fracturing fluid during the steady flow of fracturing fluid in the fracture in the traditional flat plate fracture filtration device, the filtration unit simulates the fracturing fluid filtration loss during the process of fracture opening under pressure, which is closer to the actual situation. Therefore, the filtration property of fracturing fluid can be measured more accurately.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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. A fracturing fluid performance evaluation device, characterized in that, include: The system comprises, in sequence, a storage tank, a first plunger pump, a check valve, an experimental pipeline, and an outlet valve. It also includes a second plunger pump, a heating device, a temperature sensor, a differential pressure sensor, and a processor. The outlet of the second plunger pump is connected to the end of the experimental pipeline near the check valve, and the inlet of the second plunger pump is connected to the end of the experimental pipeline near the outlet valve. A first valve is located at the outlet of the second plunger pump, and a second valve is located at the inlet of the second plunger pump. A heating device is fitted around the outside of the experimental pipeline. The sensing end of the temperature sensor is located at the opening of the experimental pipeline near the first plunger pump. The two sensing ends of the differential pressure sensor are located at the openings at both ends of the experimental pipeline. The processor is connected to the temperature sensor and the differential pressure sensor. The system also includes a filtration unit, which is connected to the experimental pipeline via the outlet valve. The filtration unit includes a frame, a rock slab, and a pressurizing device. The frame has openings at opposite ends, and each opening contains a sliding component. The system includes a rock slab and a frame that enclose a sealed cavity. A water outlet valve communicates with this sealed cavity within the frame. Each rock slab has a pressurizing device connected to its outer side near the frame opening. The pressurizing device selectively drives the rock slab to reciprocate along the frame opening direction. The rock slab surface has several filter holes arranged in an array along the frame opening direction. The system also includes an annular plate and end plates. The annular plate is stacked on the rock slab side near the frame opening, with its outer edge sealed to the inner wall of the frame. The end plates are stacked on the annular plate side near the frame opening. The pressurizing device is connected to the end plate side near the frame opening. The pressurizing device drives the end plate to apply pressure and transmits the pressure to the rock slab surface through the annular plate. The end plates, annular plates, and rock slabs enclose a second cavity for collecting filtrate. The filter holes communicate with this second cavity. At least one side of the end plates, annular plates, and frame is made of transparent material. The transparent side of the frame has graduations along the opening direction.

2. The fracturing fluid performance evaluation device as described in claim 1, characterized in that, The heating device includes an inner pipe, a steam pipe, an outer pipe, and a steam box. The steam outlet of the steam box is connected to the steam pipe. The outer pipe is sleeved on the outside of the inner pipe. The steam pipe is located between the inner pipe and the outer pipe and is wrapped around the outer surface of the inner pipe. The experimental pipeline is embedded inside the inner pipe.

3. The fracturing fluid performance evaluation device as described in claim 1, characterized in that, The experimental pipeline is a spiral pipeline.

4. The fracturing fluid performance evaluation device as described in claim 1, characterized in that, It also includes a waste liquid tank, which is connected to the side of the sealed cavity away from the outlet valve.

5. A method for evaluating the performance of fracturing fluid, characterized in that, The evaluation is performed using the evaluation device described in any one of claims 1-4, comprising the following steps: Step 1: A first plunger pump pumps the fracturing fluid to be tested from the storage tank to the experimental pipeline; Step 2: The outlet valve and the first plunger pump are closed, and the first valve, the second valve, and the second plunger pump are opened, while the heating device heats the experimental pipeline; Step 3: Temperature sensors and differential pressure sensors detect the temperature of the fracturing fluid entering the experimental pipeline and the pressure of the fracturing fluid entering and exiting the experimental pipeline, respectively. The processor records the temperature data and differential pressure data from the temperature sensors and differential pressure sensors, and calculates the change in friction of the fracturing fluid as the temperature changes based on the recorded temperature data and differential pressure data; Step 4: The second plunger pump is closed, and the outlet valve and the first plunger pump are opened. The fracturing fluid at a certain temperature after being tested in the experimental pipeline is delivered to the filtration unit. The pressurization device applies the same pressure to the two rock plates according to the target formation stress, simulating the fracture filtration effect and recording the filtration time; After the filtrate is collected in the second chamber, the volume of the filtrate is calculated by measuring the height of the filtrate in the second chamber, given the known inner area of ​​the annular plate. The filtrate loss rate is then determined based on the filtrate loss volume and the filtrate loss time, and is used as the filtrate loss parameter of the fracturing fluid.

6. The fracturing fluid performance evaluation method as described in claim 5, characterized in that, Before fracturing fluid is delivered to the filtration unit, a rock plate with lithology similar to that of the target formation is installed in the filtration unit, or a rock plate made from the natural rock core of the target formation is installed, and a pressurization device is set according to the geostress of the target formation.

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