Method and device for evaluating low-temperature fracturing fluid

Abstract

The invention discloses a low-temperature fracturing fluid evaluation method and device, and belongs to the technical field of hydraulic fracturing in oil exploitation, and the method comprises the following steps: step 1, after various components and proportions of fracturing fluid are prepared, the fracturing fluid for experiments is formed under the action of a stirring motor in a fluid preparation tank; 2, the fracturing fluid is input into a double-layer full-visual fracturing fluid conveying pipe under the hydraulic action of a screw pump, and under the action of low-temperature circulating cooling liquid of the double-layer full-visual fracturing fluid conveying pipe and the action of pipe wall friction resistance and the like, the pressure difference, fluid dynamic viscosity and other characteristics of the fracturing fluid can be changed; 3, the fracturing fluid enters a filter, a solid phase is filtered out, and the mass ratio of all the components is researched. The invention further discloses a low-temperature fracturing fluid evaluation device. According to the technical scheme, a reliable basis is provided for fracturing construction design.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic fracturing in petroleum exploitation and relates to a method and a device for evaluating low-temperature fracturing fluid. Background Art

[0002] Tight sandstone gas reservoirs usually have the characteristics of low porosity and low permeability, and fracturing is often used to release production capacity. Due to its low porosity and low permeability characteristics, the fracturing fluid needs to have low filtration damage after entering the formation and be easy to flow back to reduce damage to the reservoir. For some shallow buried reservoirs, higher requirements are placed on the performance of the fracturing fluid. The shallow buried reservoir has low temperature and low pressure, and the fracturing fluid needs to be able to quickly break the gel and flow back at low temperature to reduce the retention of the fracturing fluid in the formation.

[0003] In addition, during the transportation of fracturing fluid, the performance of the fracturing fluid may decrease due to the cold winter.

[0004] Therefore, in order to develop a low-temperature environment that may occur during transportation and fracturing, a fracturing fluid evaluation device for low-temperature fracturing was developed by optimizing guar gum and supporting additives. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to solve the above technical problems and provide a low-temperature fracturing fluid evaluation method and device, so that in a low-temperature environment, by continuously adjusting the ratio of silica gel and supporting additives, a fracturing fluid evaluation device for low-temperature fracturing fluid can be developed to provide a reliable basis for fracturing construction design.

[0006] In order to solve the above technical problems, on the one hand, an embodiment of the present invention provides a method for evaluating low-temperature fracturing fluid, comprising the following steps:

[0007] Step 1: After the components and proportions of the fracturing fluid are prepared, a stirring motor is used in a liquid preparation tank to form an experimental fracturing fluid;

[0008] Step 2: The fracturing fluid is input into the double-layer fully visible fracturing fluid delivery pipe under the hydraulic action of the screw pump. Under the action of the low-temperature circulating coolant and the friction resistance of the pipe wall of the double-layer fully visible fracturing fluid delivery pipe, the pressure difference and fluid dynamic viscosity characteristics of the fracturing fluid will change;

[0009] Step 3: The fracturing fluid then enters the filter to filter out the solid phase and study the mass proportion of each component.

[0010] Furthermore, in step 2, the cooling liquid circulation process is that the low-temperature constant temperature tank is connected to the cooling liquid circulation passage in the double-layer fully visible fracturing fluid delivery pipe to continuously circulate the low-temperature cooling liquid.

[0011] Furthermore, the fracturing fluid enters the double-layer fully visible fracturing fluid delivery pipe and begins to cool down under the action of the coolant.

[0012] Furthermore, the mass proportion of each component is studied to evaluate the implementation effect of different fracturing fluid compositions, proportions and drag reducers.

[0013] Furthermore, the research content also includes the characteristic changes of pressure drop, friction gradient, shear rate, shear stress, and fluid dynamic viscosity.

[0014] On the other hand, an embodiment of the present invention further provides a low-temperature fracturing fluid evaluation device, wherein a stirring motor is installed on a liquid distribution tank and fixed with four screws; a water outlet pipeline is connected to the bottom of the liquid distribution tank, a water outlet valve is connected to the middle of the water outlet pipeline, and both the front and rear are connected by threads; a screw pump and a water outlet pipeline are connected by threads, and the screw pump is placed horizontally; the other end of the screw pump is connected to a tee, and the valve at the discharge port is connected to the tee by threads; a safety valve and an inlet pressure gauge are both installed on the water pipe by threads; the inlet and outlet of the double-layer fully visible fracturing fluid delivery pipe are respectively connected by threads. The high and low temperature constant temperature tank uses a pipeline to transport the heat transfer medium to the outer layer of the double-layer fully visible fracturing fluid delivery pipe, and the pipeline and the outer layer of the double-layer fully visible fracturing fluid delivery pipe are connected by threads; the outlet of the double-layer fully visible fracturing fluid delivery pipe is connected to the filter by a metal pipeline, the middle of the pipeline is connected to the outlet pressure gauge by threads, and the end is connected to a tee; one pipeline of the tee is connected to a metal pipe, and the metal pipe is suspended on the upper part of the liquid distribution tank and penetrates into the tank; the filter is connected to the flow meter by threads, and the outlet of the flow meter is connected to the metal pipe suspended on the upper part of the liquid distribution tank by threads.

[0015] Furthermore, the double-layer fully visible fracturing fluid delivery pipe includes a coolant circulation passage, a fully visible coolant jacket layer, an internal fracturing fluid delivery channel, an inner layer of high-pressure resistant fully visible glass tube, and differential pressure sensors at the inlet and outlet of the fracturing fluid. The values ​​measured by the differential pressure sensor are displayed by a pressure measuring digital display instrument. The differential pressure sensor is fixed to the fracturing fluid inlet and outlet with threads at both ends of the double-layer fully visible fracturing fluid delivery pipe; the coolant inlet and coolant outlet are at both ends of the double-layer fully visible fracturing fluid delivery pipe, which are channels between the fully visible coolant interlayer and the external pipeline, and are internal threads for connecting the coolant delivery pipe; the internal fracturing fluid delivery channel is composed of two inner layer of high-pressure resistant fully visible glass tubes; the fully visible coolant interlayer and the inner layer of high-pressure resistant fully visible glass tube are installed at both ends in the metal slot, and the metal slot is fixed by a metal rod, and the metal rod is connected to the metal slot with a thread, and the connection tightness of the fully visible coolant interlayer, the inner layer of high-pressure resistant fully visible glass tube and the metal slot is adjusted by adjusting the thread.

[0016] Furthermore, the coolant circulation passage in the double-layer fully visible fracturing fluid delivery pipe is only connected to the low-temperature constant temperature tank, and the low-temperature coolant is continuously circulated.

[0017] Furthermore, the inlet and outlet of the double-layer fully visible fracturing fluid delivery pipe are designed with differential pressure sensor pressure measurement interfaces, which can be connected to the differential pressure sensor to measure the pressure difference between the inlet and outlet of the pipeline and calculate the friction resistance of the fracturing fluid in the delivery pipeline.

[0018] Furthermore, flanges on both sides of the inner pipe of the double-layer fully visible fracturing fluid delivery pipe are connected by quick-opening joints and connected by a high-pressure hose.

[0019] Furthermore, the double-layer fully visible fracturing fluid delivery pipe is designed as a double-layer fully visible structure, with a pressure-resistant fully visible fracturing fluid delivery channel inside and a transparent liquid circulation jacket layer outside. Low-temperature coolant can be circulated into the circulation jacket layer through a low-temperature constant temperature tank to simulate a low-temperature environment. The flow process of the fracturing fluid carrying the proppant can be observed in real time, and real-time data collection, analysis, and processing can be achieved.

[0020] Furthermore, in the fracturing fluid delivery pipeline and the flip bracket, the fracturing fluid delivery pipe is installed with a flip bracket and equipped with bearings, etc., to achieve 0-90° flipping of the fracturing fluid delivery pipe, and to simulate the state changes of different fracturing fluids in different delivery directions. The fracturing fluid delivery pipe is connected to the flip bracket through a bearing, and the upper part of the flip bracket is welded to the bearing seat.

[0021] The above technical solution of the embodiment of the present invention has the following beneficial technical effects:

[0022] The present invention studies the flow state of fracturing fluid in a low temperature environment, observes the low temperature resistance of the fracturing fluid, optimizes the formula of the fracturing fluid and additives, measures the friction resistance of fracturing fluids with different displacements and evaluates the use effect of the drag reducer, providing a reliable basis for fracturing construction design.

[0023] The technical solution of the present invention can simulate the working state of the fracturing fluid in the conveying pipelines at different angles such as horizontal and vertical under the low-temperature conveying environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure shows a schematic diagram of the process of the low-temperature fracturing fluid evaluation device of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of the fracturing fluid delivery pipeline of the present invention;

[0026] Figure 3 It is a schematic diagram of the fracturing fluid delivery pipeline and the flip support, wherein A is a straight view and B is a side view. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0028] like Figure 1 As shown in the work flow diagram of the low-temperature fracturing fluid evaluation device, the characteristic changes of pressure drop, friction gradient, shear rate, shear stress, fluid dynamic viscosity, etc. of a certain component of fracturing fluid under a low-temperature transportation environment are studied.

[0029] The working process of the whole device is as follows: after the components and proportions of the fracturing fluid are prepared, the experimental fracturing fluid is formed under the action of the stirring motor 2 in the liquid preparation tank 1. The fracturing fluid is input into the double-layer fully visible fracturing fluid delivery pipe 5 through the high and low temperature constant temperature tank 4 under the hydraulic action of the screw pump 3. Under the action of the low-temperature circulating coolant of the double-layer fully visible fracturing fluid delivery pipe 5 and the friction resistance of the pipe wall, the pressure difference, fluid dynamic viscosity and other characteristics of the fracturing fluid will change. The fracturing fluid then enters the filter 6 to filter out the solid phase to evaluate the implementation effects of different fracturing fluid components, proportions and drag reducers. The double-layer fully visible fracturing fluid delivery pipe 5 is provided with a differential pressure sensor 7, and the delivery pipeline of the double-layer fully visible fracturing fluid delivery pipe 5 is provided with an outlet differential pressure sensor pressure measuring interface 9 and an inlet differential pressure sensor pressure measuring interface 10, and the inlet differential pressure sensor pressure measuring interface 10 is connected to the safety valve 11, the filter 6 is provided with a flow meter 8, and the screw pump 3 is provided with a discharge valve 12.

[0030] like Figure 2 As shown, the double-layer fully visible fracturing fluid delivery pipe 5 includes a coolant inlet 20, a coolant outlet 21, a coolant circulation passage 13, a fully visible coolant jacket layer 14, an internal fracturing fluid delivery channel 15, an inner layer high-pressure resistant fully visible glass tube 16, a fracturing fluid inlet 17 and a fracturing fluid outlet 18. The fracturing fluid inlet and the fracturing fluid outlet are provided with a differential pressure sensor interface 19, and the value measured by the differential pressure sensor is displayed by a pressure measuring digital display instrument.

[0031] The coolant circulation passage in the double-layer fully visible fracturing fluid delivery pipe is only connected to the low-temperature constant temperature tank, and the low-temperature coolant is continuously circulated.

[0032] The inlet and outlet of the fracturing fluid delivery pipe of the double-layer fully visible fracturing fluid delivery pipe are both designed with differential pressure sensor pressure measurement interfaces, which can be connected to the differential pressure sensor to measure the pressure difference between the inlet and outlet of the pipeline and calculate the friction resistance of the fracturing fluid in the delivery pipeline.

[0033] The flanges on both sides of the inner pipe of the double-layer fully visible fracturing fluid delivery pipe are connected by quick-open joints and can be connected by high-pressure hoses, so as to be easy to rotate on the flip bracket.

[0034] The low-temperature constant temperature bath is equipped with a circulation pump which can achieve a lower circulation temperature while ensuring the temperature control accuracy.

[0035] The double-layer fully visible fracturing fluid delivery pipe is designed as a double-layer fully visible structure, with a pressure-resistant fully visible fracturing fluid delivery channel inside and a transparent liquid circulation jacket layer outside. Low-temperature coolant can be circulated into the circulation jacket layer through a low-temperature constant temperature tank to simulate a low-temperature environment. The flow process of the fracturing fluid carrying the proppant can be observed in real time, and real-time data collection, analysis, and processing can be achieved.

[0036] Fracturing fluid delivery pipeline and flip support Figure 3 As shown, the fracturing fluid delivery pipe is installed with a flip bracket and equipped with bearings, etc., so that the fracturing fluid delivery pipe can be flipped 0-90 degrees, and the state changes of different fracturing fluids in different delivery directions can be simulated.

[0037] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for evaluating low temperature fracturing fluid, characterized in that: The steps include: Step 1: After the components and proportions of the fracturing fluid are prepared, a stirring motor is used in a liquid preparation tank to form an experimental fracturing fluid; Step 2: The fracturing fluid is input into the double-layer fully visible fracturing fluid delivery pipe under the hydraulic action of the screw pump. Under the action of the low-temperature circulating coolant and the friction resistance of the pipe wall of the double-layer fully visible fracturing fluid delivery pipe, the pressure difference and fluid dynamic viscosity characteristics of the fracturing fluid will change; Step 3: The fracturing fluid then enters the filter to filter out the solid phase and study the mass proportion of each component.

2. The low temperature fracturing fluid evaluation method according to claim 1, characterized in that: In step 2, the coolant circulation process is that the low-temperature constant temperature tank is connected to the coolant circulation passage in the double-layer fully visible fracturing fluid delivery pipe to continuously circulate the low-temperature coolant.

3. The low temperature fracturing fluid evaluation method according to claim 1, characterized in that: In step 2, the fracturing fluid enters the double-layer fully visible fracturing fluid delivery pipe and begins to cool down under the action of the coolant.

4. The low temperature fracturing fluid evaluation method according to claim 1, characterized in that: In step 3, the mass proportion of each component is studied to evaluate the implementation effect of different fracturing fluid compositions, proportions and drag reducers.

5. The low temperature fracturing fluid evaluation method according to claim 1, characterized in that: In step 3, the research also includes changes in the characteristics of pressure drop, friction gradient, shear rate, shear stress, and fluid dynamic viscosity.

6. A low-temperature fracturing fluid evaluation device for implementing the method described in any one of claims 1 to 5, characterized in that: include: The stirring motor is installed on the liquid distribution tank and fixed with four screws; the water outlet pipeline is connected to the bottom of the liquid distribution tank, and the water outlet valve is connected to the middle of the water outlet pipeline, and the front and back are connected by threads; the screw pump and the water outlet pipeline are connected by threads, and the screw pump is placed horizontally; the other end of the screw pump is connected to the tee, and the valve of the discharge port is connected to the tee by threads; the safety valve and the inlet pressure gauge are both installed on the water pipe by threads; the inlet and outlet of the double-layer fully visible fracturing fluid delivery pipe are respectively connected to the two ends of the differential pressure sensor by threads; the high and low temperature constant temperature tank uses a pipeline to transport the heat transfer medium to the outer layer of the double-layer fully visible fracturing fluid delivery pipe, and the pipeline and the outer layer of the double-layer fully visible fracturing fluid delivery pipe are connected by threads; The outlet of the double-layer fully visible fracturing fluid delivery pipe is connected to the filter with a metal pipe, the middle of the pipe is connected to the outlet pressure gauge with a thread, and the end is connected to a tee; one pipeline of the tee is connected to a metal pipe, the metal pipe is suspended on the upper part of the liquid distribution tank and extends into the tank; the filter is connected to the flow meter with a thread, and the outlet of the flow meter is connected to the metal pipe suspended on the upper part of the liquid distribution tank with a thread.

7. The low temperature fracturing fluid evaluation device according to claim 6, characterized in that: The double-layer fully visible fracturing fluid delivery pipe comprises a coolant circulation passage, a fully visible coolant jacket layer, an internal fracturing fluid delivery passage, an inner layer high-pressure resistant fully visible glass tube, and differential pressure sensors at the inlet and outlet of the fracturing fluid. The values ​​measured by the differential pressure sensor are displayed by a pressure measuring digital display instrument. The differential pressure sensor is fixed on the fracturing fluid inlet and the fracturing fluid outlet with threads at both ends of the double-layer fully visible fracturing fluid delivery pipe; the coolant inlet and the coolant outlet are at both ends of the double-layer fully visible fracturing fluid delivery pipe, which are passages between the fully visible coolant interlayer and the external pipeline, and are internal threads for connecting the coolant delivery pipe; the internal fracturing fluid delivery passage is composed of two inner layer high-pressure resistant fully visible glass tubes; the fully visible coolant interlayer and the inner layer high-pressure resistant fully visible glass tube are installed at both ends in metal slots, the metal slots are fixed by metal rods, the metal rods are connected to the metal slots with threads, and the connection tightness of the fully visible coolant interlayer, the inner layer high-pressure resistant fully visible glass tube and the metal slots is adjusted by adjusting the threads.

8. The low temperature fracturing fluid evaluation device according to claim 6, characterized in that: The coolant circulation passage in the double-layer fully visible fracturing fluid delivery pipe is only connected to the low-temperature constant temperature tank, and the low-temperature coolant is continuously circulated.

9. The low temperature fracturing fluid evaluation device according to claim 6, characterized in that: The inlet and outlet of the fracturing fluid delivery pipe of the double-layer fully visible fracturing fluid delivery pipe are both designed with differential pressure sensor pressure measurement interfaces, which can be connected to the differential pressure sensor to measure the pressure difference between the inlet and outlet of the pipeline and calculate the friction resistance of the fracturing fluid in the delivery pipeline.

10. The low temperature fracturing fluid evaluation device according to claim 6, characterized in that: The flanges on both sides of the inner pipe of the double-layer fully visible fracturing fluid delivery pipe are connected by a quick-open joint and connected by a high-pressure hose.

11. The low temperature fracturing fluid evaluation device according to claim 6, characterized in that: The double-layer fully visible fracturing fluid delivery pipe is designed as a double-layer fully visible structure, with a pressure-resistant fully visible fracturing fluid delivery channel inside and a transparent liquid circulation jacket layer outside. Low-temperature coolant is circulated into the circulation jacket layer through a low-temperature constant temperature tank to simulate a low-temperature environment, and the flow process of the fracturing fluid carrying the proppant is observed in real time, while realizing real-time data collection, analysis, and processing.

12. The low temperature fracturing fluid evaluation device according to claim 6, characterized in that: In the fracturing fluid delivery pipeline and the flip bracket, the fracturing fluid delivery pipe is installed with a flip bracket and equipped with bearings to achieve 0-90° flipping of the fracturing fluid delivery pipe, thereby simulating the state changes of different fracturing fluids in different delivery directions. The fracturing fluid delivery pipe is connected to the flip bracket through a bearing, and the upper part of the flip bracket is welded to the bearing seat.

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