A well wall strengthening simulation experimental device and experimental method

Abstract

The present invention discloses a wellbore strengthening simulation experimental device and experimental method, which relate to the field of drilling technology. The wellbore strengthening simulation experimental device comprises a slurry flow simulation module for containing experimental fluid; a leakage behavior statistics module for counting experimental fluid passing through a dynamic expansion fracture module; a pressure control module for simulating a pressure environment; a temperature control module for simulating a temperature environment; and a data acquisition module for collecting experimental data. The experimental fluid enters the leakage channel of the dynamic expansion fracture module from the outlet of the slurry flow simulation module and the inlet of the dynamic expansion fracture module, and then enters the leakage behavior statistics module from the outlet of the dynamic expansion fracture module and the inlet of the leakage behavior statistics module. The present invention can achieve effective control of pressure and temperature, thereby simulating extreme high temperature and high pressure as well as pressure fluctuations in deepwater formations, and can effectively simulate the pressure-bearing plugging failure law of the plugging layer and wellbore strengthening materials under complex stress and temperature environments.

Description

Technical Field

[0001] The present invention relates to the technical field of well drilling, in particular to a well wall strengthening simulation experimental device and an experimental method. Background Art

[0002] Deepwater areas are a crucial component of the trillion-yuan gas province in the western South China Sea. With the continuous advancement of deepwater oil and gas exploration and development, the area of ​​deepwater development is expanding, and the formation pressure systems are complex, posing a significant challenge to the safety and efficiency of drilling operations. Given the complex pressure systems of deepwater and ultra-deepwater formations in the South China Sea, there is an urgent need to establish a dynamic wellbore reinforcement simulation experimental device suitable for weak deepwater and ultra-deepwater formations. This will allow for the development of targeted, efficient wellbore reinforcement technologies to address lost circulation issues in these complex and weak deepwater and ultra-deepwater formations and significantly improve drilling safety and efficiency.

[0003] Due to the high temperature and complex formation pressure system of deepwater / ultra-deepwater formations, the plugging layer is not only exposed to a high temperature and pressure environment, but also has a significant impact on the sealing layer due to fluctuations in external pressure. The aperture of the fractures in the plugging layer also changes with changes in pressure. However, the current wellbore strengthening simulation experimental equipment cannot comprehensively simulate the above working conditions. Summary of the Invention

[0004] The purpose of the present invention is to provide a wellbore strengthening simulation experimental device and experimental method, which take into account the influence of high temperature of deepwater formation and wellbore pressure fluctuation on the plugging layer.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a wellbore strengthening simulation experimental device, comprising: a slurry flow simulation module, a dynamic crack expansion module, a leakage behavior statistics module, a pressure control module, a temperature control module and a data acquisition module;

[0007] The slurry flow simulation module is used to contain experimental fluid;

[0008] The dynamic expansion crack module includes a dynamic expansion crack kettle and a leakage module, wherein the leakage module is located in the dynamic expansion crack kettle and is provided with a leakage channel;

[0009] The leakage behavior statistics module is used to count the experimental fluid passing through the dynamic expansion fracture module;

[0010] The pressure control module is used to simulate the pressure environment, the temperature control module is used to simulate the temperature environment, and the data acquisition module is used to collect experimental data;

[0011] The outlet of the slurry flow simulation module is connected to the inlet of the dynamic expansion crack module, and the outlet of the dynamic expansion crack module is connected to the inlet of the leakage behavior statistics module. The experimental fluid enters the leakage channel of the dynamic expansion crack module from the outlet of the slurry flow simulation module and the inlet of the dynamic expansion crack module, and then enters the leakage behavior statistics module from the outlet of the dynamic expansion crack module and the inlet of the leakage behavior statistics module.

[0012] Preferably, the pressure control module includes a wellbore confining pressure pump, a wellbore pressure pump and a formation pressure pump. The wellbore confining pressure pump is connected to the dynamic expansion crack module. The wellbore confining pressure pump is used to apply pressure between the dynamic expansion crack kettle body of the dynamic expansion crack module and the leakage module. The wellbore pressure pump is connected to the dynamic expansion crack module through the slurry flow simulation module. The wellbore pressure pump is used to apply pressure to the inlet of the leakage channel. The formation pressure pump is connected to the dynamic expansion crack module through the leakage behavior statistics module. The formation pressure pump is used to apply pressure to the outlet of the leakage channel.

[0013] Preferably, the slurry flow simulation module includes a slurry kettle body, a stirring structure and a first pressurizing piston. The first pressurizing piston is located in the slurry kettle body and is slidingly connected to the slurry kettle body. The first pressurizing piston divides the interior of the slurry kettle body into a storage cavity and a first pressurizing cavity. The storage cavity is used to hold experimental fluid. The stirring structure is arranged on the kettle cover, and the kettle cover is connected to the slurry kettle body. The stirring structure extends into the storage cavity. The wellbore pressure pump is connected to the first pressurizing cavity, and the outlet of the slurry flow simulation module is connected to the storage cavity.

[0014] Preferably, a visualization window is provided on the dynamic expansion crack kettle body, and the visualization window is arranged parallel to the length direction of the leakage module;

[0015] The leakage module is a permeation type leakage module;

[0016] Alternatively, the leakage module is a crack-type leakage module, which includes a movable plate and a fixed plate, wherein the movable plate and the dynamically expanding crack kettle body are capable of relative movement, and the fixed plate and the dynamically expanding crack kettle body are relatively fixed, the movable plate is made of a transparent material, and the leakage channel is formed between the movable plate and the fixed plate;

[0017] Alternatively, the loss module is a composite loss module.

[0018] Preferably, the leakage behavior statistics module includes a balance, a fluid collection kettle body and a second pressurizing piston, the second pressurizing piston is located in the fluid collection kettle body and is slidably connected to the fluid collection kettle body, the second pressurizing piston divides the interior of the fluid collection kettle body into a collection cavity and a second pressurizing cavity, the collection cavity is connected to the inlet of the leakage behavior statistics module, and the second pressurizing cavity is respectively connected to the formation pressure pump and the balance.

[0019] Preferably, the temperature control module includes a first heating structure, a second heating structure and a third heating structure, the first heating structure is located in the slurry flow simulation module, the second heating structure is located in the dynamic expansion crack module, and the third heating structure is located in the leakage behavior statistics module.

[0020] Preferably, the data acquisition module includes a pressure sensor, a temperature sensor, a displacement sensor, a flow sensor and a control unit, and the control unit is electrically connected to the pressure sensor, the temperature sensor, the displacement sensor and the flow sensor respectively;

[0021] The dynamic expansion crack module is provided with a plurality of pressure sensors, a plurality of temperature sensors and a plurality of flow sensors, and the plurality of pressure sensors, the plurality of temperature sensors and the plurality of flow sensors are respectively arranged along the length direction of the leakage module.

[0022] The present invention also provides an experimental method using the well wall strengthening simulation experimental device, comprising the following steps:

[0023] Step 1: prepare the experimental fluid required for the experiment and add the experimental fluid into the slurry flow simulation module;

[0024] Step 2: Set the stirring speed of the stirring structure, and set the temperature of the slurry flow simulation module, the dynamic crack expansion module, and the leakage behavior statistics module;

[0025] Step 3: When the temperature rises to the set temperature, the wellbore pressure pump, the wellbore pressure pump, and the formation pressure pump are turned on, and the experimental fluid enters the dynamic expansion fracture module to form a plugging layer;

[0026] Step 4: Increase the pressure of the formation pressure pump and keep it constant, and continue to increase the pressure of the wellbore pressure pump until the pressure of the wellbore pressure pump is greater than the pressure of the wellbore confining pressure pump, and the size of the leakage channel becomes larger, until the plugging layer fails and the wellbore pressure is relieved to zero;

[0027] Step five: Increase the pressure of the wellbore confining pressure pump so that the pressure of the wellbore confining pressure pump is greater than the pressure of the wellbore pressure pump, and the size of the leakage channel is reduced.

[0028] Preferably, the process of locating the blocking position of the blocking layer includes:

[0029] measuring the pressure at the inlet of the dynamic propagation fracture module and the pressure at the outlet of the dynamic propagation fracture module;

[0030] Measure the pressure of the confining pressure cavity and the opening of the leakage channel;

[0031] The plugging position of the plugging layer under the dynamic balance condition of the leakage channel is calculated according to the force balance state formula of the leakage channel. The force balance state formula of the leakage channel is as follows:

[0032] P i ·w·L d +P t ·w·(LL d )=P C ·w·L

[0033] Where, P i is the pressure at the inlet of the dynamic expansion crack module, Pa; P t is the pressure at the outlet of the dynamic expansion crack module, Pa; P c is the pressure of the confining cavity, Pa; w is the opening of the leakage channel, m; L is the length of the leakage channel, m; L d is the dynamic blocking distance of the leakage channel, m;

[0034] Then we get:

[0035]

[0036] Preferably, when used to evaluate the temperature resistance of the experimental fluid or to select an experimental fluid of a specific operating temperature, in step 1, the experimental fluid is aged in the slurry flow simulation module;

[0037] When used to evaluate the temperature resistance of the plugging layer or to select a specific experimental fluid, in step three, the experimental fluid is aged in the dynamic expansion crack module.

[0038] Compared with the prior art, the present invention has achieved the following technical effects:

[0039] The wellbore reinforcement simulation experimental device of the present invention can simulate the fluid pressure exerted on different parts of a fracture, thereby simulating the opening and closing of fractures caused by different operating conditions under the action of formation pressure. This allows for wellbore reinforcement and plugging experiments with fixed and variable fracture apertures, as well as for evaluating the adaptability of experimental fluids (wellbore reinforcement materials) to the sealing layer environment. The present invention can effectively control pressure and temperature, thereby simulating the extreme high temperatures, high pressures, and pressure fluctuations in deepwater formations. It can also effectively simulate the pressure-bearing plugging failure patterns of the sealing layer and wellbore reinforcement materials under complex stress and temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. 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 these drawings without paying any creative work.

[0041] Figure 1 Schematic diagram of the well wall strengthening simulation experimental device of the present invention;

[0042] Figure 2 Schematic diagram of setting up insulation covers for the slurry flow simulation module, dynamic crack expansion module, and leakage behavior statistics module of the present invention;

[0043] Figure 3 Schematic diagram of a slurry flow simulation module of the present invention;

[0044] Figure 4 This is a schematic diagram of the dynamic expansion crack module of the present invention. Figure 1 ;

[0045] Figure 5 This is a schematic diagram of the dynamic expansion crack module of the present invention. Figure 2 ;

[0046] Figure 6 It is a schematic diagram of the fluid collection kettle of the present invention;

[0047] Figure 7 Schematic diagram of closing the leakage channel of the present invention (Pn<Pc, Pn is P i +P t );

[0048] Figure 8 Schematic diagram of the leakage channel opening of the present invention (Pn>Pc, Pn is P i +P t );

[0049] Figure 9 Schematic diagram of reclosing the leakage channel of the present invention (Pn<Pc, Pn is P i +P t );

[0050] In the figure: 1- slurry flow simulation module, 2- dynamic expansion crack module, 3- leakage behavior statistics module, 4- dynamic expansion crack kettle, 5- leakage module, 6- leakage channel, 7- wellbore confining pressure pump, 8- wellbore pressure pump, 9- formation pressure pump, 10- slurry kettle, 11- stirring structure, 12- first pressurizing piston, 13- storage chamber, 14- first pressurizing chamber, 15- movable plate, 16- fixed plate, 17- balance, 18- fluid collection kettle, 19- second pressurizing piston, 20- collection chamber, 21- second pressurizing chamber, 22- insulation sleeve, 23- confining pressure chamber, 24- displacement sensor, 25- pressure measuring port, 26- temperature measuring port, 27- buffer container. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0052] The purpose of the present invention is to provide a wellbore strengthening simulation experimental device and experimental method, which take into account the influence of high temperature of deepwater formation and wellbore pressure fluctuation on the plugging layer.

[0053] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Example 1

[0055] like Figures 1 to 9As shown, this embodiment provides a wellbore strengthening simulation experimental device, including: a slurry flow simulation module 1, a dynamic expansion crack module 2, a leakage behavior statistics module 3, a pressure control module, a temperature control module and a data acquisition module; the slurry flow simulation module 1 is used to hold the experimental fluid; the dynamic expansion crack module 2 includes a dynamic expansion crack kettle body 4 and a leakage module 5, the dynamic expansion crack kettle body 4 is a rectangular parallelepiped, the leakage module 5 is located in the dynamic expansion crack kettle body 4, the leakage module 5 is provided with a leakage channel 6, a confining pressure cavity 23 is formed between the dynamic expansion crack kettle body 4 and the leakage module 5, the confining pressure cavity 23 is also connected to the buffer container 27, and the leakage module 5 is used to simulate the opening of complex leaky layer cracks under the combined action of wellbore pressure, wellbore wall confining pressure and formation pressure. and closed; the leakage behavior statistics module 3 is used to count the experimental fluid passing through the dynamic expansion fracture module 2; the pressure control module is used to simulate the pressure environment, the temperature control module is used to simulate the temperature environment, and the data acquisition module is used to collect experimental data; the outlet of the slurry flow simulation module 1 is connected to the inlet of the dynamic expansion fracture module 2, and the outlet of the dynamic expansion fracture module 2 is connected to the inlet of the leakage behavior statistics module 3. The experimental fluid enters the leakage channel 6 of the dynamic expansion fracture module 2 from the outlet of the slurry flow simulation module 1 and the inlet of the dynamic expansion fracture module 2, and after interacting with the leakage channel 6, enters the leakage behavior statistics module 3 from the outlet of the dynamic expansion fracture module 2 and the inlet of the leakage behavior statistics module 3, and the experimental fluid forms a plugging layer in the leakage channel 6.

[0056] Specifically, in this embodiment, the pressure control module includes a well wall confining pressure pump 7, a wellbore pressure pump 8 and a formation pressure pump 9. The well wall confining pressure pump 7, the wellbore pressure pump 8 and the formation pressure pump 9 are all flow pumps with programmable functions, which can realize real-time control of displacement and pressure, simulate pressure fluctuations and the continuous action of complex fluid pressure, and output pressure of any periodic waveform (rectangular, sine, cosine, trapezoidal and a combination of multiple waveforms, etc.), and can realize pressure control of 0 to 60 MPa; the well wall confining pressure pump 7 is connected to the dynamic expansion crack module 2 through a high-pressure transmission pipeline, and a high-pressure valve is provided at the connection part. The outer surface of the leakage module 5 is sealed to isolate the pressure and fluid transmission of the confining pressure cavity 23 and the leakage channel 6. The confining pressure cavity 23 is filled with liquid, such as water or hydraulic oil. The well wall confining pressure pump 7 applies pressure to the outside of the leakage module 5 through the liquid in the confining pressure cavity 23. Different fluid pressures (wellbore confining pressure) and pressure fluctuations; the wellbore pressure pump 8 is connected to the dynamic expansion fracture module 2 through the slurry flow simulation module 1, and the pressure of the wellbore pressure pump 8 is transmitted to the leakage channel 6 of the dynamic expansion fracture module 2 through the slurry flow simulation module 1. The wellbore pressure pump 8 is used to apply different fluid pressures and pressure fluctuations to the inlet of the leakage channel 6 (that is, the inlet of the dynamic expansion fracture module 2). The wellbore pressure pump 8 can simulate the speed of different fluids injected into the leakage channel 6 and realize the change of injection pressure at the same time; the formation pressure pump 9 is connected to the dynamic expansion fracture module 2 through the leakage behavior statistics module 3, and the pressure of the formation pressure pump 9 is transmitted to the leakage channel 6 of the dynamic expansion fracture module 2 through the leakage behavior statistics module 3. The formation pressure pump 9 is used to apply different fluid pressures and pressure fluctuations to the outlet of the leakage channel 6 (that is, the outlet of the dynamic expansion fracture module 2).

[0057] In this embodiment, the slurry flow simulation module 1 includes a slurry kettle body 10, a stirring structure 11 and a first pressurizing piston 12. The first pressurizing piston 12 is located in the slurry kettle body 10 and is slidably connected to the slurry kettle body 10. The first pressurizing piston 12 divides the interior of the slurry kettle body 10 into a storage cavity 13 and a first pressurizing cavity 14. The storage cavity 13 is used to hold the experimental fluid. The stirring structure 11 is arranged on the kettle cover, and the kettle cover is connected to the slurry kettle body 10. The stirring structure 11 can be magnetic stirring or mechanical stirring. The stirring of the stirring structure 11 The mixing rod is extended into the storage chamber 13. When the stirring structure 11 is turned on, it can simulate the effect of the drill rod in the actual wellbore on the wellbore working fluid, and apply different shear forces to the experimental fluid in the slurry flow simulation module 1, so that the experimental fluid is evenly dispersed and in a flowing state; the wellbore pressure pump 8 is connected to the first pressurized chamber 14, the outlet of the slurry flow simulation module 1 is connected to the storage chamber 13, and the outlet of the slurry flow simulation module 1 is connected to the inlet of the dynamic expansion crack module 2 through a high-pressure transmission pipeline, and a high-pressure valve is provided at the connection part.

[0058] In this embodiment, two visualization windows are provided on the dynamic expansion crack kettle body 4, one visualization window is located at the top of the dynamic expansion crack kettle body 4, and the other visualization window is located on the side of the dynamic expansion crack kettle body 4. The visualization window is made of transparent sapphire material that is resistant to high temperature and high pressure. The visualization window is set parallel to the length direction of the leakage module 5, and visual observation of the blocking status is achieved through the visualization window.

[0059] In this embodiment, the leakage module 5 may be a permeation leakage module, a fracture leakage module or a composite leakage module, wherein the permeation leakage module and the composite leakage module are both prior arts.

[0060] When the leakage module 5 is a fracture-type leakage module, the leakage module 5 includes a movable plate 15 and a fixed plate 16. The movable plate 15 and the dynamic expansion fracture kettle body 4 can slide relative to each other, and a guide rod for guiding the movable plate 15 is provided in the dynamic expansion fracture kettle body 4. The limit switch ensures that it can move within a certain distance. The movable plate 15 is detachable, and the fixed plate 16 is relatively fixed to the dynamic expansion fracture kettle body 4. The movable plate 15 uses a transparent material to achieve visual observation, such as etched glass or sapphire, or the movable plate 15 uses rock to simulate the lithology of the formation, such as a natural rock plate or an artificially pressed rock plate. A leakage channel 6 is formed between the movable plate 15 and the fixed plate 16. The wellbore confining pressure pump 7 is used to apply different fluid pressures and pressure fluctuations to the upper surface of the movable plate 15, and the wellbore pressure pump 8 is used to apply different fluid pressures and pressure fluctuations to the lower surface of the movable plate 15. The different pressures on the upper and lower surfaces of movable plate 15 cause the entire plate 15 to translate, simulating the opening and closing of a crack under the combined effects of wellbore pressure, confining pressure from the wellbore wall, and formation pressure. When the pressure on the upper surface of movable plate 15 is greater than the pressure on the lower surface, the crack aperture decreases and closes. When the pressure on the lower surface of movable plate 15 is greater than the pressure on the upper surface, the crack aperture increases and opens.

[0061] When the leakage module 5 is a permeable leakage module, it replaces the leakage channel 6 of the fracture leakage module with a permeable medium. The leakage module 5 uses a removable, manually pressed rock plate. By replacing the rock plate, the simulation of formations with different porosities and permeabilities can be achieved. By using a specifically designed rock plate preparation mold, a replaceable permeable leakage module can be prepared. The size of the prepared permeable leakage module can match the dynamic expansion fracture kettle 4, and the dynamic expansion fracture kettle 4 can also fix the permeable leakage module.

[0062] When the leakage module 5 is a composite leakage module, the composite leakage module is designed as a leakage module 5 in which multiple cracks with different openings coexist as needed, that is, the composite leakage module needs to simulate the coexistence of multiple cracks at the same time through replaceable crack plates to achieve composite crack simulation of cracks with different openings.

[0063] When the leakage module 5 is a permeability-type leakage module or a composite leakage module, the wellbore pressure pump 7 is used to apply different fluid pressures and pressure fluctuations to the upper surface of the leakage module 5, and the wellbore pressure pump 8 is used to apply different fluid pressures and pressure fluctuations to the leakage channel 6.

[0064] In this embodiment, the leakage behavior statistics module 3 includes a balance 17, a fluid collection kettle body 18 and a second pressurizing piston 19. The second pressurizing piston 19 is located in the fluid collection kettle body 18 and is slidably connected to the fluid collection kettle body 18. The second pressurizing piston 19 divides the interior of the fluid collection kettle body 18 into a collection cavity 20 and a second pressurizing cavity 21. The collection cavity 20 is provided with an inlet of the leakage behavior statistics module 3. The inlet of the leakage behavior statistics module 3 is connected to the outlet of the dynamic expansion crack module 2 through a high-pressure transmission pipeline. A high-pressure valve is provided at the connection part. Water is contained in the second pressurizing cavity 21. 1 is provided with an outlet for the leakage statistics module 3, at which a flow sensor is installed. The outlet of the leakage statistics module 3 is connected to the graduated cylinder on the balance 17. The experimental fluid enters the collection chamber 20. The second pressurizing piston 19 moves, causing the water in the second pressurizing chamber 21 to enter the graduated cylinder. The mass of the experimental fluid is indirectly measured by measuring the mass of the water. The flow sensor and the high-precision balance 17 can collect and record the mass and volume of the fluid discharged from the outlet of the leakage statistics module 3 in real time. The second pressurizing chamber 21 is connected to the formation pressure pump 9, and a high-pressure valve is installed at the connection point. The leakage statistics module 3 not only enables real-time measurement of leakage volume and leakage rate, but also enables the collection and reuse of experimental fluid. A buffer container 27 is installed in the pipeline between the fluid collection kettle 18 and the formation pressure pump 9 to act as a buffer when the experimental fluid passes through the plugging layer.

[0065] In this embodiment, the temperature control module includes a first heating structure, a second heating structure, and a third heating structure. The first heating structure is located in the slurry flow simulation module 1 and is used to heat the experimental fluid. The second heating structure is located in the dynamic expansion fracture module 2 and is used to heat the experimental fluid. The third heating structure is located in the leakage behavior statistics module 3 and is used to heat the experimental fluid. The slurry flow simulation module 1, the dynamic expansion fracture module 2, and the leakage behavior statistics module 3 are externally provided with an insulation sleeve 22. The first, second, and third heating structures are all heating plates that can simulate and control the leaking layer temperature from room temperature to 260°C. The first, second, and third heating structures can be controlled independently. The temperature control module can be used to simulate the failure process of the experimental fluid (wellbore reinforcement material) under extremely high temperature and complex pressure environments. It can also simulate the temperature resistance of different experimental fluid (wellbore reinforcement material) formulations and the pressure bearing capacity of different formulations at different temperatures.

[0066] In this embodiment, the data acquisition module includes a pressure sensor, a temperature sensor, a displacement sensor 24, a flow sensor, a touch panel and a control unit. The control unit is electrically connected to the pressure sensor, the temperature sensor, the displacement sensor 24, the flow sensor and the balance 17, respectively, so as to realize real-time monitoring of the pressure, temperature, displacement and flow in the simulation device; a pressure sensor is respectively provided in the slurry flow simulation module 1, the dynamic expansion crack module 2, the leakage behavior statistics module 3, the wellbore confining pressure pump 7, the wellbore pressure pump 8 and the formation pressure pump 9; a pressure sensor is respectively provided in the slurry flow simulation module 1, the dynamic expansion crack module 2, the leakage behavior statistics module 3, the first heating structure, A temperature sensor is respectively provided in the second heating structure and the third heating structure; two displacement sensors 24 are provided in the dynamic expansion crack module 2, one displacement sensor 24 is used to monitor the opening of the leakage channel 6, and the other displacement sensor 24 is used to monitor the displacement of the movable plate 15; a flow sensor is respectively provided at the inlet of the slurry flow simulation module 1, the outlet of the slurry flow simulation module 1, the inlet of the dynamic expansion crack module 2, the dynamic expansion crack module 2, the outlet of the dynamic expansion crack module 2, the inlet of the leakage behavior statistics module 3, the outlet of the leakage behavior statistics module 3, the outlet of the wellbore confining pressure pump 7, the outlet of the wellbore pressure pump 8 and the outlet of the formation pressure pump 9.

[0067] In this embodiment, the dynamic expansion crack module 2 is provided with a number of pressure sensors, a number of temperature sensors and a number of flow sensors, and the pressure sensors, the temperature sensors and the flow sensors are respectively arranged along the length direction of the leakage module 5, the pressure sensor is arranged in the corresponding pressure measuring port 25, the temperature sensor is arranged in the corresponding temperature measuring port 26, and the displacement sensor 24 is arranged in the corresponding displacement port. The pressure sensor, the temperature sensor and the flow sensor in the dynamic expansion crack module 2 are preferably provided with five, which can realize the pressure, temperature and flow monitoring at different positions. The length of the leakage module 5 is 100 cm, and the pressure sensors, the temperature sensors and the flow sensors are arranged at intervals of 5 cm along the length direction of the leakage channel 6 (i.e., the flow direction of the fluid), to realize the pressure distribution, flow attenuation and temperature attenuation test along the flow direction. Based on the pressure and flow at different parts of the tested plugging layer, the structural density of the different parts of the plugging layer is determined. Based on the change amplitude of the pressure and flow at different parts of the tested plugging layer, the degree of particle crushing at different parts of the plugging layer is determined.

[0068] In this embodiment, the temperature, flow, pressure, displacement and mass information of each part of the device are collected in real time through the data acquisition module. The collected data information is automatically transmitted to the computer and processed through the acquisition / control software, and is intuitively output in the form of real-time curves, raw data tables or animation demonstrations. The real-time collected data can be displayed on the touch panel or on the display of the computer equipped with the data acquisition / control software. The data that can be displayed in real time include the slurry flow simulation module 1, the inlet of the leakage channel 6, the outlet of the leakage channel 6, different positions inside the leakage channel 6, the confining pressure cavity 23, the leakage behavior statistical model, etc. The system also measures the pressure in block 3, the actual output pressures of the wellbore confining pressure pump 7, the wellbore pressure pump 8, and the formation pressure pump 9, the temperatures within the dynamic fracture expansion module 2, the slurry flow simulation module 1, and the leakage behavior statistics module 3, the opening of the leakage channel 6 and the displacement of the movable plate 15, the flow rates at the inlet and outlet of the slurry flow simulation module 1, the inlet and outlet of the dynamic fracture expansion module 2, the inlet and outlet of the leakage behavior statistics module 3, the actual displacements of the wellbore confining pressure pump 7, the wellbore pressure pump 8, and the formation pressure pump 9, and the quality of the leakage test fluid. Furthermore, the wellbore confining pressure pump 7, the wellbore pressure pump 8, the formation pressure pump 9, the first heating structure, the second heating structure, and the third heating structure can be controlled by software to adjust various experimental parameters in real time, resulting in simple operation and a high degree of automation.

[0069] In this embodiment, pressure and fluid sealing are achieved through O-rings at the connections of each structure.

[0070] The wellbore strengthening simulation experimental device of this embodiment can simulate the extreme high temperature of 260°C in deepwater formations through the temperature control module, and can simulate the fluid pressure on different parts of the cracks through the pressure control module. It can simulate the fluctuation of pressure and the continuous effect of complex fluid pressure, thereby simulating the opening and closing of complex leaky layer cracks under various working conditions. Combined with the visualization window and the data acquisition module, the pressure bearing capacity and failure process of the plugging layer under the effects of extreme high temperature and complex fluid pressure are evaluated, and the process of the experimental fluid (wellbore strengthening material) forming the plugging layer and the influence of different plugging layer depths, thicknesses, and structures on the pressure bearing capacity are analyzed. Based on this device, the failure process simulation of the experimental fluid (wellbore strengthening material) under extreme high temperature and complex pressure environments can be further realized. By setting different temperature and pressure environments, the experimental fluid (wellbore strengthening material) for different working conditions can be optimized and the formula can be optimized, and the adaptability of the experimental fluid (wellbore strengthening material) to the environment can be evaluated. The simulated experimental conditions of this device are closer to the actual deepwater deep drilling working conditions, which improves the guiding significance of the experimental results for on-site construction operations.

[0071] The present invention aims to improve the device structure, and the control process is the existing technology.

[0072] Example 2

[0073] This embodiment provides an experimental method using the wellbore strengthening simulation experimental device of embodiment 1, comprising the following steps:

[0074] Step 1: When using the wellbore strengthening simulation experimental device, first select the material of the movable plate 15 of the dynamic expansion fracture module 2 based on the research purpose, leakage type, and formation type. If full visualization is to be achieved, the material of the movable plate 15 can be a transparent material, such as etched glass or sapphire. Alternatively, natural rock plates or artificially pressed rock plate samples of specific lithology can be used to simulate the lithology of the actual formation and visualize the sealing layer formation process through a visualization window. Natural rock plates or artificially pressed rock plates can also be processed through mechanical processing to obtain permeable leakage modules or composite leakage modules to simulate permeable or fractured leakage layers.

[0075] Prepare the experimental fluid required for the experiment, add the experimental fluid to the slurry flow simulation module 1, connect the various structures of the wellbore strengthening simulation experimental device, turn on the power, and check through the data acquisition module whether the various pressure sensors, temperature sensors, flow sensors, displacement sensors 24, wellbore confining pressure pumps 7, wellbore pressure pumps 8, and formation pressure pumps 9 are connected to the acquisition / control software. After checking that they are correct, reset the various parameters and close all high-pressure valves; then set the temperature, pressure, and their change rules required for the experiment;

[0076] Step 2: Set the stirring speed of the stirring structure 11 to 1500 rpm, set the temperature of the slurry flow simulation module 1, the dynamic expansion crack module 2, and the leakage behavior statistics module 3 to 260°C, and perform a heating process;

[0077] Step 3: When the temperature rises to the set temperature, open the high-pressure valve between the wellbore confining pressure pump 7 and the confining pressure cavity 23, set the wellbore confining pressure to 10 MPa, start the wellbore confining pressure pump 7, open the high-pressure valve between the slurry flow simulation module 1 and the dynamic expansion fracture module 2, open the valve between the dynamic expansion fracture module 2 and the leakage behavior statistics module 3, set the wellbore pressure to 6 MPa, set the formation pressure to 4 MPa, start the wellbore pressure pump 8 and the formation pressure pump 9, and the experimental fluid enters the dynamic expansion fracture module 2 to form a plugging layer. Observe the movement of the experimental fluid in the leakage channel 6 through the visualization window, and observe the structural formation and stability of the plugging layer.

[0078] Step 4: The formation pressure is linearly increased to 5 MPa within 10 minutes and then kept constant. The wellbore pressure is increased so that the pressure of the wellbore pressure pump 8 is greater than the pressure of the wellbore confining pressure pump 7. The size of the leakage channel 6 increases and the crack gradually opens. The wellbore pressure is increased until the plugging layer fails and the wellbore pressure drops to zero. Experimental data is collected in real time and the structural changes of the plugging layer are observed.

[0079] Step 5: Set the wellbore confining pressure to increase linearly to 20 MPa within 10 minutes, so that the pressure of the wellbore confining pressure pump 7 is greater than the pressure of the wellbore pressure pump 8, the size of the leakage channel 6 is reduced, and the cracks are gradually closed. Collect experimental data in real time and observe the changes in the plugging layer structure.

[0080] In this embodiment, when the purpose of the experiment is to evaluate the temperature resistance of the experimental fluid or to select an experimental fluid for a specific operating temperature, in step 1, the experimental fluid is aged in the slurry flow simulation module 1 for 12 to 24 hours, and then injected into the dynamic expansion fracture module 2 by pressure drive. The failure of the experimental fluid is determined based on the pressure bearing capacity of the plugging layer.

[0081] When the purpose of the experiment is to evaluate the temperature resistance of the plugging layer or to select a specific experimental fluid, in step three, the experimental fluid is injected into the dynamic expansion crack module 2 under pressure to form a plugging layer. After the experimental fluid is aged in the dynamic expansion crack module 2 for 12 to 24 hours, the pressure bearing capacity of the plugging layer is tested, and the dynamic stability of the plugging layer structure is observed through a visualization window.

[0082] In this embodiment, the process of locating the blocking position of the blocking layer includes:

[0083] measuring the pressure at the inlet of the dynamic expansion crack module 2 and the pressure at the outlet of the dynamic expansion crack module 2;

[0084] Measure the pressure between the confining pressure cavity 23 and the opening of the leakage channel 6;

[0085] The plugging position of the plugging layer under the dynamic equilibrium condition of the leakage channel 6 is calculated according to the force balance state formula of the leakage channel 6. The force balance state formula of the leakage channel 6 is as follows:

[0086] P i ·w·L d +P t ·w·(LL d )=P C ·w·L

[0087] Where, P i is the pressure at the inlet of the dynamic expansion crack module 2, Pa; P t is the pressure at the outlet of the dynamic expansion crack module 2, Pa; P c is the pressure of the confining pressure cavity 23, Pa; w is the opening of the leakage channel 6, m; L is the length of the leakage channel 6, m; L d is the dynamic blocking distance of leakage channel 6, m;

[0088] Then we get:

[0089]

[0090] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. An experimental method using a wellbore strengthening simulation experimental device, characterized by: The wellbore strengthening simulation experimental device includes: a slurry flow simulation module, a dynamic crack expansion module, a leakage behavior statistics module, a pressure control module, a temperature control module and a data acquisition module; The slurry flow simulation module is used to contain experimental fluid; The dynamic expansion crack module includes a dynamic expansion crack kettle and a leakage module, wherein the leakage module is located in the dynamic expansion crack kettle and is provided with a leakage channel; The leakage behavior statistics module is used to count the experimental fluid passing through the dynamic expansion fracture module; The pressure control module is used to simulate the pressure environment, the temperature control module is used to simulate the temperature environment, and the data acquisition module is used to collect experimental data; The outlet of the slurry flow simulation module is communicated with the inlet of the dynamic expansion fracture module, and the outlet of the dynamic expansion fracture module is communicated with the inlet of the leakage behavior statistics module. The experimental fluid enters the leakage channel of the dynamic expansion fracture module through the outlet of the slurry flow simulation module and the inlet of the dynamic expansion fracture module, and then enters the leakage behavior statistics module through the outlet of the dynamic expansion fracture module and the inlet of the leakage behavior statistics module. The experimental method includes the following steps: Step 1: prepare the experimental fluid required for the experiment and add the experimental fluid into the slurry flow simulation module; Step 2: Set the stirring speed of the stirring structure, and set the temperature of the slurry flow simulation module, the dynamic crack expansion module, and the leakage behavior statistics module; Step 3: When the temperature rises to the set temperature, the wellbore pressure pump, the wellbore pressure pump, and the formation pressure pump are turned on, and the experimental fluid enters the dynamic expansion fracture module to form a plugging layer; Step 4: Increase the pressure of the formation pressure pump and keep it constant, and continue to increase the pressure of the wellbore pressure pump until the pressure of the wellbore pressure pump is greater than the pressure of the wellbore confining pressure pump, and the size of the leakage channel becomes larger, until the plugging layer fails and the wellbore pressure is relieved to zero; Step 5: Increase the pressure of the wellbore confining pressure pump so that the pressure of the wellbore confining pressure pump is greater than the pressure of the wellbore pressure pump, and the size of the leakage channel is reduced; The process of locating the plugging position of the plugging layer includes: measuring the pressure at the inlet of the dynamic propagation fracture module and the pressure at the outlet of the dynamic propagation fracture module; Measure the pressure of the confining pressure cavity and the opening of the leakage channel; The plugging position of the plugging layer under the dynamic balance condition of the leakage channel is calculated according to the force balance state formula of the leakage channel. The force balance state formula of the leakage channel is as follows: P i -w-L d +P t ·w-(L-L d )=P c -w-L Where, P i is the pressure at the inlet of the dynamic expansion crack module, Pa; P t is the pressure at the outlet of the dynamic expansion crack module, Pa; P c is the pressure of the confining cavity, Pa; w is the opening of the leakage channel, m; L is the length of the leakage channel, m; L d is the dynamic blocking distance of the leakage channel, m; Then we get:

2. The experimental method according to claim 1, characterized in that: The pressure control module includes a wellbore confining pressure pump, a wellbore pressure pump and a formation pressure pump. The wellbore confining pressure pump is connected to the dynamic expansion crack module. The wellbore confining pressure pump is used to apply pressure between the dynamic expansion crack kettle body of the dynamic expansion crack module and the leakage module. The wellbore pressure pump is connected to the dynamic expansion crack module through the slurry flow simulation module. The wellbore pressure pump is used to apply pressure to the inlet of the leakage channel. The formation pressure pump is connected to the dynamic expansion crack module through the leakage behavior statistics module. The formation pressure pump is used to apply pressure to the outlet of the leakage channel.

3. The experimental method according to claim 2, characterized in that: The slurry flow simulation module includes a slurry kettle body, a stirring structure and a first pressurizing piston. The first pressurizing piston is located in the slurry kettle body and is slidingly connected to the slurry kettle body. The first pressurizing piston divides the interior of the slurry kettle body into a storage cavity and a first pressurizing cavity. The storage cavity is used to hold experimental fluid. The stirring structure is arranged on the kettle cover, and the kettle cover is connected to the slurry kettle body. The stirring structure extends into the storage cavity. The wellbore pressure pump is connected to the first pressurizing cavity. The outlet of the slurry flow simulation module is connected to the storage cavity.

4. The experimental method according to claim 1, characterized in that: A visualization window is provided on the dynamic expansion crack kettle body, and the visualization window is arranged parallel to the length direction of the leakage module; The leakage module is a permeation type leakage module; Alternatively, the leakage module is a crack-type leakage module, which includes a movable plate and a fixed plate, wherein the movable plate and the dynamically expanding crack kettle body are capable of relative movement, and the fixed plate and the dynamically expanding crack kettle body are relatively fixed, the movable plate is made of a transparent material, and the leakage channel is formed between the movable plate and the fixed plate; Alternatively, the loss module is a composite loss module.

5. The experimental method according to claim 2, characterized in that: The leakage behavior statistics module includes a balance, a fluid collection kettle body and a second pressurizing piston. The second pressurizing piston is located in the fluid collection kettle body and is slidably connected to the fluid collection kettle body. The second pressurizing piston divides the interior of the fluid collection kettle body into a collection cavity and a second pressurizing cavity. The collection cavity is connected to the inlet of the leakage behavior statistics module, and the second pressurizing cavity is respectively connected to the formation pressure pump and the balance.

6. The experimental method according to claim 1, characterized in that: The temperature control module includes a first heating structure, a second heating structure and a third heating structure. The first heating structure is located in the slurry flow simulation module, the second heating structure is located in the dynamic expansion crack module, and the third heating structure is located in the leakage behavior statistics module.

7. The experimental method according to claim 1, characterized in that: The data acquisition module includes a pressure sensor, a temperature sensor, a displacement sensor, a flow sensor and a control unit, and the control unit is electrically connected to the pressure sensor, the temperature sensor, the displacement sensor and the flow sensor respectively; The dynamic expansion crack module is provided with a plurality of pressure sensors, a plurality of temperature sensors and a plurality of flow sensors, and the plurality of pressure sensors, the plurality of temperature sensors and the plurality of flow sensors are respectively arranged along the length direction of the leakage module.

8. The experimental method according to claim 1, characterized in that: When used to evaluate the temperature resistance of the experimental fluid or to select an experimental fluid for a specific operating temperature, in step 1, the experimental fluid is aged in the slurry flow simulation module; When used to evaluate the temperature resistance of the plugging layer or to select a specific experimental fluid, in step three, the experimental fluid is aged in the dynamic expansion crack module.

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