Visualization experimental device and method for monitoring the effect of multi-cluster fracturing in horizontal wells based on tracers

Abstract

The present invention discloses a visualization experimental device and method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers. The visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers comprises a preset fracture module, a pumping system and a flowback system. The preset fracture module comprises a first module, a second module and a third module. The first module, the second module and the third module all comprise a transparent block, a sandy film and a top cover plate. The transparent block comprises a first connecting block and a second connecting block spliced ​​together. The first connecting block and the second connecting block respectively have a first splicing surface and a second splicing surface. The top cover plate is covered on the top of the first connecting block and the second connecting block and is sealed and fixed with the first connecting block and the second connecting block. The tops of the transparent blocks of the first module, the second module and the third module are respectively provided with main seam structures.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field exploitation, and in particular to a visualization experimental device and method for monitoring the effect of staged multi-cluster fracturing of a horizontal well based on a tracer. Background Art

[0002] Hydraulic fracturing technology is the key technology for the development of unconventional oil and gas fields at home and abroad. Fracturing crack monitoring and post-fracturing evaluation can provide effective guidance for subsequent development, thereby improving the overall development effect of oil and gas fields. Therefore, low-cost and reliable fracturing monitoring methods are of great significance to ensuring the production capacity of oil and gas fields.

[0003] At present, the main technical methods for fracturing monitoring include microseismic monitoring technology, output profile logging technology, distributed fiber optic monitoring technology, and fracturing tracer monitoring technology. The microseismic monitoring technology has a high degree of technological maturity and has been widely used in the field. However, due to the large ground noise during the fracturing process, the monitoring accuracy of this method is limited. The output profile logging technology is also an early and mature technology for evaluating the production capacity of each section of horizontal well segmented fracturing. However, the logging instrument is greatly affected by the well inclination and multiphase flow in the wellbore, and it is difficult to meet the requirements of dynamic monitoring of fracturing in highly inclined wells. Distributed fiber optic monitoring can accurately characterize the crack size and width changes of fracturing crack closure, but it has high requirements for wellbore conditions and is expensive, so its field application is limited.

[0004] Tracer fracturing monitoring technology has shown good application prospects in fracture monitoring due to its advantages of small tracer dosage, low cost, easy detection, recyclable and accurate results. However, due to the lack of large-scale physical model experimental devices that can simultaneously consider the migration and flowback laws of tracers and proppants, theoretical research on tracer fracturing monitoring technology at home and abroad is all carried out through numerical simulation. The reliability of the results lacks sufficient physical simulation support and cannot provide reliable guidance for on-site fracturing monitoring.

[0005] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0006] The main purpose of the present invention is to provide a visual experimental device and method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, aiming to solve or partially solve the above problems.

[0007] To achieve the above object, the present invention provides a visual experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, comprising:

[0008] A pre-set crack module, comprising a first module, a second module and a third module, wherein the first module, the second module and the third module all comprise a transparent block, a sandy film and a top cover plate, wherein the transparent block comprises a first connecting block and a second connecting block spliced ​​together, wherein the first connecting block and the second connecting block respectively have a first splicing surface and a second splicing surface, wherein the top cover plate is covered on the top of the first connecting block and the second connecting block and is sealed and fixed with the first connecting block and the second connecting block, wherein the tops of the transparent blocks of the first module, the second module and the third module are respectively provided with a main seam structure, wherein the transparent blocks of the second module and the third module are respectively provided with a first-level branch seam and are respectively connected to the main seam structure corresponding thereto, wherein the transparent block of the third module is provided with a second-level branch seam and is connected to the first-level branch seam corresponding thereto, wherein the total volume of the crack structures on the first module, the second module and the third module are the same, wherein the first splicing surface and the second splicing surface of the first module, the second module and the third module respectively define their main seam structures, and the first splicing surface and the second splicing surface are respectively provided with a sandy film;

[0009] A pumping system, connected to one side of the main fracture structure of the first module, the second module and the third module respectively, for pumping a fracturing fluid containing a tracer into the fractures of the first module, the second module and the third module respectively;

[0010] A flowback system includes a flowback pump, a temporary liquid storage pipe and a filtration channel arranged above the top cover plate. The first module, the second module and the third module are all connected with the temporary liquid storage pipe. The temporary liquid storage pipes on the first module, the second module and the third module are respectively communicated with the cracks thereon. The filtration channels on the first module, the second module and the third module are respectively arranged in the first module, the second module and the third module and extend to the splicing surface. The filtration channels on the first module, the second module and the third module are respectively communicated with the temporary liquid storage pipes on the first module, the second module and the third module. The flowback pump is respectively connected with the temporary liquid storage pipes on the first module, the second module and the third module.

[0011] Preferably, in the visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, the pumping system includes a liquid distribution tank, a delivery pump, a first pipeline, the second pipeline, and a third pipeline, the delivery pump includes an inlet, a first outlet, a second outlet, and a third outlet, the liquid distribution tank is connected to the inlet, and the first outlet, the second outlet, and the third outlet are connected to the main seam structures of the first module, the second module, and the third module through the first pipeline, the second pipeline, and the third pipeline respectively;

[0012] The first outlet, the second outlet, and the third outlet are respectively connected to a first valve, a second valve, and a third valve, and the first valve, the second valve, and the third valve are respectively used to control the opening or closing of the first outlet, the second outlet, and the third outlet.

[0013] Preferably, in the visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, the first pipeline, the second pipeline, and the third pipeline are respectively provided with a first drainage port, a second drainage port, and a third drainage port;

[0014] The first liquid discharge port, the second liquid discharge port, and the third liquid discharge port are respectively connected to a fourth valve, a fifth valve, and a sixth valve, and the fourth valve, the fifth valve, and the sixth valve are respectively used to control the opening or closing of the first liquid discharge port, the second liquid discharge port, and the third liquid discharge port.

[0015] Preferably, in the visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, the pumping system further comprises a fourth pipeline, the fourth pipeline is connected to the first pipeline, the second pipeline, and the third pipeline respectively, and the fourth pipeline is provided with a fourth drainage port;

[0016] The connection between the fourth pipeline and the first pipeline is connected to a seventh valve for controlling whether they are connected, the connection between the fourth pipeline and the second pipeline is connected to an eighth valve for controlling whether they are connected, and the connection between the fourth pipeline and the third pipeline is connected to a ninth valve for controlling whether they are connected.

[0017] Preferably, in the visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, the first pipeline, the second pipeline, and the third pipeline are respectively provided with slits, and the first pipeline, the second pipeline, and the third pipeline are respectively connected to the main slit structures of the first module, the second module, and the third module through the slits.

[0018] Preferably, in the visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, the temporary liquid storage pipeline has a first end connected to the filtration channel, and a second end opposite to the first end, and the inner diameter of the first end is larger than the inner diameter of the second end.

[0019] In order to achieve the above object, the present invention also provides a visualization experimental method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers. The experimental method uses the above experimental device to conduct experiments. The experimental method includes:

[0020] Pumping the fracturing fluid mixed with the tracer and the proppant into the first module, the second module, and the third module respectively through the pumping system, so that part of the fracturing fluid enters the filtration pores through the sandy membranes, and enters the corresponding temporary liquid storage pipeline through the filtration pores, and the sandy membranes on the first splicing surface and the second splicing surface restrict the proppant from entering the filtration pores;

[0021] Start the flowback pump to pump out the fracturing fluid in the temporary fluid storage pipeline;

[0022] According to whether the types of tracers injected into the first module, the second module, and the third module are the same, samples are taken at the corresponding drainage ports to detect the tracer concentration, and tracer flowback characteristic curves under different fracture type conditions are drawn.

[0023] Preferably, in the visualization experimental method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, the concentration of tracers is detected by sampling at corresponding drainage ports according to whether the types of tracers injected into the first module, the second module, and the third module are the same, and tracer flowback characteristic curves under different fracture type conditions are drawn, including:

[0024] When the tracer types injected into the first module, the second module, and the third module are of the same type, the fourth valve, the fifth valve, and the sixth valve are opened to discharge the return fluid from the first drain port, the second drain port, and the third drain port. Samples are taken from the first drain port, the second drain port, and the third drain port to detect the tracer concentration, and tracer return characteristic curves under different fracture type conditions are drawn.

[0025] Preferably, in the visualization experimental method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers, the concentration of tracers is detected by sampling at corresponding drainage ports according to whether the types of tracers injected into the first module, the second module, and the third module are the same, and tracer flowback characteristic curves under different fracture type conditions are drawn, including:

[0026] When the types of tracers injected into the first module, the second module, and the third module are different, the seventh valve, the eighth valve, and the ninth valve are opened to discharge the return fluid from the fourth drainage port. Samples are taken at the fourth drainage port to detect the concentrations of various tracers, and tracer return characteristic curves under different fracture type conditions are drawn.

[0027] The present invention has at least the following beneficial effects:

[0028] The present invention provides a visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers. The preset fracture module includes a first module, a second module and a third module. The first module, the second module and the third module all include a transparent block, a sandy film and a top cover plate. The transparent block includes a first connecting block and a second connecting block spliced ​​together. The first connecting block and the second connecting block respectively have a first splicing surface and a second splicing surface. The top cover plate is covered on the top of the first connecting block and the second connecting block and is sealed and fixed with the first connecting block and the second connecting block. The tops of the transparent blocks of the first module, the second module and the third module are respectively provided with main seam structures. The transparent blocks of the second module and the third module are respectively provided with first-level branch seams and are respectively connected to the main seam structures corresponding to them. The transparent block of the third module is provided with second-level branch seams and is connected to the first-level branch seams corresponding to them. The total volume of the fracture structures on the first module, the second module and the third module is the same. The first splicing surface and the second splicing surface of the first module, the second module and the third module respectively define their main seam structures. The first splicing surface and the second joint surface are respectively affixed with a sandy film; the pumping system is respectively connected to one side of the main seam structure of the first module, the second module and the third module, and is used to pump the fracturing fluid containing the tracer into the cracks of the first module, the second module and the third module respectively; the backflow system includes a backflow pump, a temporary liquid storage pipeline arranged above the top cover plate, and a filtration channel, the first module, the second module, and the third module are all connected to the temporary liquid storage pipeline, the temporary liquid storage pipelines on the first module, the second module, and the third module are respectively communicated with the cracks thereon, the filtration channels on the first module, the second module, and the third module are respectively arranged in the first module, the second module, and the third module and extend to the joint surface, the filtration channels on the first module, the second module, and the third module are respectively communicated with the temporary liquid storage pipelines on the first module, the second module, and the third module, and the backflow pump is respectively connected to the temporary liquid storage pipelines on the first module, the second module, and the third module, so as to provide a large-scale physical model experimental device that simultaneously considers the migration-backflow law of the tracer and the proppant.

[0029] Furthermore, in order to compare the tracer flowback characteristic curves under different types of fractures, the pumping parameters of the pumping system, such as liquid volume, displacement, sand adding method, sand volume, and sand ratio, must be kept consistent during the three pumping stages. After the pumping stage of the flowback system is completed, the flowback pump is turned on to pump out the fracturing fluid in the temporary liquid storage pipeline through the filtration channel. Depending on whether the types of tracers injected into the first module, the second module, and the third module are the same, samples are taken regularly at the corresponding discharge ports to detect the tracer concentration, and tracer flowback characteristic curves under different fracture types are drawn, thereby solving the problems mentioned in the background technology.

[0030] Furthermore, in the flowback stage, when the tracers injected into the first module, the second module and the third module are of the same type, in order to avoid confusion, the fourth valve, the fifth valve and the sixth valve are opened, and the flowback fluid is discharged from the first drain port, the second drain port and the third drain port respectively. The fourth drain port is located on the fourth pipeline, and the fourth pipeline is connected to the first pipeline, the second pipeline and the third pipeline and is controlled by the seventh valve, the eighth valve and the ninth valve. When the tracers injected into the first module, the second module and the third module are of different types, the flowback fluid can be discharged together from the fourth drain port, and the concentrations of various tracers in the samples are detected respectively. By comparing the tracer flowback characteristic curves under the two sampling methods, the influence of the common flowback of multiple fracturing stages on the tracer flowback characteristics can be studied.

[0031] Furthermore, the types of fractures in the preset fracture module are different, and are provided with sandy membranes and filtration channels that can simulate the roughness of the fracture wall. The preset fracture module includes a transparent block with preset fractures of different types and filtration channels, which functions to simulate the migration channels of fluid and proppant in the reservoir, so as to facilitate the observation of the distribution of fluid and proppant in the fracture during fracturing and flowback. Therefore, in addition to studying the mechanism of tracer fracturing monitoring technology, the device can also conduct research on proppant laying and reflux rules under different fracture types and pumping parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of a visual experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers provided by the present invention;

[0033] Figure 2 for Figure 1 Schematic diagram of the third module;

[0034] Figure 3 is a cross-sectional view of the first module;

[0035] Figure 4 for Figure 3 A cross-sectional view from another perspective;

[0036] Figure 5It is a schematic diagram of a partial structure in the first pipeline, the second pipeline or the third pipeline.

[0037] 1-transparent block; 2-top cover plate; 3-temporary liquid storage pipeline; 4-sandy membrane; 5-first module; 6-second module; 7-third module; 8-liquid distribution tank; 9-delivery pump; 10-first pipeline; 11-second pipeline; 12-third pipeline; 13-first valve; 14-second valve; 15-third valve; 16-fourth valve; 17-fifth valve; 18-sixth valve; 19-return pump; 20-fourth pipeline; 21-first drainage port; 22-second drainage port; 23-third drainage port; 24-fourth drainage port; 25-seventh valve; 26-eighth valve; 27-ninth valve; 28-filtration channel; 29-hollow screw; 30-slit; 31-main seam structure; 32-first-level branch seam; 33-second-level branch seam.

[0038] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] In the embodiments of the present invention, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0041] In the embodiments of the present invention, the term "plurality" refers to two or more than two, and other quantifiers are similar.

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it can be understood by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present invention. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present invention can also be implemented. The division of the following embodiments is for the convenience of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other under the premise of no contradiction.

[0043] The present invention provides a visual experimental device based on tracer monitoring of the effect of horizontal well segmented multi-cluster fracturing. Figures 1 to 4The visualization experimental device for monitoring the effect of multi-cluster fracturing in horizontal wells based on tracers includes a pre-set fracture module, a pumping system, and a flowback system.

[0044] Among them, the function of the pre-set fracture module is to simulate the migration channel of fluid and proppant in the reservoir, so as to facilitate the observation of the migration status of fluid and proppant in the fracture during fracturing and backflow. The pre-set fracture module includes a first module 5, a second module 6 and a third module 7, wherein the first module 5, the second module 6 and the third module 7 all include a transparent block 1, a sandy film 4 and a top cover plate 2, wherein the transparent block 1 includes a first connecting block and a second connecting block spliced ​​together, wherein the first connecting block and the second connecting block respectively have a first splicing surface and a second splicing surface, wherein the top cover plate 2 is covered on the top of the first connecting block and the second connecting block and is sealed and fixed with the first connecting block and the second connecting block, wherein the top of the transparent block 1 of the first module 5, the second module 6 and the third module 7 is respectively provided with a main seam structure 31, wherein the transparent block 1 of the second module 6 and the third module 7 is respectively provided with a first-level branch seam 32 and is respectively connected to the main seam structure 31 corresponding to the first module 6, and the transparent block 1 of the third module 7 is provided with a second-level branch seam 33 and is connected to the first-level branch seam 32 corresponding to the first module 7. By attaching the sandy membrane 4 to the first joint surface and the second joint surface respectively, the proppant can be restricted from entering the filtration pore 28 .

[0045] The transparent block 1 may be made of, but is not limited to, phenolic resin.

[0046] It should be noted that the top cover plate 2 is arranged on the top of the crack structure of the first module 5, the second module 6 and the third module 7, so that on the one hand, the crack structure can be sealed to prevent the fracturing fluid from overflowing from the top of the first module 5, the second module 6 and the third module 7, and on the other hand, it can be used to fix the first connecting block and the second connecting block. The connection between the top cover plate 2 and the first connecting block and the second connecting block can be connected by bolts (such as hollow screws 29). The bottom of the main seam structure 31 also needs to be sealed to prevent the fracturing fluid from flowing out, and the specific sealing method can be a conventional sealing method.

[0047] The temporary liquid storage pipe 3 passes through the hollow screw 29 and communicates with the filtration channel 28. The bottom of the temporary liquid storage pipe 3 is designed with a thick pipe head to prevent the pipe from being squeezed out due to the pressure increase in the filtration channel 28 during pumping and backflow. The sandy membrane 4 simulates the rough wall of the crack and prevents the proppant from entering the filtration channel 28 and causing blockage. The function of the filtration channel 28 is to simulate the physical phenomenon of the fracturing fluid being lost into the matrix during the fracturing process and the physical phenomenon of the fluid seeping from the matrix into the crack under the action of the pressure difference during the backflow and production process.

[0048] Among them, the total volume of the crack structures on the first module 5, the second module 6 and the third module 7 are all the same, the first splicing surface and the second splicing surface of the first module 5, the second module 6 and the third module 7 respectively define their main seam structures 31, and the first splicing surface and the second splicing surface are respectively provided with sandy films 4.

[0049] Specifically, the fracture structure of the first module 5 includes a first main fracture, the fracture structure of the second module 6 includes a second main fracture and a first branch fracture connected to the second main fracture, and the fracture structure of the third module 7 includes a third main fracture, a second branch fracture connected to the third main fracture, and a third branch fracture connected to the second branch fracture. The total volume of the fracture structures on the first module 5, the second module 6, and the third module 7 are the same to compare the tracer flowback characteristics and proppant laying and reflux rules under different types of fracture conditions. It can be understood that the volume of the first main fracture is V1, the volume of the second main fracture is V2, the volume of the first branch fracture is V3, the volume of the third main fracture is V4, the volume of the second branch fracture is V5, and the volume of the third branch fracture is V6, V1=V2+V3=V4+V5+V6.

[0050] The pumping system is used to pump the configured fracturing fluid containing the tracer into the first module 5, the second module 6 and the third module 7. Specifically, the pumping system is connected to one side of the main seam structure 31 of the first module 5, the second module 6 and the third module 7, respectively, so as to facilitate pumping the fracturing fluid containing the tracer into the cracks of the first module 5, the second module 6 and the third module 7, respectively.

[0051] The pumping system includes a liquid preparation tank 8, a delivery pump 9, a first pipeline 10, a second pipeline 11, and a third pipeline 12. The delivery pump 9 includes an inlet, a first outlet, a second outlet, and a third outlet. The liquid preparation tank 8 is connected to the inlet. The first outlet, the second outlet, and the third outlet are connected to the main seam structure 31 of the first module 5, the second module 6, and the third module 7 through the first pipeline 10, the second pipeline 11, and the third pipeline 12, respectively. A stirrer is provided in the liquid preparation tank 8 to evenly mix the tracer into the fracturing fluid. The first pipeline 10, the second pipeline 11, and the third pipeline 12

[0052] The first outlet, the second outlet, and the third outlet are respectively connected to a first valve 13, a second valve 14, and a third valve 15, which are used to control the opening or closing of the first outlet, the second outlet, and the third outlet, respectively.

[0053] The first pipeline 10, the second pipeline 11, and the third pipeline 12 are respectively provided with a first drain port 21, a second drain port 22, and a third drain port 23; the first drain port 21, the second drain port 22, and the third drain port 23 are respectively connected to a fourth valve 16, a fifth valve 17, and a sixth valve 18, and the fourth valve 16, the fifth valve 17, and the sixth valve 18 are respectively used to control the opening or closing of the first drain port 21, the second drain port 22, and the third drain port 23.

[0054] The pumping system also includes a fourth pipeline 20, which is connected to the first pipeline 10, the second pipeline 11, and the third pipeline 12 respectively, and the fourth pipeline 20 is provided with a fourth drain port 24; a seventh valve 25 for controlling whether the fourth pipeline 20 is connected to the first pipeline 10 at the connection, an eighth valve 26 for controlling whether the fourth pipeline 20 is connected to the second pipeline 11 at the connection, and a ninth valve 27 for controlling whether the fourth pipeline 20 is connected to the third pipeline 12 at the connection.

[0055] See also Figure 5 The first pipeline 10, the second pipeline 11, and the third pipeline 12 are respectively provided with slits 30, and the first pipeline 10, the second pipeline 11, and the third pipeline 12 are respectively connected with the main seam structures 31 of the first module 5, the second module 6, and the third module 7 through the slits 30. The fracturing fluid and the proppant are pumped into or discharged from the fracture structure through the slits 30.

[0056] The backflow system includes a backflow pump 19, a temporary liquid storage pipe 3 arranged above the top cover plate 2, and a filtration channel 28. The first module 5, the second module 6, and the third module 7 are all connected to the temporary liquid storage pipe 3. The temporary liquid storage pipes 3 on the first module 5, the second module 6, and the third module 7 are respectively connected to the cracks thereon. The filtration channels 28 on the first module 5, the second module 6, and the third module 7 are respectively arranged in the first module 5, the second module 6, and the third module 7 and extend to the splicing surface. The filtration channels 28 on the first module 5, the second module 6, and the third module 7 are respectively connected to the temporary liquid storage pipe 3 on the first module 5, the second module 6, and the third module 7. The backflow pump 19 is respectively connected to the temporary liquid storage pipe 3 on the first module 5, the second module 6, and the third module 7. By setting up the flowback system, after the pumping stage is over, the flowback pump 19 can be turned on to pump the fracturing fluid in the temporary liquid storage pipeline 3 out through the filter loss channel 28, and the fracturing fluid passes through the fracture structure and pipelines (first pipeline 10 / second pipeline 11 / third pipeline 12) in turn and is discharged from the corresponding drainage ports (first drainage port 21 / second drainage port 22 / third drainage port 23 / fourth drainage port 24).

[0057] The temporary liquid storage pipe 3 has a first end connected to the filtration channel 28 and a second end opposite to the first end, and the inner diameter of the first end is greater than the inner diameter of the second end.

[0058] The backflow pump 19 is in a closed state during the pumping stage (when the delivery pump 9 is working). When pumping into the first module 5, the first valve 13 is opened, the second valve 14 and the third valve 15 are closed, and the fourth valve 16 is in a closed state. At this time, the fracturing fluid is pumped into the first module 5 through the first pipeline 10. When pumping into the second module 6, the second valve 14 is opened, the first valve 13 and the third valve 15 are closed, and the fifth valve 17 is in a closed state. At this time, the fracturing fluid is pumped into the second module 6 through the second pipeline 11. When pumping into the third module 7, the third valve 15 is opened, the first valve 13 and the second valve 14 are closed, and the sixth valve 18 is in a closed state. At this time, the fracturing fluid is pumped into the third module 7 through the third pipeline 12.

[0059] When the tracers in the fracturing fluid injected into the first module 5, the second module 6, and the third module 7 are of the same type, in order to avoid confusion, the fourth valve 16, the fifth valve 17, and the sixth valve 18 are opened, and the flowback fluid is discharged from the first drain port 21, the second drain port 22, and the third drain port 23 respectively. The fourth drain port 24 on the fourth pipeline 20 is controlled by the seventh valve 25, the eighth valve 26, and the ninth valve 27. When the tracers in the fracturing fluid injected into the first module 5, the second module 6, and the third module 7 are of different types, the flowback fluid is discharged together from the fourth drain port 24, and the concentration of each type of tracer in the sample is detected respectively; in other methods, the fourth valve 16, the fifth valve 17, and the sixth valve 18 can also be opened, and samples are taken and tested at the first drain port 21, the second drain port 22, and the third drain port 23 at the same time, and the tracer flowback characteristic curves under the two sampling methods are compared to study the influence of the common flowback of multiple fracturing stages on the tracer flowback characteristics.

[0060] Furthermore, in order to better compare the tracer flowback characteristic curves under different types of fractures, the pumping system should keep the same pumping parameters such as liquid volume, displacement, sand adding method, sand volume, sand ratio, etc. when pumping to the first module 5, the second module 6, and the third module 7. In order to visualize the migration and diffusion behavior of the tracer in the transparent module, the tracer is dyed with a specific dye.

[0061] In addition, the pumping system can be set with different pumping parameters, including sand ratio, particle size combination, displacement, and sand adding method.

[0062] The present invention provides a visualization experimental method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers. The experimental method includes an embodiment of the above-mentioned experimental device, and the beneficial effects of the above-mentioned experimental device can be applied to the experimental method.

[0063] The experimental method includes:

[0064] Step S100, pumping the fracturing fluid mixed with the tracer and the proppant into the first module 5, the second module 6, and the third module 7 through the pumping system, so that part of the fracturing fluid passes through the sandy membrane 4 and enters the filtration channel 28 respectively, and enters the corresponding temporary liquid storage pipeline 3 through the filtration channel 28, and the sandy membrane 4 on the first splicing surface and the second splicing surface restricts the proppant from entering the filtration channel 28;

[0065] Step S200, start the flowback pump 19 to pump out the fracturing fluid in the temporary liquid storage pipeline 3;

[0066] Step S300, based on whether the types of tracers injected into the first module 5, the second module 6, and the third module 7 are the same, samples are taken at the corresponding drainage ports to detect the tracer concentration, and tracer flowback characteristic curves under different fracture type conditions are drawn.

[0067] Specifically, when the tracer types injected into the first module 5, the second module 6, and the third module 7 are of the same type, the fourth valve 16, the fifth valve 17, and the sixth valve 18 are opened to discharge the return fluid from the first drain port 21, the second drain port 22, and the third drain port 23. Samples are taken from the first drain port 21, the second drain port 22, and the third drain port 23 to detect the concentration of the tracer, and tracer return characteristic curves under different fracture type conditions are drawn.

[0068] When the types of tracers injected into the first module 5, the second module 6, and the third module 7 are different, the seventh valve 25, the eighth valve 26, and the ninth valve 27 are opened to discharge the return fluid from the fourth drain port 24, and samples are taken at the fourth drain port 24 to detect the concentration of various tracers, and tracer return characteristic curves under different fracture type conditions are drawn.

[0069] Obviously, the embodiments described above are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, ordinary technicians in this field can make other different forms of changes or modifications without creative work, which should fall within the scope of protection of the present invention.

Claims

1. A visual experimental device for monitoring the effect of multi-cluster fracturing in horizontal wells based on tracers, characterized in that: include: A pre-set crack module, comprising a first module, a second module and a third module, wherein the first module, the second module and the third module all comprise a transparent block, a sandy film and a top cover plate, wherein the transparent block comprises a first connecting block and a second connecting block spliced ​​together, wherein the first connecting block and the second connecting block respectively have a first splicing surface and a second splicing surface, wherein the top cover plate is covered on the top of the first connecting block and the second connecting block and is sealed and fixed with the first connecting block and the second connecting block, wherein the tops of the transparent blocks of the first module, the second module and the third module are respectively provided with a main seam structure, wherein the transparent blocks of the second module and the third module are respectively provided with a first-level branch seam and are respectively connected to the main seam structure corresponding thereto, wherein the transparent block of the third module is provided with a second-level branch seam and is connected to the first-level branch seam corresponding thereto, wherein the total volume of the crack structures on the first module, the second module and the third module are the same, wherein the first splicing surface and the second splicing surface of the first module, the second module and the third module respectively define their main seam structures, and the first splicing surface and the second splicing surface are respectively provided with a sandy film; A pumping system, connected to one side of the main fracture structure of the first module, the second module and the third module respectively, for pumping a fracturing fluid containing a tracer into the fractures of the first module, the second module and the third module respectively; A flowback system, comprising a flowback pump, a temporary liquid storage pipe and a filtration channel arranged above the top cover plate, wherein the first module, the second module and the third module are all connected with the temporary liquid storage pipe, the temporary liquid storage pipes on the first module, the second module and the third module are respectively communicated with the cracks thereon, the filtration channels on the first module, the second module and the third module are respectively arranged in the first module, the second module and the third module and extend to the splicing surface, the filtration channels on the first module, the second module and the third module are respectively communicated with the temporary liquid storage pipes on the first module, the second module and the third module, and the flowback pump is respectively connected with the temporary liquid storage pipes on the first module, the second module and the third module; The pump injection system includes a liquid preparation tank, a delivery pump, a first pipeline, a second pipeline, and a third pipeline. The delivery pump includes an inlet, a first outlet, a second outlet, and a third outlet. The liquid preparation tank is connected to the inlet. The first outlet, the second outlet, and the third outlet are connected to the main seam structures of the first module, the second module, and the third module through the first pipeline, the second pipeline, and the third pipeline, respectively. The first outlet, the second outlet, and the third outlet are respectively connected to a first valve, a second valve, and a third valve, and the first valve, the second valve, and the third valve are respectively used to control the opening or closing of the first outlet, the second outlet, and the third outlet.

2. The visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers according to claim 1, characterized in that: The first pipe, the second pipe, and the third pipe are respectively provided with a first liquid discharge port, a second liquid discharge port, and a third liquid discharge port; The first liquid discharge port, the second liquid discharge port, and the third liquid discharge port are respectively connected to a fourth valve, a fifth valve, and a sixth valve, and the fourth valve, the fifth valve, and the sixth valve are respectively used to control the opening or closing of the first liquid discharge port, the second liquid discharge port, and the third liquid discharge port.

3. The visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers according to claim 1, characterized in that: The pump injection system further comprises a fourth pipeline, the fourth pipeline is respectively connected with the first pipeline, the second pipeline, and the third pipeline, and the fourth pipeline is provided with a fourth liquid discharge port; The connection between the fourth pipeline and the first pipeline is connected to a seventh valve for controlling whether they are connected, the connection between the fourth pipeline and the second pipeline is connected to an eighth valve for controlling whether they are connected, and the connection between the fourth pipeline and the third pipeline is connected to a ninth valve for controlling whether they are connected.

4. The visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers according to claim 1, characterized in that: The first pipeline, the second pipeline, and the third pipeline are respectively provided with slits, and the first pipeline, the second pipeline, and the third pipeline are respectively connected with the main seam structures of the first module, the second module, and the third module through the slits.

5. The visualization experimental device for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers according to claim 1, characterized in that: The temporary liquid storage pipe has a first end connected to the filtration channel and a second end opposite to the first end, and the inner diameter of the first end is greater than the inner diameter of the second end.

6. A visual experimental method for monitoring the effect of multi-cluster fracturing in horizontal wells based on tracers, characterized in that: The experimental method uses the experimental device according to any one of claims 1 to 5 to conduct the experiment, and the experimental method includes: Pumping the fracturing fluid mixed with the tracer and the proppant into the first module, the second module, and the third module respectively through the pumping system, so that part of the fracturing fluid enters the filtration pores through the sandy membranes, and enters the corresponding temporary liquid storage pipeline through the filtration pores, and the sandy membranes on the first splicing surface and the second splicing surface restrict the proppant from entering the filtration pores; Start the flowback pump to pump out the fracturing fluid in the temporary storage pipeline; According to whether the types of tracers injected into the first module, the second module, and the third module are the same, samples are taken at the corresponding drainage ports to detect the tracer concentration, and tracer flowback characteristic curves under different fracture type conditions are drawn.

7. The visualization experimental method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers according to claim 6, characterized in that: According to whether the types of tracers injected into the first module, the second module, and the third module are the same, sampling is performed at the corresponding drainage ports to detect the concentration of the tracers, and tracer flowback characteristic curves under different fracture type conditions are drawn, including: When the tracer types injected into the first module, the second module, and the third module are of the same type, the fourth valve, the fifth valve, and the sixth valve are opened to discharge the return fluid from the first drain port, the second drain port, and the third drain port. Samples are taken from the first drain port, the second drain port, and the third drain port to detect the tracer concentration, and tracer return characteristic curves under different fracture type conditions are drawn.

8. The visualization experimental method for monitoring the effect of staged multi-cluster fracturing of horizontal wells based on tracers according to claim 6, characterized in that: According to whether the types of tracers injected into the first module, the second module, and the third module are the same, sampling is performed at the corresponding drainage ports to detect the concentration of the tracers, and tracer flowback characteristic curves under different fracture type conditions are drawn, including: When the types of tracers injected into the first module, the second module, and the third module are different, the seventh valve, the eighth valve, and the ninth valve are opened to discharge the return fluid from the fourth drainage port. Samples are taken at the fourth drainage port to detect the concentrations of various tracers, and tracer return characteristic curves under different fracture type conditions are drawn.

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