Drilling fluid invasion test system and drilling fluid invasion test method

Abstract

This invention belongs to the field of oil and gas field drilling technology and discloses a drilling fluid invasion test system and a drilling fluid invasion test method. The drilling fluid invasion test system includes an injection pipeline and seepage modules, with the seepage modules sequentially arranged along the length of the injection pipeline. Each seepage module has a circulation chamber and a rock mass chamber. The rock mass chamber is used to contain the rock mass to be tested, and the circulation chamber has an inlet and an outlet. In two adjacent seepage modules, along the flow direction of the liquid in the injection pipeline, the outlet of the upstream seepage module is connected to the inlet of the downstream seepage module. A first pressure gauge is installed on the injection pipeline at each inlet, and a first pressure regulating valve is installed on the injection pipeline at each outlet. This drilling fluid invasion test method can simultaneously perform invasion tests on multiple rock masses to be tested, thereby simulating the filtration process of drilling fluid into the reservoir matrix at different sections of a horizontal well under real-world conditions.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field drilling technology, and in particular to a drilling fluid invasion test system and a drilling fluid invasion test method. Background Technology

[0002] During oil and gas field drilling, drilling fluid can invade the surrounding reservoir matrix under the influence of pressure differential. After invasion, it may cause physical and chemical changes in the oil and gas reservoir rocks and the fluids within the pores, leading to changes in pore space, reduced permeability, and increased seepage resistance. These changes in the reservoir matrix can ultimately lead to reduced oil and gas well production, and in severe cases, even cause the well to lose its economic value. Therefore, it is necessary to conduct experimental tests on the invasion of drilling fluid into the reservoir matrix during drilling to clarify the impact of drilling fluid invasion on the reservoir.

[0003] Most existing drilling fluid invasion testing devices can only meet the needs of fixed-point experimental testing and cannot accurately reproduce and characterize the dynamic invasion process of drilling fluid in the reservoir. In particular, for heterogeneous horizontal wells, they cannot accurately simulate the differentiated invasion between different well sections, which restricts researchers' understanding of the drilling fluid invasion process during horizontal well drilling. Summary of the Invention

[0004] The purpose of this invention is to provide a drilling fluid invasion test system and a drilling fluid invasion test method, which can simulate the invasion process of drilling fluid into the reservoir matrix in different sections of a horizontal well in groups, so as to improve people's understanding of the drilling fluid invasion process in the reservoir matrix during horizontal well drilling.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] The drilling fluid intrusion test system includes:

[0007] An injection pipeline, wherein a pressure pump is installed on the injection pipeline;

[0008] At least two seepage modules are arranged sequentially along the length of the injection pipeline;

[0009] The seepage module has an interconnected circulation chamber and a rock mass chamber. The rock mass chamber is used to contain the rock mass to be tested. The circulation chamber has an inlet and an outlet. A seepage hole is opened at the end of the rock mass chamber away from the circulation chamber. In two adjacent seepage modules, along the flow direction of the liquid in the injection pipeline, the outlet of the upstream seepage module is connected to the inlet of the downstream seepage module. A first pressure gauge is installed on the injection pipeline at each inlet, and a first pressure regulating valve is installed on the injection pipeline at each outlet.

[0010] Preferably, the seepage module further includes a seepage cavity, which is connected to the rock mass cavity through the seepage hole, and the seepage cavity is used to contain formation fluids;

[0011] The outlet of the seepage cavity is equipped with a second pressure regulating valve and a second pressure gauge.

[0012] Preferably, the drilling fluid intrusion test system further includes a second recovery container, and the outlet of the seepage cavity is connected to a filtrate pipeline, and the outlet of the seepage cavity is connected to the interior of the second recovery container through the filtrate pipeline.

[0013] Preferably, the drilling fluid invasion test system further includes a return pipeline and a first recovery container, wherein the return pipeline is connected to the end of the injection pipeline, and the injection pipeline is connected to the interior of the first recovery container through the return pipeline.

[0014] Preferably, the space of the rock cavity matches the shape of the rock mass to be tested.

[0015] Preferably, a viewing window is provided on the outer wall of the rock mass cavity.

[0016] The drilling fluid invasion test method, using the aforementioned drilling fluid invasion test system, includes the following steps:

[0017] S1. Load each of the rock masses to be tested into the rock mass cavity;

[0018] S2. The circulation chamber of each of the seepage modules is filled with formation fluid;

[0019] S3. Start the pressurization pump and inject drilling fluid into the injection pipeline;

[0020] S4. Adjust the opening of each of the first pressure regulating valves so that the pressure difference between the circulation chamber and the outlet of the rock mass chamber reaches the preset pressure difference P.

[0021] S5. Observe the penetration depth of the drilling fluid.

[0022] Preferably, step S1 specifically includes:

[0023] According to the contact sequence of the drilling fluid during the actual drilling process, each of the rock masses to be tested is sequentially installed in the rock cavity of each of the seepage modules along the flow direction of the drilling fluid in the injection pipeline.

[0024] Preferably, step S3 includes the following step before starting the pressurization pump:

[0025] A dyeing material is added to the drilling fluid.

[0026] Preferably, the process includes the following steps before step S1:

[0027] A transparent coating with the opposite polarity to the drilling fluid is applied to the surface of the rock mass to be tested.

[0028] The beneficial effects of this invention are as follows:

[0029] The drilling fluid invasion testing system provided by this invention includes an injection pipeline and at least two seepage modules. Since each seepage module has an interconnected circulation chamber and a rock mass chamber (the rock mass chamber is used to contain the rock mass to be tested), and the seepage module is located on the injection pipeline with an inlet for fluid input, the seepage module can test the invasion of drilling fluid into the rock mass. Because a pressure pump is installed on the injection pipeline, and each circulation chamber is equipped with a first pressure gauge and a first pressure regulating valve, the drilling fluid pressure in each circulation chamber can be adjusted according to actual conditions to meet diverse experimental testing needs under different geological conditions. Since this drilling fluid invasion testing system has at least two seepage modules, and these at least two seepage modules are connected along the injection pipeline... The pipelines are sequentially arranged along their length in the injection pipeline, with the outlet of the upstream seepage module connected to the inlet of the downstream seepage module. Thus, multiple seepage modules are connected in series through the injection pipeline to form a series system. The liquid in the injection pipeline can sequentially enter the circulation chamber and flow through the test rock masses in multiple rock mass cavities under different pressure conditions. Therefore, this drilling fluid invasion test system can simultaneously conduct invasion tests on multiple test rock masses, thereby simulating the filtration process of drilling fluid into the reservoir matrix at different well sections of a horizontal well under real conditions. This improves the accuracy and reliability of drilling fluid invasion tests in horizontal wells and provides a reasonable, feasible, and highly operable experimental test method for scientifically evaluating drilling fluid invasion in the reservoir matrix area during horizontal well drilling.

[0030] Using this drilling fluid invasion test method, the process of drilling fluid invasion into the reservoir matrix in different sections of a horizontal well can be simulated in groups to restore the actual filtration of drilling fluid, ensuring the accuracy and reliability of drilling fluid invasion testing in horizontal wells, and greatly improving people's understanding of the drilling fluid invasion process in the reservoir matrix during horizontal well drilling. Attached Figure Description

[0031] Figure 1 This is the drilling fluid intrusion test system provided in a specific embodiment of the present invention.

[0032] In the picture:

[0033] 1-Injection line; 11-Pressure pump; 12-First pressure regulating valve; 13-First pressure gauge;

[0034] 2-Seepage module; 21-Circulation chamber; 22-Rock mass chamber; 23-Seepage chamber;

[0035] 3-First recycling container;

[0036] 4-Second recycling container;

[0037] 5-Filtrate line; 51-Second pressure regulating valve; 52-Second pressure gauge;

[0038] 6-Return piping. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0040] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0043] like Figure 1As shown, the present invention provides a drilling fluid invasion test system, which includes an injection pipeline 1 and at least two seepage modules 2. A pressure pump 11 is installed on the injection pipeline 1. At least two seepage modules 2 are sequentially arranged on the injection pipeline 1 along its length. Each seepage module 2 has a circulation chamber 21 and a rock mass chamber 22 that are interconnected. The rock mass chamber 22 is used to contain the rock mass to be tested. The circulation chamber 21 has an inlet and an outlet. A seepage hole is opened at the end of the rock mass chamber 22 away from the circulation chamber 21. In two adjacent seepage modules 2, along the flow direction of the liquid in the injection pipeline 1, the outlet of the upstream seepage module 2 is connected to the inlet of the downstream seepage module 2. A first pressure gauge 13 is installed on the injection pipeline 1 at each inlet, and a first pressure regulating valve 12 is installed on the injection pipeline 1 at each outlet. Specifically, the injection pipeline 1 is used to circulate drilling fluid. Since the seepage module 2 has interconnected circulation chambers 21 and rock mass chambers 22 (the rock mass chamber 22 is used to contain the rock mass to be tested), and the seepage module 2 is installed on the injection pipeline 1 with an inlet for fluid input, the seepage module 2 can test the intrusion of drilling fluid into the rock mass to be tested. Because the injection pipeline 1 is equipped with a pressure pump 11, and each circulation chamber 21 is equipped with a first pressure gauge 13 and a first pressure regulating valve 12, the drilling fluid pressure in each circulation chamber 21 can be adjusted according to actual conditions to meet diverse experimental testing needs under different geological conditions. Since this drilling fluid intrusion test system has at least two seepage modules 2, and at least two seepage modules 2 are connected along the injection pipeline... The injection pipeline 1 is arranged sequentially along the length of the pipeline 1, and the outlet of the upstream seepage module 2 is connected to the inlet of the downstream seepage module 2. Therefore, multiple seepage modules 2 are connected through the injection pipeline 1 to form a series system. The liquid in the injection pipeline 1 can enter the circulation chamber 21 sequentially and flow through the test rock in multiple rock chambers 22 under different pressure conditions. Therefore, this drilling fluid invasion test system can simultaneously conduct invasion tests on multiple test rock bodies, thereby simulating the filtration process of drilling fluid into the reservoir matrix at different sections of a horizontal well under real conditions. This improves the accuracy and reliability of drilling fluid invasion tests in horizontal wells and provides a reasonable, feasible, and highly operable experimental test method for scientifically evaluating drilling fluid invasion in the reservoir matrix area during horizontal well drilling.

[0044] The number of seepage modules 2 is determined based on the actual drilling conditions and reservoir characteristics of the horizontal well. Generally, there are no fewer than three seepage modules 2 to ensure complete acquisition of drilling fluid intrusion information throughout the horizontal well. In this embodiment, as... Figure 1As shown, there are three seepage modules 2. Each seepage module 2 has a circulation chamber 21 and a rock mass chamber 22. The circulation chamber 21 is equipped with an inlet and an outlet. The injection pipeline 1 connects the three seepage modules 2 horizontally in series through the inlet and outlet of the circulation chamber 21. The rock mass chamber 22 is located below the circulation chamber 21. The operator adjusts and detects the pressure in each circulation chamber 21 through the pressurization pump 11 and the first pressure regulating valve 12, so that the pressure difference between each circulation chamber 21 and the pressure at the outlet of the rock mass chamber 22 reaches their respective preset pressure difference P. Then, the drilling fluid in the circulation chamber 21 will invade (filter out) the rock mass to be tested in the rock mass chamber 22 under the action of the preset pressure difference P.

[0045] Furthermore, the space of the rock cavity 22 matches the shape of the rock mass to be tested, and the rock mass to be tested is confined within the rock cavity 22, thereby ensuring the accuracy of the entire invasion test and avoiding insufficient pressure during drilling fluid invasion due to gaps between the rock cavity 22 and the rock mass to be tested. In this embodiment, the rock mass to be tested can be selected according to the physical properties of the reservoir matrix in each well section. The rock mass to be tested can be cut and ground using outcrop cores or artificial cores. For uncemented or weakly cemented loose reservoirs, the rock mass to be tested can also be prepared by grinding and pressing reservoir rock cuttings to match the rock cavity 22. Since the shape of the rock mass to be tested matches the space of the rock cavity 22, and the rock cavity 22 confines and accommodates the rock mass to be tested, the drilling fluid pressure in the circulation chamber 21 can be fully applied to the rock mass to be tested, preventing drilling fluid from flowing out from the gap between the circulation chamber 21 and the rock mass to be tested, thus avoiding inaccurate experimental results.

[0046] In this embodiment, to facilitate the observation of the intrusion results, the outer wall of the rock cavity 22 is entirely made of a pressure-resistant transparent material, such as polycarbonate, polyvinyl chloride, and polyurethane plastics. In another embodiment, the outer wall of the rock cavity 22 is provided with several visualization windows, which are also made of a pressure-resistant transparent material. This visualization design facilitates the observation and recording of the seepage depth of drilling fluid in the rock mass under test by the operators.

[0047] Furthermore, such as Figure 1As shown, the seepage module 2 also includes a seepage chamber 23, which is connected to the rock mass cavity 22 through seepage holes. The seepage chamber 23 is used to contain formation fluids. The outlet of the seepage chamber 23 is equipped with a second pressure regulating valve 51 and a second pressure gauge 52. Specifically, the seepage chamber 23 is located below the rock mass cavity 22. The seepage chamber 23 is used to contain formation fluids to simulate the reservoir matrix environment under real conditions, thereby improving the reliability of the experiment. It is understood that the type of formation fluid needs to be selected according to the actual situation. The second pressure regulating valve 51 cooperates with the first pressure regulating valve 12 so that the pressure difference between the circulation chamber 21 and the pressure at the outlet of the rock mass cavity 22 can reach the preset pressure difference P more quickly and accurately. In this embodiment, since the circulation chamber 21 is connected to the seepage chamber 23 through the rock cavity 22, the preset pressure difference P is generated by the difference between the actual pressure inside the circulation chamber 21 and the seepage chamber 23. The second pressure regulating valve 51 is used to regulate the pressure in the seepage chamber 23, and the second pressure gauge 52 is used to detect the pressure in the seepage chamber 23. Therefore, during the experiment, the operator can adjust the first pressure regulating valve 12 and the second pressure regulating valve 51 according to the filtration pressure difference between the bottom hole pressure and the formation pressure during the actual drilling process, so that the pressure difference between the circulation chamber 21 and the seepage chamber 23 reaches the filtration pressure difference in the actual drilling, that is, the preset pressure difference P mentioned above.

[0048] In this embodiment, the seepage module 2 is a long cylindrical structure. The circulation chamber 21, the rock mass chamber 22, and the seepage chamber 23 are connected sequentially along the length of the seepage module 2. The circulation chamber 21 and the rock mass chamber 22 are connected through seepage holes, and the rock mass chamber 22 and the seepage chamber 23 are connected through seepage holes. The injection pipeline 1 delivers drilling fluid to the circulation chamber 21 through the inlet under the action of the pressurization pump 11. The pressure difference between the circulation chamber 21 and the seepage chamber 23 can be adjusted by the first pressure regulating valve 12 and the second pressure regulating valve 51. Thus, the drilling fluid in the circulation chamber 21 can seep from one end of the rock mass to be tested to the other end under the action of the pressure difference.

[0049] like Figure 1As shown, the drilling fluid invasion test system also includes a second recovery container 4. The outlet of the seepage chamber 23 is connected to a filter pipe 5. The outlet of the seepage chamber 23 is connected to the interior of the second recovery container 4 through the filter pipe 5. The second recovery container 4 is used to recover and measure formation fluid. In this embodiment, before the invasion test, the rock mass to be tested is also saturated with formation fluid to restore the true situation of the reservoir matrix. The second recovery container 4 is an open tank, and the seepage chamber 23 plays the role of buffering the migration of formation fluid. When the experiment starts, the drilling fluid in the circulation chamber 21 will seep into the rock mass to be tested under the action of the pressure difference between the circulation chamber 21 and the seepage chamber 23. The formation fluid in the rock mass to be tested will migrate due to the influence of drilling fluid invasion. After flowing through the seepage chamber 23 and the filter pipe 5, it enters the second recovery container 4. Therefore, the operator can measure and analyze the amount of drilling fluid invasion based on the amount of formation fluid in the second recovery container 4.

[0050] Furthermore, such as Figure 1 As shown, the drilling fluid intrusion test system also includes a return pipe 6 and a first recovery container 3. The return pipe 6 is connected to the end of the injection pipe 1, and the injection pipe 1 is connected to the interior of the first recovery container 3 through the return pipe 6. The first recovery container 3 is used to recover the drilling fluid returned from the circulation chamber 21. In this embodiment, the return pipe 6 is connected to the injection pipe 1 at the outlet of the end circulation chamber 21. Under the action of the pressurized pump 11 on the injection pipe 1, the drilling fluid transported in the injection pipe 1 will flow into each circulation chamber 21 in sequence, and then flow back to the first recovery container 3 through the return pipe 6. The outlet of the first recovery container 3 is connected to the injection pipe 1, so the recovered drilling fluid will continue to flow into the circulation chamber 21 through the injection pipe 1, thereby facilitating the reuse of drilling fluid.

[0051] This embodiment also provides a drilling fluid invasion test method. This drilling fluid invasion test method uses the aforementioned drilling fluid invasion test system and includes the following steps: S1, loading each rock mass to be tested into the rock mass cavity 22; S2, filling the circulation cavity 21 of each seepage module 2 with formation fluid; S3, starting the pressurization pump 11 and inputting drilling fluid into the injection pipeline 1; S4, adjusting the opening of each first pressure regulating valve 12 so that the pressure difference between the circulation cavity 21 and the pressure at the outlet of the rock mass cavity 22 reaches a preset pressure difference P; S5, observing the penetration depth of the drilling fluid. Specifically, this drilling fluid invasion test method can simulate the invasion process of drilling fluid into the reservoir matrix in different sections of a horizontal well in groups, to restore the filtration loss of drilling fluid under real conditions, ensuring the accuracy and reliability of horizontal well drilling fluid invasion testing, and greatly improving people's understanding of the drilling fluid invasion process in the reservoir matrix during horizontal well drilling.

[0052] In this embodiment, before loading the rock mass to be tested into the rock mass cavity 22 in step S1, it is necessary to determine the number of rock masses to be tested in the required test well section based on the actual conditions such as the physical properties of the reservoir matrix, the length of the well section, and the formation pressure during the drilling process. Then, according to the physical properties of the reservoir matrix in each well section, outcrops with conditions similar to the actual reservoir matrix are selected to cut the rock mass to be tested, or the rock mass to be tested is artificially pressed to be equivalent to the actual reservoir matrix conditions. It should be noted that the shape of the rock mass to be tested matches the space of the rock mass cavity 22, and the rock mass to be tested is limited and installed in the rock mass cavity 22.

[0053] Further, step S1 specifically includes: according to the contact sequence of drilling fluid during the actual drilling process, each rock mass to be tested is sequentially installed in the rock mass cavity 22 of each seepage module 2 along the flow direction of drilling fluid in the injection pipeline 1; in this embodiment, the drilling fluid intrusion test system is equipped with three seepage modules 2. Before conducting the experiment, the staff first arranges the three rock masses to be tested according to the flow direction of drilling fluid in the annulus during the actual drilling process, and sequentially installs the three rock masses to be tested into the rock mass cavity 22 of the three seepage modules 2 along the flow sequence of drilling fluid in the injection pipeline 1, so as to ensure that the contact sequence of drilling fluid with the rock mass to be tested when flowing through each seepage module 2 is the same as that under actual working conditions.

[0054] In this embodiment, the seepage module 2 further includes a seepage chamber 23, which is connected to the rock cavity 22 through a seepage hole. Before starting the pressurization pump 11, the operator infiltrates formation fluid into the rock mass to be tested, and simultaneously fills the circulation chamber 21 and seepage chamber 23 of each seepage module 2 with formation fluid, and closes the second pressure regulating valve 51 at the outlet of the seepage chamber 23. Then, the operator injects drilling fluid into the injection pipeline 1, opens each first pressure regulating valve 12 to its maximum, and starts the pressurization pump 11 to pump drilling fluid, displacing the formation fluid in all circulation chambers 21. After the injection pipeline 1 and each circulation chamber 21 are filled with drilling fluid, the flow rate of the pressurization pump 11 is increased and the opening of each first pressure regulating valve 12 and second pressure regulating valve 51 is adjusted so that the pressure difference between the circulation chamber 21 and the seepage chamber 23 reaches a preset pressure difference P. The opening of the first pressure regulating valve 12 and the second pressure regulating valve 51 is kept constant, and the pressurization pump 11 is maintained at its maximum pressure. The flow rate of the pressure pump 11 remains constant. During this process, part of the drilling fluid in the circulation chamber 21 will seep from the top to the bottom of the rock mass under the action of the preset pressure difference P. The formation fluid inside the rock mass under test will be affected by the intrusion of the drilling fluid and will move. After flowing through the seepage chamber 23 and the filter pipe 5, it will enter the second recovery container 4. At the same time, another part of the drilling fluid in the circulation chamber 21 will flow back to the first recovery container 3 through the return pipe 6 under the drive of the pressure pump 11, so as to repeatedly fill the circulation chamber 21 with drilling fluid, thereby ensuring the continuous seepage of drilling fluid.

[0055] To improve the identification of drilling fluid and facilitate the observation of the penetration depth of drilling fluid in the rock mass to be tested, step S3 before starting the pressurization pump 11 also includes: adding dyeing material to the drilling fluid. During the experiment, the staff can observe and record the penetration depth of drilling fluid in the pores of the rock mass to be tested in real time through the viewing window on the outer wall of the visualization rock cavity 22.

[0056] Furthermore, prior to step S1, a transparent coating with the opposite polarity to the drilling fluid is applied to the surface of the rock mass to be tested. This transparent coating prevents the capillary force between the rock mass and the inner wall of the rock cavity 22 from affecting the penetration depth of the drilling fluid, thereby ensuring the accuracy of the experimental results. In this embodiment, drilling fluids are classified into water-based drilling fluids and oil-based drilling fluids according to the different molecular structural characteristics of the chemical components contained in the drilling fluid. Water-based drilling fluid is used in this experiment, and the surface of the rock mass to be tested is uniformly coated with an oil-based transparent coating.

[0057] Specifically, the experimental time is determined according to the actual situation. After the experiment, the staff will draw a curve showing the relationship between the penetration depth of drilling fluid and time based on the data observed and recorded earlier. In addition, the staff can also cut the rock mass to be tested that has been penetrated by drilling fluid into several segments and use scanning electron microscopy to analyze the damage mechanism and degree of damage of drilling fluid penetration into the rock mass to be tested in each segment.

[0058] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A drilling fluid intrusion test system, characterized in that, include: An injection pipeline (1) is provided with a pressure pump (11). At least two seepage modules (2) are arranged sequentially along the length of the injection pipeline (1). The seepage module (2) has a circulation chamber (21) and a rock mass chamber (22) that are interconnected. The rock mass chamber (22) is used to contain the rock mass to be tested. The circulation chamber (21) has an inlet and an outlet. A seepage hole is opened at one end of the rock mass chamber (22) away from the circulation chamber (21). In two adjacent seepage modules (2), along the flow direction of the liquid in the injection pipe (1), the outlet of the upstream seepage module (2) is connected to the inlet of the downstream seepage module (2). A first pressure gauge (13) is provided on the injection pipe (1) at each inlet, and a first pressure regulating valve (12) is provided on the injection pipe (1) at each outlet.

2. The drilling fluid invasion test system according to claim 1, characterized in that, The seepage module (2) further includes a seepage cavity (23), which is connected to the rock mass cavity (22) through the seepage hole. The seepage cavity (23) is used to contain formation fluids. The outlet of the seepage chamber (23) is provided with a second pressure regulating valve (51) and a second pressure gauge (52).

3. The drilling fluid invasion test system according to claim 2, characterized in that, The drilling fluid intrusion test system also includes a second recovery container (4), and the outlet of the seepage chamber (23) is connected to a filtrate pipeline (5). The outlet of the seepage chamber (23) is connected to the interior of the second recovery container (4) through the filtrate pipeline (5).

4. The drilling fluid invasion test system according to claim 1, characterized in that, The drilling fluid intrusion test system also includes a return pipe (6) and a first recovery container (3). The return pipe (6) is connected to the end of the injection pipe (1), and the injection pipe (1) is connected to the interior of the first recovery container (3) through the return pipe (6).

5. The drilling fluid invasion test system according to claim 1, characterized in that, The space of the rock cavity (22) matches the shape of the rock mass to be tested.

6. The drilling fluid invasion test system according to any one of claims 1-5, characterized in that, A viewing window is provided on the outer wall of the rock cavity (22).

7. A drilling fluid invasion test method, characterized in that, Using the drilling fluid invasion testing system as described in any one of claims 1-5, the following steps are included: S1. Each of the rock masses to be tested is loaded into the rock mass cavity (22); S2. The circulation chamber (21) of each of the seepage modules (2) is filled with formation fluid; S3. Start the pressurization pump (11) and input drilling fluid into the injection pipeline (1); S4. Adjust the opening of each of the first pressure regulating valves (12) so that the pressure difference between the pressure in each of the circulation chambers (21) and the pressure at the outlet of the rock mass chamber (22) reaches the preset pressure difference P; S5. Observe the penetration depth of the drilling fluid.

8. The drilling fluid invasion test method according to claim 7, characterized in that, Step S1 specifically includes: According to the contact sequence of the drilling fluid during the actual drilling process, each of the rock masses to be tested is sequentially installed in the rock cavity (22) of each of the seepage modules (2) along the flow direction of the drilling fluid in the injection pipeline (1).

9. The drilling fluid invasion test method according to claim 7, characterized in that, Before starting the pressurization pump (11) in step S3, the following is also included: A dyeing material is added to the drilling fluid.

10. The drilling fluid invasion test method according to claim 7, characterized in that, Step S1 is preceded by: A transparent coating with the opposite polarity to the drilling fluid is applied to the surface of the rock mass to be tested.

Images