Visual experiment device and method for simulating migration process of plugging agent particles in rock crack

Abstract

The invention discloses a visual experimental device for simulating the migration process of plugging agent particles in rock fracture.The visual experimental device comprises a fluid injection system, a fracture fluid simulation system and a data collection system, the fluid injection system is connected with the fracture fluid simulation system, and the fluid injection system injects experimental base fluid into the fracture fluid simulation system; the crack fluid simulation system is used for placing a rock sample with cracks and through holes and enabling the rock sample to be soaked in the experimental base fluid, and the data collection system is used for recording the migration, accumulation and bridging process of particles of the experimental base fluid in the cracks of the rock sample. The migration, accumulation and bridging mechanism of the plugging agent particles in the crack under the real rock crack condition is explored, the understanding of the mechanical behavior of the plugging agent particles in the natural crack is improved, and an important theoretical basis is provided for drilling plugging site construction operation.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum engineering crack plugging, and in particular to a visualization experimental device and method for simulating the migration process of plugging agent particles inside rock cracks. Background Art

[0002] Oil and natural gas resources occupy an important position in the world's energy consumption structure. With the continuous increase in global energy consumption and the gradual decrease in the production of conventional and easily exploitable oil and gas, oil and gas exploration and development have gradually focused on deeper and more complex reservoirs. These reservoirs often have developed cracks, which can easily cause drilling fluid loss. In severe cases, they may also induce a series of complex underground accidents such as well collapse, stuck drill, and blowout. Adding plugging agents to the drilling fluid to plug the cracks is the most common solution to overcome such problems.

[0003] Since the distribution of underground cracks is difficult to predict and the spatial distribution of cracks is complex, in actual production activities, underground accidents such as difficulty in one-time plugging and repeated leakage are often encountered. The main reason for these accidents is the insufficient understanding of the migration and bridging mechanism of plugging agent particles in natural fractures.

[0004] The existing patent with publication number CN110295887A discloses an experimental device and working method for visualizing the law of particle migration. The transparent resin is 3D printed in combination with the results of 3D scanning of real rock cores to obtain a transparent rough fracture surface, and finally a set of experimental device and method for visualizing particle migration is constructed. However, the device lacks consideration of formation conditions, does not consider the seepage properties and capacity of rocks in actual formations, and does not consider the impact of particles on real formation rocks and fractures.

[0005] Therefore, there is an urgent need for a visual experimental device that simulates the migration process of plugging agent particles inside rock fractures. Summary of the invention

[0006] On one hand, the present invention provides a visualization experimental device for simulating the migration process of plugging agent particles in rock fractures, so as to solve the technical problems that the prior art cannot directly observe the migration and bridging behavior of plugging agent particles in rock fractures, and it is difficult to conduct in-depth exploration of the particle migration and bridging mechanism. On the other hand, the present invention provides an experimental method for simulating the visualization experimental device for the migration process of plugging agent particles in rock fractures.

[0007] The first aspect of the present invention provides a visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, comprising a fluid injection system, a fracture fluid simulation system and a data collection system, wherein the fluid injection system is connected to the fracture fluid simulation system, the fluid injection system injects experimental base fluid into the fracture fluid simulation system, the fracture fluid simulation system is used to place rock samples with fractures and through holes and immerse the rock samples in the experimental base fluid, and the data collection system is used to record the migration, accumulation and bridging process of the particles of the experimental base fluid in the fractures of the rock samples.

[0008] The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the fluid injection system includes a liquid reservoir, a water pump, an injection pipeline, a flow pressure regulating device and an outflow pipeline, the liquid reservoir is connected through the water pump through the injection pipeline, the injection pipeline extends into the rock sample, the injection pipeline is provided with the flow regulating device, and the outflow pipeline is arranged at the bottom of the fracture fluid simulation system to discharge waste liquid.

[0009] The visualized experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the flow pressure regulating device includes a pressure regulating valve and a flow meter, and the injection pipeline is sequentially provided with the pressure regulating valve and the flow meter along the flow direction of the base liquid to which the plugging agent is added.

[0010] The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the fracture fluid simulation system includes a rock sample holding device and a clamp, the rock sample is placed in the rock sample holding device, the injection pipeline extends into the rock sample holding device and into the rock sample, the outflow pipeline is arranged at the bottom of the rock sample holding device, and the clamp clamps and fixes the rock sample holding device.

[0011] The visualized experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the rock sample holding device comprises a top cover, bolts and a rock sample container, the top cover is arranged on the top of the rock sample container by the bolts, the clamp clamps and fixes the rock sample container, the rock sample container is used to place the rock sample, a waste liquid diversion channel is provided on the inner wall of the rock sample container, and the outflow pipeline is connected to the waste liquid diversion channel.

[0012] The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the waste liquid diversion channel includes a diversion pipe and a liquid storage chamber, the diversion pipe is provided on the inner wall of the rock sample container, the upper part of the liquid storage chamber is connected to the diversion pipe, and the liquid storage chamber is connected to the outflow pipeline.

[0013] The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the data collection system includes a high-definition camera and a waste liquid barrel, the high-definition camera is used to record the migration, accumulation and bridging process of the particles of the experimental base fluid in the rock sample fractures, and the waste liquid barrel is connected to the outflow pipeline.

[0014] In the visualized experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the experimental base fluid comprises base fluid and base fluid with plugging agent added thereto.

[0015] In the visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, preferably, the material of the rock sample containing device is a transparent material.

[0016] The second aspect of the present invention provides an experimental method based on the visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, comprising the following steps: Place the rock sample into the fracture fluid simulation system and the base fluid into the fluid injection system to complete the preparation work; Injecting the base fluid into the fracture fluid simulation system to ensure that the entire rock sample is immersed in the base fluid; Adding a base fluid of a plugging agent through the fluid injection system, injecting the base fluid with the plugging agent into the fracture fluid simulation system, and using a data collection system to perform experimental records on the rock sample; When the base liquid added with the plugging agent is exhausted, the fluid supply of the fluid injection system is stopped and the experiment ends.

[0017] The beneficial effects are: The fracture fluid simulation system of the present invention is made of colorless and transparent materials, which can ensure the feasibility of observation during the experiment; at the same time, real rock samples are selected for experiments to restore the actual situation of drilling production operations to the greatest extent, ensuring its authenticity and fit.

[0018] The present invention conducts experiments by using a visualization experimental device to simulate the migration process of plugging agent particles inside rock fractures, and uses a high-definition camera to record and analyze the entire process of particle migration and bridging behavior in the fracture space. The process of particle migration, accumulation and bridging in rock fractures can be observed, providing a technical means for revealing the migration and bridging behavior of particles in real rock fractures from a microscopic level and conducting in-depth research on its mechanism.

[0019] The present invention explores the migration, accumulation and bridging mechanism of plugging agent particles in cracks under real rock fracture conditions, improves the understanding of the mechanical behavior of plugging agent particles in natural cracks, and provides an important theoretical basis for on-site construction of drilling plugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of an embodiment of the present invention; Figure 2 is a schematic diagram of the structure of a fracture fluid simulation system according to an embodiment of the present invention; In the figure: 101. Liquid reservoir; 102. Water pump; 103. Pressure control valve; 104. Flow meter; 105. Clamp; 201, injection pipeline; 202, top cover; 203, bolts; 204, rock sample container; 205, rock sample; 206, outflow pipeline; 207, diversion pipeline; 208, liquid storage chamber; 301. High-definition camera; 302. Waste liquid barrel. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The present invention provides a visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, including a fluid injection system, a fracture fluid simulation system and a data collection system, wherein the fluid injection system is connected to the fracture fluid simulation system, the fluid injection system injects experimental base fluid into the fracture fluid simulation system, the fracture fluid simulation system is used to place rock samples with fractures and immerse the rock samples in the experimental base fluid, and the data collection system is used to record the migration, accumulation and bridging process of the particles of the experimental base fluid in the fractures of the rock samples. The present invention explores the migration, accumulation and bridging mechanism of plugging agent particles in fractures under real rock fracture conditions, improves the understanding of the mechanical behavior of plugging agent particles in natural fractures, and provides an important theoretical basis for on-site construction of drilling plugging.

[0024] The entire technical process is described in detail below using a visualization experimental device that simulates the migration process of plugging agent particles inside rock fractures as an example.

[0025] Example 1 like Figure 1 and Figure 2 As shown, a visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures includes a fluid injection system, a fracture fluid simulation system and a data collection system. The fluid injection system is connected to the fracture fluid simulation system. The fluid injection system injects experimental base fluid into the fracture fluid simulation system. The fracture fluid simulation system is used to place a rock sample 205 with fractures and through holes and immerse the rock sample 205 in the experimental base fluid. The data collection system is used to record the migration, accumulation and bridging process of the particles of the experimental base fluid in the fractures of the rock sample 205.

[0026] The experimental base fluid includes base fluid and base fluid with plugging agent added, and the base fluid refers to drilling fluid without plugging agent added, which is the prior art.

[0027] The rock sample 205 has cracks, and there is a through hole in the middle of the rock sample 205, so as to simulate the situation that a wellbore exists in the formation in actual production.

[0028] Continue to refer to Figure 1 As shown, the fluid injection system includes a liquid reservoir 101, a water pump 102, an injection pipeline 201, a flow pressure regulating device and an outflow pipeline 206. The liquid reservoir 101 is connected to the injection pipeline 201 through the water pump 102. The injection pipeline 201 extends into the through hole of the rock sample 205. The injection pipeline 201 is provided with the flow regulating device. The outflow pipeline 206 is arranged at the bottom of the fracture fluid simulation system to discharge the waste liquid.

[0029] The liquid reservoir 101 is used to store base liquid or base liquid for adding plugging agent.

[0030] The water pump 102 is a driving element that provides pressure drive; The pressure regulating valve 103 is a regulating element for applying a constant pressure; The flow meter 104 is a device for measuring the flow rate of the liquid in the injection pipeline 201 .

[0031] The flow pressure regulating device comprises a pressure regulating valve and a flow meter 104 , and the injection pipeline 201 is provided with the pressure regulating valve and the flow meter 104 in sequence along the flow direction of the base liquid into which the plugging agent is added.

[0032] Continue as Figure 2As shown, the fracture fluid simulation system includes a rock sample holding device and a clamp 105, a rock sample 205 is placed in the rock sample holding device, an injection pipeline 201 extends into the rock sample holding device and extends into the through hole of the rock sample 205, an outflow pipeline 206 is arranged at the bottom of the rock sample holding device, and the clamp 105 clamps and fixes the rock sample holding device.

[0033] The rock sample receiving device includes a top cover 202, a bolt 203 and a rock sample receiving container 204. The top cover 202 is arranged on the top of the rock sample receiving container 204 by means of the bolt 203, and the bolt 203 penetrates the top cover 202. A rubber insulating layer is arranged between the top cover 202 and the rock sample receiving container 204 to ensure the sealing of the experiment. The top cover 202 is provided with a water injection hole, and the water injection hole is connected to the injection pipeline 201. The clamp 105 clamps and fixes the rock sample receiving container 204. A groove is arranged in the rock sample receiving container 204, and the groove is used to place the rock sample 205. A waste liquid diversion channel is arranged on the inner wall of the rock sample receiving container 204. A drainage hole is arranged at the bottom of the rock sample receiving container 204. One end of the outflow pipeline 206 is connected to the waste liquid diversion channel through the drainage hole, and the other end of the outflow pipeline 206 is connected to the waste liquid bucket 302.

[0034] The rock sample container 204 and the top cover 202 are both made of transparent materials, that is, the rock sample container 204 and the top cover 202 are made of transparent polymethyl methacrylate material.

[0035] The waste liquid diversion channel includes a diversion pipe 207 and a liquid storage chamber 208 . The inner wall of the rock sample container 204 is provided with a diversion pipe 207 . The upper part of the liquid storage chamber 208 is connected to the diversion pipe 207 , and the liquid storage chamber 208 is connected to the outflow pipeline 206 .

[0036] The data collection system includes a high-definition camera 301 and a waste liquid barrel 302 . The high-definition camera 301 is used to record the process of the migration, accumulation and bridging of particles of the experimental base liquid in the cracks of the rock sample 205 . The waste liquid barrel 302 is connected to the outflow pipeline 206 .

[0037] Example 2 The second aspect of the present invention provides an experimental method based on the visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, comprising the following steps: S1: Place the rock sample 205 into the fracture fluid simulation system, place the base fluid into the fluid injection system, and complete the preparation work.

[0038] Step S1 specifically includes step S11, step S12 and step S13: S11: Select the required rock sample 205 with cracks and place it in the rock sample container 204.

[0039] S12: Use bolts 203 to connect the top cover 202 and the rock sample container 204 together, and place the base liquid in the liquid reservoir 101.

[0040] S13: Turn off the water pump 102 and the pressure control valve 103, assemble the device in sequence, and complete the preparation work.

[0041] S2: Inject the base fluid into the fracture fluid simulation system to ensure that the entire rock sample 205 is immersed in the base fluid.

[0042] Step S2 specifically includes step S21 and step S22: S21: Turn on the water pump 102 and the pressure control valve 103, inject the experimental base without plugging agent particles into the rock sample container 204, remove the air in the experimental device, and ensure that the entire rock sample 205 is immersed in the experimental base without plugging agent particles.

[0043] S22: Turn off the water pump 102 and the pressure control valve 103.

[0044] S3: adding a base fluid of a plugging agent through the fluid injection system, injecting the base fluid with the plugging agent into the fracture fluid simulation system, and using a data collection system to perform experimental records on the rock sample 205 .

[0045] Step S3 specifically includes step S31 and step S32: S31: Replace the liquid in the liquid reservoir 101 with a base liquid to which a plugging agent is added.

[0046] S32: Reopen the water pump 102 and the pressure control valve 103, inject the base liquid with plugging agent into the rock sample container 204, and adjust the high-definition camera 301 so that the high-definition camera 301 faces the cracks of the cracked rock sample 205 to record the experiment.

[0047] S4: When the base liquid added with the plugging agent is exhausted, the fluid supply of the fluid injection system is stopped and the experiment ends.

[0048] Step S4 specifically includes step S41 and step S42: S41: When the base liquid added with the plugging agent in the liquid reservoir 101 is about to be exhausted, the water pump 102 is turned off, and the pressure regulating valve 103 is used to relieve the pressure of the injection pipeline 201; S42: dismantle and clean the injection pipeline 201, the outflow pipeline 206 and the rock sample container 204, and the experiment ends.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures, characterized in that: The invention comprises a fluid injection system, a fracture fluid simulation system and a data collection system. The fluid injection system is connected to the fracture fluid simulation system. The fluid injection system injects experimental base fluid into the fracture fluid simulation system. The fracture fluid simulation system is used to place rock samples with fractures and through holes and immerse the rock samples in the experimental base fluid. The data collection system is used to record the process of migration, accumulation and bridging of particles of the experimental base fluid in the fractures of the rock samples.

2. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to claim 1 is characterized in that: The fluid injection system includes a liquid reservoir, a water pump, an injection pipeline, a flow pressure regulating device and an outflow pipeline. The liquid reservoir is connected to the injection pipeline through the water pump. The injection pipeline extends into the rock sample. The flow regulating device is arranged on the injection pipeline. The outflow pipeline is arranged at the bottom of the fracture fluid simulation system to discharge waste liquid.

3. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to claim 2 is characterized in that: The flow pressure regulating device comprises a pressure regulating valve and a flow meter, and the injection pipeline is provided with the pressure regulating valve and the flow meter in sequence along the flow direction of the base liquid to which the plugging agent is added.

4. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to claim 3 is characterized in that: The fracture fluid simulation system includes a rock sample holding device and a clamp, the rock sample is placed in the rock sample holding device, the injection pipeline extends into the rock sample holding device and into the rock sample, the outflow pipeline is arranged at the bottom of the rock sample holding device, and the clamp clamps and fixes the rock sample holding device.

5. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to claim 4 is characterized in that: The rock sample holding device comprises a top cover, bolts and a rock sample container, wherein the top cover is arranged on the top of the rock sample container by the bolts, the clamp clamps and fixes the rock sample container, the rock sample container is used to place the rock sample, a waste liquid diversion channel is arranged on the inner wall of the rock sample container, and the outflow pipeline is connected with the waste liquid diversion channel.

6. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to claim 5 is characterized in that: The waste liquid diversion channel includes a diversion pipe and a liquid storage chamber. The diversion pipe is arranged on the inner wall of the rock sample container. The upper part of the liquid storage chamber is connected to the diversion pipe, and the liquid storage chamber is connected to the outflow pipeline.

7. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to claim 6 is characterized in that: The data collection system includes a high-definition camera and a waste liquid barrel. The high-definition camera is used to record the process of migration, accumulation and bridging of particles of the experimental base liquid in the rock sample fractures. The waste liquid barrel is connected to the outflow pipeline.

8. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to any one of claims 1 to 7, characterized in that: The experimental base fluid includes a base fluid and a base fluid with a plugging agent added thereto.

9. The visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to claim 8 is characterized in that: The material of the rock sample containing device is transparent material.

10. An experimental method based on the visualization experimental device for simulating the migration process of plugging agent particles inside rock fractures according to any one of claims 1 to 9, comprising the following steps: Place the rock sample into the fracture fluid simulation system and the base fluid into the fluid injection system to complete the preparation work; Injecting the base fluid into the fracture fluid simulation system to ensure that the entire rock sample is immersed in the base fluid; Adding a base fluid of a plugging agent through the fluid injection system, injecting the base fluid with the plugging agent into the fracture fluid simulation system, and using a data collection system to perform experimental records on the rock sample; When the base liquid added with the plugging agent is exhausted, the fluid supply of the fluid injection system is stopped and the experiment ends.

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