A targeted drilling mud annular film formation simulation device and method

Abstract

The present invention discloses a device and method for simulating annular film formation of mud in targeted drilling. The device includes a support, a simulated well body and a sealing sleeve. The simulated well body is arranged on the support and has a pitch stroke. The simulated well body includes a first well cavity, a second well cavity, an annular filtration cavity and a mud film permeability test cavity. The annular filtration cavity is a rigid filter mesh-shaped semi-cylinder structure. The mud film permeability test cavity is a rigid semi-cylinder structure, wherein a filter mesh structure is provided on one half of the cylinder. The first end of the annular filtration cavity is connected to the first well cavity, and the second end is connected to the open end of the second well cavity. The sealing sleeve covers the annular filtration cavity. The present invention is applied to the field of targeted drilling. The simulated formation material can be replaced to realize the simulation of different formation conditions, and the generation test of spatial annular mud film during targeted drilling at different angles and under different mud pressure conditions can be performed. The formation of mud film in spatial dimension in targeted drilling and the permeability test of mud film in different spatial regions can be more realistically simulated.

Description

Technical Field

[0001] The invention relates to the technical field of targeted drilling, in particular to a device and method for simulating circumferential film formation of targeted drilling mud. Background Art

[0002] Targeted drilling technology controls the rotation and tilt angle of the drill bit to make the drill bit drill along the designed trajectory, achieving drilling trajectories in different directions such as curves, horizontal and vertical directions. An important reason for the instability of the well wall during targeted drilling is that a large amount of free water in the mud enters the formation, causing the hydrophilic substances in the formation to quickly combine with water, reducing the strength of the soil or rock in the formation, and further causing in-hole accidents such as drill sticking. The mud film formed by the mud on the well wall can reduce the penetration of free water in the mud, which plays an important role in maintaining the stability of the well wall. The permeability of the mud film is an important indicator for evaluating the performance of the mud film. It is generally believed that the thinner and denser the mud film, the lower the permeability, which can more effectively prevent the free water in the mud from diffusing into the formation.

[0003] At present, the circular plane mud film formed vertically by mud is mostly obtained based on the traditional static pressure filter loss instrument. The method for preparing the spatial annular mud film formed during drilling and testing the permeability of the spatial annular mud film is still unclear, and there is no standard in the industry. Therefore, the development of a device for preparing the annular mud film and a test and analysis method for the permeability of the annular mud film that can simulate drilling at different borehole inclination angles and different formation conditions is of great significance to maintaining the stability of the well wall during targeted drilling, reducing accidents in the hole, and improving drilling efficiency. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a targeted drilling mud annular film formation simulation device and method, which can more realistically simulate the formation of mud film in drilling in the spatial dimension, and provide a basis for the formation process and mechanism of mud film in drilling.

[0005] To achieve the above-mentioned purpose, the present invention provides a targeted drilling mud annular film formation simulation device, comprising a bracket, a simulated well body and a sealing sleeve, wherein the simulated well body is arranged on the bracket, and the simulated well body has a pitching stroke on the bracket;

[0006] The simulated well body comprises a first well cavity, a second well cavity, an annular filtration cavity and a mud film permeability test cavity, the annular filtration cavity is an openable rigid filter mesh semi-closed cylinder structure, and the first well cavity and the second well cavity are both cylindrical structures with one end open;

[0007] The first end of the annular filtration cavity is sealed and connected to the opening end of the first well cavity, the second end of the annular filtration cavity is sealed and connected to the opening end of the second well cavity, and the inner diameter of the annular filtration cavity is larger than the inner diameters of the first well cavity and the second well cavity;

[0008] The mud film permeability test cavity is an openable rigid semi-closed cylinder structure, and the middle part of the half cylinder has a filter structure. In the mud film permeability test cavity: the inner diameter of the part without the filter structure is the same as the first well cavity and the second well cavity, and the inner diameter of the part with the filter structure is the same as the annular filtration loss cavity;

[0009] The sealing sleeve is sleeved on the opening ends of the first well cavity and the second well cavity, and the sealing sleeve covers the annular filtration cavity;

[0010] A pressurizing mechanism and a liquid adding mechanism are provided on the first well cavity or the second well cavity, and a water filtering mechanism is provided on the sealing sleeve.

[0011] In one embodiment, the annular filtration chamber includes two rigid semi-cylindrical filter screens;

[0012] The first side edges of the two rigid semi-cylinder filter screens are hingedly connected by a hinge, and the second side edges of the two rigid semi-cylinder filter screens are detachably connected by a buckle or a latch.

[0013] In one embodiment, the mud membrane permeability test chamber includes two rigid semi-cylinders, one of which has the filter structure;

[0014] The first side edges of the two rigid semi-cylinders are hingedly connected by a hinge, and the second side edges of the two rigid semi-cylinders are detachably connected by a buckle or a latch.

[0015] In one embodiment, a first annular groove is provided at the opening end of the first well cavity, and a first sealing ring is provided in the first annular groove;

[0016] A second annular groove is provided at the opening end of the second well cavity, and a second sealing ring is provided in the second annular groove;

[0017] The first end of the annular filtration cavity is embedded in the first annular groove and presses the first sealing ring, and the second end of the annular filtration cavity is embedded in the second annular groove and presses the second sealing ring.

[0018] In one embodiment, a third annular groove is provided on the outer wall of the first well cavity, and a third sealing ring is provided in the third annular groove;

[0019] The first end of the sealing sleeve is connected to the first well cavity through a plurality of circumferentially distributed first bolts, and presses the third sealing ring;

[0020] A fourth annular groove is provided on the outer wall of the second well cavity, and a fourth sealing ring is provided in the fourth annular groove;

[0021] The second end of the sealing sleeve is connected to the second well cavity through a plurality of circumferentially distributed second bolts, and compresses the fourth sealing ring.

[0022] In one embodiment, the pressurizing mechanism includes a gas storage bottle, an air intake valve and an air intake pipe;

[0023] One end of the air inlet pipe is connected to the gas storage bottle, and the other end passes through the center of the closed end of the first well cavity or the second well cavity and communicates with the well cavity of the simulated well body;

[0024] The intake valve is arranged on the intake pipe.

[0025] In one embodiment, the liquid adding mechanism includes a mud pool, a mud injection valve and a mud pipe;

[0026] One end of the mud pipe is connected to the mud pool, and the other end passes through the first well cavity or the second well cavity and communicates with the well cavity of the simulated well body;

[0027] The mud injection valve is arranged on the mud pipe.

[0028] In one embodiment, the water filtering mechanism includes a water filtering pipe and a water filtering measuring cylinder;

[0029] One end of the water filter tube is connected to the cylinder wall at the bottom of the sealing sleeve and communicates with the inner cavity of the sealing sleeve, and the other end of the water filter tube is located directly above the water filter measuring cylinder.

[0030] In one embodiment, the targeted drilling mud annular film formation simulation device further includes a host computer and a plurality of seepage pressure sensors;

[0031] The seepage pressure sensor is arranged on the inner wall of the annular filtration cavity, and there are a plurality of evenly distributed seepage pressure sensors in the same circumferential direction of the annular filtration cavity, and there are also a plurality of evenly distributed seepage pressure sensors in the axial direction of the annular filtration cavity;

[0032] Each of the seepage pressure sensors is connected to the host computer via a cable, and the cable passes through the sealing sleeve, the first well cavity or the second well cavity.

[0033] To achieve the above object, the present invention further provides a targeted drilling mud annular film forming method, using the above-mentioned targeted drilling mud annular film forming simulation device, the targeted drilling mud annular film forming method comprises the following steps:

[0034] Step 101, after arranging pressure seepage sensors uniformly distributed circumferentially and axially on the inner wall of the annular fluid loss cavity, filling the inner wall of the annular fluid loss cavity with a simulated formation required for the test, so that the inner wall of the simulated formation is flush with the inner walls of the first well cavity and the second well cavity;

[0035] Step 102, sealingly connecting the annular filtration cavity with the first well cavity and the second well cavity to form a simulated well body and connecting the cable between the pressure seepage sensor and the host computer;

[0036] Step 103, after installing the sealing sleeve, the pressurizing mechanism, the liquid adding mechanism and the water filtering mechanism, the pitch angle of the simulated well body on the support is adjusted to the drilling angle required for the test simulation;

[0037] Step 104, setting the output pressure of the pressurizing mechanism and the time interval for the upper computer to collect pressure data, injecting the mud required for the test prepared in advance into the wellbore of the simulated well body through the liquid adding mechanism, and stopping the injection after the entire wellbore is filled;

[0038] Step 105, start the pressurizing mechanism and open the water filtering mechanism to start the film forming test, and start timing at the same time;

[0039] Step 106, after the film forming test is completed, the pressurizing mechanism is closed and the excess gas is released, the sealing sleeve is removed and the annular filtration cavity with the simulated formation and the annular mud film is taken out;

[0040] Step 107, after cutting the simulated formation and the annular mud film into two semi-cylindrical structure units along the opening line of the annular filtration cavity, the annular filtration cavity is opened, and two simulated formation units with mud films are taken out respectively, and the test data are recorded;

[0041] Step 108, after changing the performance parameters of the simulated formation, perform steps 101 to 107 again to obtain different test schemes and record test data, and analyze the characteristics of the spatial annular mud film and its influencing factors;

[0042] The analysis of the spatial annular mud film characteristics and influencing factors specifically includes the following steps:

[0043] Step 201, cutting two simulated formation units with mud film obtained under the condition of a set drilling inclination angle into multiple mud film formation samples along the axial direction, and the size of the mud film formation samples is the same as the size of the filter structure on the mud film permeability test cavity;

[0044] Step 202, after selecting a mud film formation sample and filling it on the inner wall of the filter structure of the mud film permeability test cavity, the mud film permeability test cavity is sealed and connected with the first well cavity and the second well cavity to form a simulated well body and connect the cable between the pressure seepage sensor and the host computer;

[0045] Step 203, after installing the sealing sleeve, the pressurizing mechanism, the liquid adding mechanism and the water filtering mechanism, adjust the pitch angle of the simulated well body on the bracket to make the simulated well body horizontal;

[0046] Step 204, setting the output pressure of the pressurizing mechanism and the time interval for the upper computer to collect pressure data, injecting water into the well cavity of the simulated well body through the liquid injection mechanism, and stopping the injection after the entire well cavity is filled;

[0047] Step 205, start the pressurizing mechanism and open the water filtering mechanism to start the filtration test, and start the timing at the same time;

[0048] Step 206, after the filtration test is completed, the pressurizing mechanism is closed and the excess gas is released, and then the mud film formation sample is taken out and its permeability is recorded;

[0049] Step 207, select the next mud film formation sample and repeat steps 202 to 206 until all mud film formation samples have completed the permeability test, so as to analyze the permeability characteristics of mud films in different spatial regions.

[0050] Compared with the prior art, the present invention has the following beneficial technical effects:

[0051] 1. The present invention can not only flexibly replace the simulated formation materials to simulate different formation conditions, and conduct spatial annular mud film generation tests during drilling under different angles and different mud pressure conditions, but also can more realistically simulate the formation of mud film in the spatial dimension during targeted drilling, and can also monitor the changes in pore water pressure generated by mud loss in different directions, thus providing a basis for the mud film formation process and mechanism during targeted drilling;

[0052] 2. The present invention sets the simulated well body as a split structure and cooperates with a sealing sleeve so that the free water in the well cavity can only flow out from the annular filtration cavity, which not only facilitates the assembly of the film forming device and the replacement of the simulated formation material, but also simplifies the structure of the film forming device without using a sealing kettle [1][2], thereby reducing the cost;

[0053] 3. The present invention sets the annular filtration cavity as an openable rigid sieve-like semi-closed cylinder structure, so that the simulated formation and the annular mud film can be cut into two pieces along the opening line of the annular filtration cavity before taking out the mud film, that is, the annular mud film is cut into a surface shape and then taken out, effectively avoiding damage to the mud film;

[0054] 4. The mud film permeability test chamber provided in the present invention can perform permeability tests on mud films generated in different spatial regions respectively, providing a basis for studying the generation mechanism of spatial annular mud films and the variation law of permeability characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0056] Figure 1 It is an overall schematic diagram of a targeted drilling mud annular film-forming simulation device in an embodiment of the present invention;

[0057] Figure 2 Schematic diagram of the structure of the annular filtration chamber in an embodiment of the present invention.

[0058] Figure numbers: first well cavity 1, first end cover 101, second well cavity 2, second end cover 201, annular filtration chamber 3, rigid semi-cylindrical filter screen 301, sealing sleeve 4, first bolt 401, second bolt 402, first sealing ring 5, second sealing ring 6, third sealing ring 7, fourth sealing ring 8, gas storage bottle 9, air inlet valve 10, air inlet pipe 11, mud pool 12, mud injection valve 13, mud pipe 14, water filter pipe 15, water filter measuring cylinder 16, host computer 17, seepage pressure sensor 18, cable 19.

[0059] 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

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 creative work are within the scope of protection of the present invention.

[0061] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0062] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0063] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0065] like Figure 1 The figure shows a targeted drilling mud annular film formation simulation device disclosed in this embodiment, which mainly includes a bracket, a simulated well body and a sealing sleeve 4. The bracket is a pitch bracket, including a fixed base and a support hinged on the base, and an oil cylinder is hinged between the base and the support. As the oil cylinder is extended and retracted, the support performs a pitching action on the base. The simulated well body is fixed on the support, that is, the simulated well body has the freedom to follow the pitch of the support on the bracket, so as to simulate the generation environment of the spatial annular mud film when drilling under different angle conditions.

[0066] In this embodiment, the simulated well body includes a first well cavity 1, a second well cavity 2, an annular filtration cavity 3 and a mud film permeability test cavity. The annular filtration cavity 3 is an openable rigid mesh-like semi-closed cylinder structure. The first well cavity 1 and the second well cavity 2 are both cylindrical structures with one end open. The first end of the annular filtration cavity 3 is sealed and connected to the open end of the first well cavity 1, and the second end of the annular filtration cavity 3 is sealed and connected to the open end of the second well cavity 2. The inner diameter of the annular filtration cavity 3 is larger than the inner diameters of the first well cavity 1 and the second well cavity 2. The sealing sleeve 4 is sleeved on the open ends of the first well cavity 1 and the second well cavity 2, and the sealing sleeve 4 covers the annular filtration cavity 3. During the test, the annular filtration cavity 3 can be opened and the simulated formation required for the test can be filled on the inner wall of the annular filtration cavity 3, thereby facilitating the operation while ensuring the consistency of the thickness of the simulated formation at each position of the annular filtration cavity 3. A pressurizing mechanism and a liquid adding mechanism are provided on the first well cavity 1 or the second well cavity 2, and a water filtering mechanism is provided on the sealing sleeve 4. The liquid adding mechanism is used to inject mud into the well cavity of the simulated well body, the pressurizing mechanism is used to adjust the well cavity pressure of the simulated well body, and the water filtering mechanism is used to discharge free water seeping from the simulated formation.

[0067] The mud film permeability test chamber is an openable rigid semi-cylinder structure, and the middle part of one half of the cylinder has a filter structure. The axial length of the mud film permeability test chamber is the same as that of the annular filtration chamber 3. Specifically, the mud film permeability test chamber includes two rigid semi-cylinders, one of which has a filter structure. The first side edges of the two rigid semi-cylinders are hinged by a hinge, and the second side edges of the two rigid semi-cylinders are detachably connected by a buckle or a pin. In the mud film permeability test chamber: the inner diameter of the part without the filter structure is the same as the inner diameter of the first well cavity and the second well cavity, and the inner diameter of the filter structure part is the same as the inner diameter of the annular filtration chamber. After completing the mud film formation experiment, the simulated formation with mud film in the annular filtration cavity 3 is cut into multiple parts along the axial direction according to the size of the filter structure on the mud film permeability test cavity, and each simulated formation sample with mud film is placed on the inner wall of the filter structure of the mud film permeability test cavity in turn, and then the annular filtration cavity 3 is replaced by the mud film permeability test cavity, so that the targeted drilling mud annular film formation simulation device can be used for mud film permeability testing, thereby analyzing the permeability characteristics of mud films at different spatial positions.

[0068] refer to Figure 2 The annular filtration cavity 3 includes two rigid semi-cylindrical filter screens 301, the first sides of the two rigid semi-cylindrical filter screens 301 are hinged by a hinge, and the second sides of the two rigid semi-cylindrical filter screens 301 are detachably connected by a buckle or a latch. In this embodiment, two mutually hinged rigid semi-cylindrical filter screens 301 are used to form an annular filtration cavity 3, which is not only convenient for filling the simulated formation, but also can directly use the opening of the annular filtration cavity 3 to cut the annular simulated formation and the mud film after the mud film is generated, that is, the annular mud film is cut into a surface shape and then taken out, thereby effectively avoiding damage to the mud film.

[0069] In this embodiment, a first annular groove is provided at the open end of the first well cavity 1, and a first sealing ring 5 is provided in the first annular groove; a second annular groove is provided at the open end of the second well cavity 2, and a second sealing ring 6 is provided in the second annular groove. The first end of the annular filtration cavity 3 is embedded in the first annular groove and the first sealing ring 5 is pressed tightly; the second end of the annular filtration cavity 3 is embedded in the second annular groove and the second sealing ring 6 is pressed tightly. At the same time, a third annular groove is provided on the outer wall of the first well cavity 1, and a third sealing ring 7 is provided in the third annular groove. The first end of the sealing sleeve 4 is connected to the first well cavity 1 through a plurality of circumferentially distributed first bolts 401, and the third sealing ring 7 is pressed tightly. A fourth annular groove is provided on the outer wall of the second well cavity 2, and a fourth sealing ring 8 is provided in the fourth annular groove. The second end of the sealing sleeve 4 is connected to the second well cavity 2 through a plurality of circumferentially distributed second bolts 402, and the fourth sealing ring 8 is pressed tightly. By setting the simulated well body as a split structure and cooperating with the sealing sleeve 4, the free water in the well cavity can only flow out from the annular filtration cavity 3, which not only facilitates the assembly of the film forming device and the replacement of the simulated formation material, but also simplifies the structural composition of the film forming device without using a sealing kettle, thereby reducing costs. Among them, the mud film permeability test cavity is respectively provided with annular protrusions corresponding to the first annular groove and the second annular groove, so that the mud film permeability test cavity can replace the annular filtration cavity 3 to achieve a sealed connection with the first well cavity 1 and the second well cavity 2.

[0070] In the specific implementation process, the closed end of the first well cavity 1 is a first end cap 101 that is connected by a thread and is detachable, and the closed end of the second well cavity 2 is a second end cap 201 that is connected by a thread and is detachable. The first well cavity 1 and the second well cavity 2 are set as a split structure to facilitate the cleaning of the first well cavity 1 and the second well cavity 2. The pressurizing mechanism includes a gas cylinder 9, an air inlet valve 10 and an air inlet pipe 11. One end of the air inlet pipe 11 is connected to the gas cylinder 9, and the other end passes through the center position of the first end cap 101 or the second end cap 201 and is connected to the well cavity of the simulated well body. The air inlet valve 10 is arranged on the air inlet pipe 11. By opening the air inlet valve 10, the high-pressure gas in the gas cylinder 9 can be passed into the well cavity of the simulated well body to meet the different formation pressures required by the test. In this embodiment, the formation pressure range that the pressurizing mechanism can provide is 0MPa~5.0MPa.

[0071] In the specific implementation process, the liquid adding mechanism includes a mud pool 12, a mud injection valve 13 and a mud pipe 14. One end of the mud pipe 14 is connected to the mud pool 12, and the other end passes through the first well cavity 1 or the second well cavity 2 and is connected to the well cavity of the simulated well body. The mud injection valve 13 is arranged on the mud pipe 14. By opening the mud injection valve 13, the mud in the mud pool 12 can be passed into the well cavity of the simulated well body.

[0072] In the specific implementation process, the water filtering mechanism includes a water filtering tube 15 and a water filtering measuring cylinder 16. One end of the water filtering tube 15 is connected to the cylinder wall at the bottom of the sealing sleeve 4 and is connected to the inner cavity of the sealing sleeve 4. The other end of the water filtering tube 15 is located directly above the water filtering measuring cylinder 16, so that the free water loss during the test can be measured.

[0073] As a preferred embodiment, the targeted drilling mud annular film formation simulation device also includes a host computer 17 and a plurality of seepage pressure sensors 18. The seepage pressure sensor 18 is arranged on the inner wall of the annular filtration cavity 3, and there are multiple uniformly distributed seepage pressure sensors 18 in the same circumferential direction of the annular filtration cavity 3, and there are multiple uniformly distributed seepage pressure sensors 18 in the axial direction of the annular filtration cavity 3. Each seepage pressure sensor 18 is electrically connected to the host computer 17 through a cable, and the cable 19 passes through the sealing sleeve 4, the first well cavity 1 or the second well cavity 2. The host computer 17 and the seepage pressure sensor 18 can be used to monitor the pressure changes after mud filtration, so as to facilitate the subsequent analysis of test results.

[0074] Based on the above-mentioned targeted drilling mud annular film forming simulation device, this embodiment also discloses a targeted drilling mud annular film forming method, which mainly includes the following steps:

[0075] The annular filtration cavity 3 is opened, and pressure seepage sensors uniformly distributed in the circumferential direction and the axial direction are arranged on the inner wall of the annular filtration cavity 3. Then, a simulated formation with a sand content of 10% is filled on the inner wall of the annular filtration cavity 3, so that the inner wall of the simulated formation is flush with the inner walls of the first well cavity 1 and the second well cavity 2;

[0076] After installing the first sealing ring 5 and the second sealing ring 6, the annular filtration cavity 3 is sealed and connected with the first well cavity 1 and the second well cavity 2 to form a simulated well body, and at the same time, the cable 19 between the pressure seepage sensor and the host computer 17 is connected;

[0077] After installing the third sealing ring 7 and the fourth sealing ring 8, the sealing sleeve 4 is connected and fixed to the first well cavity 1 and the second well cavity 2 by the first bolt 401 and the second bolt 402, and then the pressurizing mechanism, the liquid adding mechanism and the water filtering mechanism are connected respectively, and then the pitch angle of the simulated well body on the bracket is adjusted to the simulated drilling angle of 0° required for the test;

[0078] The output pressure of the pressurizing mechanism is set to 0.5 MPa, and the time interval for collecting pressure data of the host computer 17 is set to 0.1 s. The mud required for the test prepared in advance is injected into the wellbore of the simulated well body through the liquid injection mechanism, and the injection is stopped after the entire wellbore is filled;

[0079] Start the pressurizing mechanism and open the water filtering mechanism to start the test, and start the timing at the same time;

[0080] After the film forming test is completed, the pressurizing mechanism is closed and the excess gas is released, the sealing sleeve 4 is removed and the annular filtration cavity 3 with the simulated formation and the annular mud film is taken out;

[0081] After the simulated formation and the annular mud film are cut into two semi-cylindrical structure units along the opening line of the annular filtration cavity 3, the annular filtration cavity 3 is opened to obtain two simulated formation units with mud films, and the test data are recorded;

[0082] After changing the performance parameters of the simulated formation, the device angle and the set pressure, the above steps were performed again to obtain different test schemes and record the test data, and the characteristics of the spatial annular mud film and the influencing factors were analyzed. For example, the sand content of the simulated formation was changed to 15% and 20%, the formation pressure was changed to 0.6MPa, 0.8MPa, and 1MPa, and the device angle was changed to 30°, 60°, and 90°.

[0083] In the specific implementation process, if the cable 19 needs to pass through the sealing sleeve 4, the cable 19 is led out of the simulated well body in step 3, and then the cable 19 is led out of the sealing sleeve 4 and connected to the host computer during the installation of the sealing sleeve 4 in step 4.

[0084] In this embodiment, the process of analyzing the characteristics of the spatial annular mud film and the influencing factors according to the test record data is specifically as follows:

[0085] After implementing steps 1-7 in the above embodiment under the conditions of the set drilling inclination angle (e.g., 0°, 30°, 60°, and 90°), the two simulated formation units with mud film are evenly divided into 6 mud film formation samples along the axial direction, which are numbered A, B, C, D, E, and F in sequence, and the corresponding spatial position of each sample is recorded;

[0086] Cut the divided mud film formation sample A and fill it into the filter screen of the mud film permeability test cavity, and replace the annular filtration cavity with the mud film permeability test cavity with the mud film formation sample A;

[0087] Set the output pressure of the pressurizing mechanism to 0.7 MPa, inject clean water into the simulated wellbore cavity through the liquid adding mechanism, and stop injecting after the entire wellbore cavity is filled;

[0088] Start the pressurizing mechanism and open the water filtering mechanism to start the test, and time for 5 minutes;

[0089] After 5 minutes, the pressurizing mechanism was closed and the excess gas was released, and the mud film formation sample A was taken out to end the permeability test, and the permeability of sample A within 5 minutes was recorded;

[0090] The above operation is repeated to complete the permeability test of the remaining mud film formation samples B, C, D, E and F, so that the permeability characteristics of the mud films at different spatial positions can be analyzed.

[0091] Based on the above test steps, we can also think of setting test plans with different formation pressures, formation pressure fluctuations, and different simulated formations. We can also think of conducting scanning electron microscope tests on annular mud films to explore the microscopic morphology and structural characteristics of the annular mud films.

[0092] The above description is only a preferred embodiment of the present invention, and does not limit the protection scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the protection scope of the present invention.

Claims

1. A targeted drilling mud annular film formation simulation device, characterized in that: It comprises a support, a simulated well body and a sealing sleeve, wherein the simulated well body is arranged on the support, and the simulated well body has a pitching stroke on the support; The simulated well body comprises a first well cavity, a second well cavity, an annular filtration cavity and a mud film permeability test cavity, the annular filtration cavity is an openable rigid filter mesh semi-closed cylinder structure, and the first well cavity and the second well cavity are both cylindrical structures with one end open; The first end of the annular filtration cavity is sealed and connected to the opening end of the first well cavity, the second end of the annular filtration cavity is sealed and connected to the opening end of the second well cavity, and the inner diameter of the annular filtration cavity is larger than the inner diameters of the first well cavity and the second well cavity; The mud film permeability test cavity is an openable rigid semi-closed cylinder structure, and the middle part of the half cylinder has a filter structure. In the mud film permeability test cavity: the inner diameter of the part without the filter structure is the same as the first well cavity and the second well cavity, and the inner diameter of the part with the filter structure is the same as the annular filtration loss cavity; The sealing sleeve is sleeved on the opening ends of the first well cavity and the second well cavity, and the sealing sleeve covers the annular filtration cavity; A pressurizing mechanism and a liquid adding mechanism are provided on the first well cavity or the second well cavity, and a water filtering mechanism is provided on the sealing sleeve.

2. The targeted drilling mud annular film formation simulation device according to claim 1, characterized in that: The annular filtration chamber includes two rigid semi-cylindrical filter screens; The first side edges of the two rigid semi-cylinder filter screens are hingedly connected by a hinge, and the second side edges of the two rigid semi-cylinder filter screens are detachably connected by a buckle or a latch.

3. The targeted drilling mud annular film formation simulation device according to claim 1, characterized in that: The mud membrane permeability test chamber comprises two rigid semi-cylinders, one of which has the filter structure; The first side edges of the two rigid semi-cylinders are hingedly connected by a hinge, and the second side edges of the two rigid semi-cylinders are detachably connected by a buckle or a latch.

4. The targeted drilling mud annular film formation simulation device according to claim 1, characterized in that: A first annular groove is provided at the opening end of the first well cavity, and a first sealing ring is provided in the first annular groove; A second annular groove is provided at the opening end of the second well cavity, and a second sealing ring is provided in the second annular groove; The first end of the annular filtration cavity is embedded in the first annular groove and presses the first sealing ring, and the second end of the annular filtration cavity is embedded in the second annular groove and presses the second sealing ring.

5. The targeted drilling mud annular film formation simulation device according to any one of claims 1 to 4, characterized in that: A third annular groove is provided on the outer wall of the first well cavity, and a third sealing ring is provided in the third annular groove; The first end of the sealing sleeve is connected to the first well cavity through a plurality of circumferentially distributed first bolts, and presses the third sealing ring; A fourth annular groove is provided on the outer wall of the second well cavity, and a fourth sealing ring is provided in the fourth annular groove; The second end of the sealing sleeve is connected to the second well cavity through a plurality of circumferentially distributed second bolts, and compresses the fourth sealing ring.

6. The targeted drilling mud annular film formation simulation device according to any one of claims 1 to 4, characterized in that: The pressurizing mechanism includes a gas storage bottle, an air intake valve and an air intake pipe; One end of the air inlet pipe is connected to the gas storage bottle, and the other end passes through the center of the closed end of the first well cavity or the second well cavity and communicates with the well cavity of the simulated well body; The intake valve is arranged on the intake pipe.

7. The targeted drilling mud annular film formation simulation device according to any one of claims 1 to 4, characterized in that: The liquid adding mechanism comprises a mud pool, a mud injection valve and a mud pipe; One end of the mud pipe is connected to the mud pool, and the other end passes through the first well cavity or the second well cavity and communicates with the well cavity of the simulated well body; The mud injection valve is arranged on the mud pipe.

8. The targeted drilling mud annular film formation simulation device according to any one of claims 1 to 4, characterized in that: The water filtering mechanism comprises a water filtering pipe and a water filtering measuring cylinder; One end of the water filter tube is connected to the cylinder wall at the bottom of the sealing sleeve and communicates with the inner cavity of the sealing sleeve, and the other end of the water filter tube is located directly above the water filter measuring cylinder.

9. The targeted drilling mud annular film formation simulation device according to any one of claims 1 to 4, characterized in that: It also includes a host computer and several seepage pressure sensors; The seepage pressure sensor is arranged on the inner wall of the annular filtration cavity, and there are a plurality of evenly distributed seepage pressure sensors in the same circumferential direction of the annular filtration cavity, and there are also a plurality of evenly distributed seepage pressure sensors in the axial direction of the annular filtration cavity; Each of the seepage pressure sensors is electrically connected to the host computer via a cable, and the cable passes through the sealing sleeve, the first well cavity or the second well cavity.

10. A method for forming a targeted drilling mud annular film, characterized in that: The targeted drilling mud annular film forming simulation device according to claim 9 is used, and the targeted drilling mud annular film forming method comprises the following steps: Step 101, after arranging pressure seepage sensors uniformly distributed circumferentially and axially on the inner wall of the annular fluid loss cavity, filling the inner wall of the annular fluid loss cavity with a simulated formation required for the test, so that the inner wall of the simulated formation is flush with the inner walls of the first well cavity and the second well cavity; Step 102, sealingly connecting the annular filtration cavity with the first well cavity and the second well cavity to form a simulated well body and connecting the cable between the pressure seepage sensor and the host computer; Step 103, after installing the sealing sleeve, the pressurizing mechanism, the liquid adding mechanism and the water filtering mechanism, the pitch angle of the simulated well body on the support is adjusted to the drilling angle required for the test simulation; Step 104, setting the output pressure of the pressurizing mechanism and the time interval for the upper computer to collect pressure data, injecting the mud required for the test prepared in advance into the wellbore of the simulated well body through the liquid adding mechanism, and stopping the injection after the entire wellbore is filled; Step 105, start the pressurizing mechanism and open the water filtering mechanism to start the film forming test, and start timing at the same time; Step 106, after the film forming test is completed, the pressurizing mechanism is closed and the excess gas is released, the sealing sleeve is removed and the annular filtration cavity with the simulated formation and the annular mud film is taken out; Step 107, after cutting the simulated formation and the annular mud film into two semi-cylindrical structure units along the opening line of the annular filtration cavity, the annular filtration cavity is opened, and two simulated formation units with mud films are taken out respectively, and the test data are recorded; Step 108, after changing the performance parameters of the simulated formation, perform steps 101 to 107 again to obtain different test schemes and record test data, and analyze the characteristics of the spatial annular mud film and its influencing factors; The analysis of the spatial annular mud film characteristics and influencing factors specifically includes the following steps: Step 201, cutting two simulated formation units with mud film obtained under the condition of a set drilling inclination angle into multiple mud film formation samples along the axial direction, and the size of the mud film formation samples is the same as the size of the filter structure on the mud film permeability test cavity; Step 202, after selecting a mud film formation sample and filling it on the inner wall of the filter structure of the mud film permeability test cavity, the mud film permeability test cavity is sealed and connected with the first well cavity and the second well cavity to form a simulated well body and connect the cable between the pressure seepage sensor and the host computer; Step 203, after installing the sealing sleeve, the pressurizing mechanism, the liquid adding mechanism and the water filtering mechanism, adjust the pitch angle of the simulated well body on the bracket to make the simulated well body horizontal; Step 204, setting the output pressure of the pressurizing mechanism and the time interval for the upper computer to collect pressure data, injecting water into the well cavity of the simulated well body through the liquid injection mechanism, and stopping the injection after the entire well cavity is filled; Step 205, start the pressurizing mechanism and open the water filtering mechanism to start the filtration test, and start the timing at the same time; Step 206, after the filtration test is completed, the pressurizing mechanism is closed and the excess gas is released, and then the mud film formation sample is taken out and its permeability is recorded; Step 207, select the next mud film formation sample and repeat steps 202 to 206 until all mud film formation samples have completed the permeability test, so as to analyze the permeability characteristics of mud films in different spatial regions.

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