Well drilling and completion simulation device in hydrate pressure maintaining drilling and production process

Abstract

The invention discloses a well drilling and completion simulation device in the hydrate pressure maintaining drilling and production process, and the device comprises a shaft screen pipe simulation part, a positive and negative circulation system part and a drill rod rotation simulation part, and the shaft screen pipe simulation part comprises a shaft and a screen pipe assembly (26); the positive and negative circulation system component is connected with a shaft through a positive and negative drainage liquid injection port (34) and used for adjusting different pressures to conduct mining simulation, the drill rod rotation simulation component is connected with a screen pipe assembly (26), and double motors are adopted for independent control, so that synchronous matching simulation of drilling and screen pipe lowering is achieved. The device is high in measurement precision, simple in structure, reliable in performance, convenient to move, small in size, easy to operate and high in practicability, and meets the requirement for intelligent development of hydrate pressure maintaining drilling and well completion engineering operation.

Description

Technical Field

[0001] The invention relates to the technical field of hydrate reservoir exploitation, and in particular to a drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and exploitation. Background Art

[0002] At present, in the exploration and development of fossil energy such as oil, natural gas, coalbed methane and shale gas, drilling and completion construction are the main technical means of development. As a new type of clean energy that can alleviate the problem of energy shortage, hydrates are very abundant in resources and have broad development prospects. However, since the mining technology cannot achieve long-term, efficient and economic development, the hydrate mining method is still in the key research stage. Therefore, it is urgent to carry out a large number of related experimental studies to study the hydrate mining mechanism and the scientific and technological research of efficient mining methods, so as to achieve the purpose of guiding on-site construction with the results of simulation experiments.

[0003] At present, hydrate reservoirs are mainly mined by depressurization, heating, injection, and replacement after drilling and completion. Therefore, the drilling and completion process is a necessary means for the exploitation of hydrate reservoirs. In the actual drilling and completion process, the bottom hole pressure often decreases, which leads to the automatic decomposition of hydrates in the reservoir as the pressure decreases. The sand particles produced enter the wellbore, causing the wellbore safety problem of sand production at the bottom of the well. The natural gas produced by the decomposition will also enter the atmosphere, causing various environmental risks. Even after the decomposition of hydrates, the original skeleton structure of the reservoir will collapse, changing the formation stress field, causing wellbore and reservoir collapse, mining equipment being buried and other production control risks. Therefore, in the process of simulating the depressurization of hydrate reservoir drilling and completion, it is necessary to realize the simultaneous lowering of screens while drilling, and integrate the on-site drilling process to keep the pressure in the wellbore sealed and stable, avoid the automatic decomposition of natural gas hydrates in the wellbore to cause production and safety problems, and realize the safe and efficient development of hydrate reservoirs. However, none of the currently known related simulation devices can realize the pressure-maintaining drilling and production simulation process of hydrate reservoirs. Therefore, there is an urgent need to develop a drilling and completion simulation device that can achieve pressure-maintaining sealing under laboratory conditions. The experimental device can simulate the drilling and completion process of a hydrate reservoir with complete pressure-maintaining sealing under laboratory conditions, thereby providing relevant theoretical and technical basis for the depressurization exploitation of natural gas hydrate reservoirs. Summary of the invention

[0004] The purpose of the present invention is to provide a drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production, so as to solve the technical problem that the experimental device in the prior art cannot simulate the pressure-maintaining and sealing drilling and completion process of hydrate reservoirs.

[0005] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: a drilling and completion simulation device for hydrate pressure-maintaining drilling and production provided by the present invention includes a system frame component, a wellbore screen simulation component, a kettle body installation component, a forward and reverse circulation system component and a drill pipe rotation simulation component, the system frame component includes a fixed plate, a guide sleeve, a guide rod, a system support frame and other components, which support and fix the device as a whole, the wellbore screen simulation component includes a wellbore and a screen assembly, the kettle body installation component connects the kettle body connecting column to the simulated kettle body end cover through a connecting column bolt, the forward and reverse circulation system component is connected to the wellbore through a positive and reverse liquid discharge port to adjust different pressures for production simulation, the drill pipe rotation simulation component is connected to the screen assembly, and adopts dual motor independent control to realize the synchronous coordination simulation of drilling and lowering the screen.

[0006] Furthermore, the system frame component includes a first guide rod, a first guide sleeve, a guide plate and a force-bearing support plate. The first guide rod and the guide plate are connected to form a fixed frame, which is fixed as a whole by the system support frame; the first guide rod and the force-bearing support plate are slidably connected by the first guide sleeve, and the first guide sleeve is fixed by an outer locking spring and the force-bearing support plate.

[0007] Furthermore, the system frame component also includes a second guide rod, a second guide sleeve and a locking nut. The second guide rod and the second guide sleeve cooperate to achieve linear sliding. After the second guide rod and the locking nut are locked, the guide fixing plate is fixed.

[0008] Furthermore, the wellbore screen simulation component includes a reducer reinforcement rib, a reducer assembly and a stepper motor. The reducer reinforcement rib is connected to the ball screw through a coupling, the ball screw and the guide fixing plate are locked, the pressure bearing system is axially supported, and dust prevention is achieved through the lower end cover of the bearing. The reducer assembly is connected to the ball screw through a coupling, and the ball screw is connected to the force support plate through the screw nut connecting pin. The linear motion of the ball screw is transmitted to the wellbore and the screen assembly for linear motion. The wellbore and the screen assembly are connected together through threads, driving the screen assembly to move up and down. At the same time, the sealing of the two is achieved through the O-ring seal, and a uniform filter element anti-sand assembly is opened on the side wall of the screen assembly.

[0009] Furthermore, the kettle body installation components include a kettle body connecting column, a simulated kettle body end cover, a connecting column bolt, and a locking nut. The drilling and completion simulation device is arranged on the kettle body connecting column. The kettle body connecting column is connected to the kettle body through the connecting column bolts and is fixed to the simulated kettle body end cover with a locking nut.

[0010] Furthermore, the forward and reverse circulation system components include a circulation pump, and the forward and reverse liquid injection ports are respectively connected to the inlet and outlet of the circulation pump, and are connected to form a complete circulating liquid forward and reverse circulation process through the circulation pump, the filter kettle, the stirring container, the back pressure valve and the one-way valve. By injecting clean water into the forward and reverse liquid injection ports, the water-sand mixture passes through the metal filter element in the filter kettle to filter out solid particles, and the stirring paddle in the stirring container stirs the water-sand mixture evenly. The water body follows the circulation pipeline to move to the subsequent pipeline to continue the forward and reverse circulation. As the simulated drilling proceeds, the sewage is discharged back inside the screen tube assembly.

[0011] Furthermore, the drill pipe rotation simulation component includes a servo motor, which is connected to the guide plate through a motor connection flange and locked by a motor locking screw, and the guide plate and the motor connection flange are connected and fixed by flange locking screws; the drill pipe rotation simulation component also includes a simulated drill pipe, the simulated drill pipe and the motor shaft are connected to each other through a motor coupling, and the two are fixed together through a coupling pin, and the torque of the motor is transmitted to the diamond drill bit through the simulated drill pipe, and the simulated drill pipe and the diamond drill bit are arranged inside the screen assembly. As the screen assembly moves downward, the simulated drill pipe and the diamond drill bit also achieve synchronous rotation.

[0012] Furthermore, the diameter of the kettle body connecting column is adjusted by adjusting the connecting column bolts, thereby adjusting the size of the screen assembly, the simulated drill pipe and the diamond drill bit to adapt to the combined drilling and completion simulation of drill columns of different diameters.

[0013] Furthermore, during the drilling and production process, the system pressure can be loaded to the formation pressure through the circulation pump in the forward and reverse circulation system components, thereby simulating the reservoir formation process at a low temperature where pressure is maintained.

[0014] The beneficial effects of the present invention are as follows: the present invention can simulate the pressure-maintaining drilling and completion process under the formation overburden pressure after the hydrate accumulation is more realistic; the drilling and production simulation technology is adopted to simulate the on-site drilling and production process in an integrated manner, and the screen pipe is lowered while drilling, which can effectively simulate the continuous process on site; the pressure-maintaining drilling process under formation conditions is realized; by designing a positive and negative discharge circulation system, the migration and circulation process of mud under the formation is effectively simulated; by independent control of dual motors, the synchronous coordination simulation of drilling and lowering of the screen pipe is realized; through the drilling and production simulation process, relevant basis can be effectively provided for the sand prevention treatment of mining. The present invention has high measurement accuracy, simple structure, reliable performance, small size, convenient movement, simple operation, strong practicality, and meets the intelligent development needs of hydrate pressure-maintaining drilling and completion engineering operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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.

[0016] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Partial zoom Figure 1 ; Figure 3 for Figure 1 Partial zoom Figure 2 ; Figure 4 for Figure 1 Partial zoom Figure 3 ; Figure 5 It is a schematic diagram of the structure of the components of the forward and reverse circulation system; In the figure, 1-locking nut, 2-reducer reinforcement rib, 3-reducer assembly, 4-coupling, 5-bearing end cover locking screw, 6-pressure bearing, 7-bearing upper end cover, 8-guide fixing plate, 9-screw nut connecting pin, 10-locking retaining spring, 11-first guide sleeve, 12-guide rod locking screw, 13-force support plate, 14-servo motor, 15-motor locking screw, 16-motor coupling, 17-coupling pin, 18-motor connecting flange, 19-flange locking screw, 20-first guide rod, 21-guide plate, 22-ball screw, 23-bearing lower end cover, 24-kettle body connecting cylinder, 25-connecting cylinder bolt, 26-screen assembly, 27-filter element anti-sand assembly, 28-simulated drill Rod, 29-diamond drill bit, 30-simulated kettle end cover, 31-locking nut, 32-second guide rod, 33-system support frame, 34-positive and negative liquid discharge and injection port, 35-second guide sleeve, 36-circulating liquid, 37-clean water, 38-first one-way valve, 39-second one-way valve, 40-positive and negative circulation pipeline, 41-circulating pump, 42-mixing container, 43-mixing paddle, 44-back pressure valve, 45-back pressure regulating pump, 46-filter kettle, 47-metal filter element, 48-water-sand mixture, 49-heating device, 50-medicine injection port, 51-kettle body, 52-first flow limiting valve, 53-second flow limiting valve, 54-first one-way flow limiting valve, 55-second one-way flow limiting valve, 56-third one-way flow limiting valve. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0018] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0019] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0020] See also Figures 1 to 5 A drilling and completion simulation device for hydrate pressure-maintaining drilling and production includes a system frame component, a wellbore screen simulation component, a kettle installation component, a forward and reverse circulation system component, and a drill pipe rotation simulation component.

[0021] The system frame components include a locking nut 1, a guide fixing plate 8, a first guide sleeve 11, a guide rod locking screw 12, a force-bearing support plate 13, a first guide rod 20, a guide plate 21, a second guide rod 32, a system support frame 33, and a second guide sleeve 35, wherein the first guide rod 20 and the guide plate 21 are connected to form a fixed frame, which is fixed as a whole by the system support frame 33 to ensure the concentricity of the system, the lower end of the first guide rod 20 is connected to the guide plate 21, the first guide rod 20 and the force-bearing support plate 13 are connected by threads and fixed by the guide rod locking screw 12, the first guide rod 20 and the force-bearing support plate 13 are slidably connected by the first guide sleeve 11, and the first guide sleeve 11 is fixed by the outer locking spring 10 and the force-bearing support plate 13. The first guide sleeve 11 and the first guide rod 20 are made of different materials to achieve relative sliding. Similarly, the second guide rod 32 and the second guide sleeve 35 cooperate to achieve linear sliding. The guide plate 21 achieves reciprocating motion under the joint action of the first guide rod 20, the second guide rod 32 and the guide sleeve to ensure the linear motion of the guide plate 21. After the second guide rod 32 and the locking nut 1 are locked, the guide fixing plate 8 is fixed to provide support force for the reciprocating motion of the system.

[0022] It should be noted that the guide fixing plate 8, the force supporting plate 13, the first guide rod 20, and the second guide rod 32 in the system frame components are all made of 9% carbon steel, are all pressure-resistant structures and can withstand high loads, and the guide sleeve is made of nickel steel. The first guide sleeve 11 and the first guide rod 20 are made of different materials to achieve relative sliding. Similarly, the second guide rod 32 and the second guide sleeve 35 cooperate to achieve linear sliding. The guide sleeve (including the first guide sleeve 11 and the second guide sleeve 35) and the guide rod (including the first guide rod 20 and the second guide rod 32) can achieve relative sliding in the process of simulating hydrate drilling and mining. The guide plate 21 realizes the reciprocating motion of the entire system under the joint action of the first guide rod 20, the second guide rod 32 and the guide sleeve, ensuring the linear motion of the guide plate 21.

[0023] The wellbore screen simulation component includes a reducer reinforcement rib 2, a reducer assembly 3, a coupling 4, a bearing end cover locking screw 5, a pressure bearing 6, a bearing upper end cover 7, a screw nut connecting pin 9, a ball screw 22, a bearing lower end cover 23, a screen assembly 26, and a filter element sand prevention assembly 27, wherein the reducer reinforcement rib 2 fixes the stepper motor and the reducer assembly 3 to provide rotational motion, the reducer reinforcement rib 2 is connected to the ball screw 22 through the coupling 4, the pressure bearing 6 and the bearing upper end cover 7 are compressed and sealed by the bearing end cover locking screw 5, the ball screw 22 and the guide fixing plate 8 are locked, the system axial support is provided by the pressure bearing 6, and dust prevention is achieved by the bearing lower end cover 23. The reducer assembly 3 is connected to the ball screw 22 through the coupling 4 to convert the rotational motion into linear motion. The ball screw 22 is connected to the force support plate 13 through the screw nut connecting pin 9, and the linear motion of the ball screw 22 is transmitted to the wellbore and the screen assembly 26 for linear motion. The wellbore and the screen assembly 26 are connected together by threads, driving the screen assembly 26 to move up and down, and the O-ring seal is used to achieve the sealing of the two. A filter element sand prevention assembly 27 composed of multiple metal wire mesh elements is evenly and symmetrically distributed in the screen assembly 26, which can prevent the formation gravel brought by the decomposition of hydrates from the outside of the screen assembly 26, effectively prevent the invasion of fine sand, and play a role in sand prevention.

[0024] In addition, a heating device 49 and a chemical injection port 50 are provided in the wellbore. The temperature in the wellbore can be increased by the heating device 49, and a chemical promoting hydrate degradation agent can be added through the chemical injection port 50 to catalyze the decomposition of hydrates in the wellbore. The decomposition of hydrates in the wellbore can be promoted by a superposition of heating, reducing pressure and injecting chemical agents.

[0025] The kettle installation components include a kettle connecting column 24, a connecting column bolt 25, a simulated kettle end cover 30, and a locking nut 31. The entire device is connected to the simulated kettle end cover 30 through the kettle connecting column 24. The kettle connecting column 24 is connected to the kettle through the connecting column bolt 25 and is fixed to the simulated kettle end cover 30 with a locking nut 31 to simulate the wellhead and completion structure. It should be pointed out that the sealing of the screen assembly 26 and the kettle connecting column 24 is achieved by an O-ring seal.

[0026] The forward and reverse circulation system components include forward and reverse liquid discharge and injection ports 34 reserved at the wellbore, circulating liquid 36, clean water 37, a first one-way valve 38, a second one-way valve 39, a forward and reverse circulation pipeline 40, a circulation pump 41, a stirring container 42, a back pressure valve 44, a filter kettle 46, a metal filter element 47, and a water-sand mixture 48. A forward and reverse liquid discharge and injection port 34 is reserved at the wellbore, and two liquid injection ports are respectively connected to the inlet and outlet of the circulation pump 41, connected to the first one-way valve 38 and the second one-way valve 39, and a square tee is arranged on the forward and reverse circulation pipeline 40, through the circulation pump 41 and The filter kettle 46, the stirring container 42 and the back pressure valve 44 are connected to form a complete forward and reverse circulation process of the circulating fluid 36. Clean water 37 is injected into the forward and reverse liquid injection ports 34 at the wellbore. During drilling, the stirring paddle 43 in the stirring container 42 can stir the water-sand mixture 48 evenly. When the water-sand mixture 48 passes through the filter kettle 46, the metal filter element 47 in the filter kettle 46 filters out the solid particles, and the water body circulates to the subsequent pipeline to continue the forward and reverse circulation. As the simulated drilling proceeds, sewage is discharged from the screen tube assembly 26 to simulate the circulation discharge of mud.

[0027] In addition, a plurality of throttle valves and one-way flow limiting valves are also provided on the forward and reverse circulation pipeline 40 to better control the experimental process. Specifically, a first flow limiting valve 52, a first one-way flow limiting valve 54, a second one-way flow limiting valve 55, a third one-way flow limiting valve 56 and a second flow limiting valve 53 are sequentially provided on the forward and reverse circulation pipeline 40. In addition, in order to facilitate the control of the experimental process, in some embodiments, corresponding valves can be added or reduced. The valves here include not only flow limiting valves or one-way flow limiting valves, but also control ball valves, etc. As long as it is convenient for the control device to conduct experiments, the present invention does not limit the valves provided on the forward and reverse circulation pipeline 40. The working process of the forward and reverse circulation system components is as follows: clean water 37 is injected into the forward and reverse liquid injection ports 34 at the wellbore, the water-sand mixture 48 passes through the metal filter element 47 in the filter kettle 46 to filter out solid particles, and the water-sand mixture 48 is evenly stirred by the stirring paddle 43 in the stirring container 42, and the water body follows the circulation pipeline to move to the subsequent pipeline to continue the forward and reverse circulation. As the simulated drilling proceeds, sewage is reversely discharged from the screen tube assembly 26 to simulate the circulation discharge of mud. The entire process can simulate the mud injection, discharge and circulation process in the drilling and production cycle.

[0028] The drill pipe rotation simulation component includes a servo motor 14, a motor locking screw 15, a motor coupling 16, a coupling pin 17, a motor connecting flange 18, a flange locking screw 19, a simulated drill pipe 28, and a diamond drill bit 29, wherein the drilling components such as the simulated drill pipe 28 and the diamond drill bit 29 are arranged inside the screen tube component 26, the servo motor 14 is connected to the guide plate 21 through the motor connecting flange 18, which is locked by the motor locking screw 15, and the guide plate 21 and the motor connecting flange 18 are connected and fixed by the flange locking screw 19, and the simulated The drill rod 28 and the motor shaft are connected to each other through the motor coupling 16, and the two are fixed together through the coupling pin 17 to achieve synchronous rotation. At the same time, the servo motor increases the torque through the reducer, and transmits the torque of the motor to the diamond drill bit 29 through the simulated drill rod 28. During the drilling process, the simulated kettle end cover 30 can realize the drilling process in which the simulated drill rod 28 also rotates synchronously with the downward movement of the screen assembly 26. The overall device is connected through the kettle connecting column 24 and the simulated kettle end cover 30 to simulate the completion process after drilling. In addition, the diameter of the kettle connecting column 24 can be adjusted by adjusting the connecting column bolt 25, and then the size of the screen assembly 26, the simulated drill rod 28 and the diamond drill bit 29 can be adjusted to adapt to the combined drilling and completion simulation of drill strings of different diameters.

[0029] It should be noted that, in the process of the wellbore and the screen pipe moving downward at the same time, circulating fluid of the formation pressure can be injected into the wellbore through the positive and negative injection ports 34, so that the formation pressure is maintained in the wellbore and the screen pipe, and pressure-maintained drilling under formation conditions is achieved; when adjusting the pressure, the back pressure of the regulating back pressure valve 44 can be accurately adjusted by the back pressure regulating pump 45, and different pressures can be adjusted to simulate pressure reduction production; in the drilling process, by pressurizing the system to the formation conditions, a positive and negative injection port 34 is left in the wellbore, and by connecting the peripheral circulation pump and the circulation system pipeline (the positive and negative circulation pipeline 40), the pressure of the positive and negative circulation pipeline 40 is loaded to the formation pressure through the circulation pump 41, so as to simulate the pressure-maintained low-temperature reservoir formation process.

[0030] The implementation process of the present invention is as follows: Drilling process: After checking that the equipment is fully connected, the experimental operator turns on the servo motor 14 and sets appropriate speed and drilling pressure values ​​to provide rotational motion. The reducer assembly 3 is connected to the ball screw 22 through the coupling 4 to convert the rotational motion into linear motion, which is transmitted to the wellbore and the screen assembly 26 for linear motion, thereby driving the screen assembly 26 to move up and down, realizing drilling and lowering the screen at the same time, and simulating the on-site drilling process in an integrated manner. During drilling, the experimental operator injects clean water 37 into the positive and negative injection ports 34 at the wellbore, so that when the water-sand mixture 48 passes through the filter kettle 46, the metal filter element 47 in the filter kettle 46 is used to filter out the solid particles in the water-sand mixture 48, and the water-sand mixture 48 is stirred evenly by the stirring paddle 43 in the stirring container 42, so that the evenly mixed water body is circulated to the subsequent pipeline to continue the positive and negative circulation. As the simulated drilling process proceeds, the circulating sewage is reversed and discharged from the screen assembly 26 to simulate the circulating discharge of the drilling fluid during drilling. It is worth noting that the water produced by the decomposition of hydrates in the wellbore will also enter the positive and negative circulation system and be recycled again.

[0031] Simulated completion process: When simulating the completion process after drilling, the experimental operator turns on the servo motor 14 and sets the appropriate speed value and drilling pressure value. The motor rotation drives the motor coupling 16 to drive the simulated drill pipe 28 to rotate, realizing synchronous rotation. At the same time, the servo motor torque is increased through the reducer assembly 3, and the torque of the motor is transmitted to the diamond drill bit 29 through the simulated drill pipe 28. In the simulated kettle end cover 30, the screen assembly 26 moves downward, and the simulated drill pipe 28 also maintains the synchronous rotation of the drilling process, driving the diamond drill bit 29 to break the simulated natural gas hydrate reservoir. At the same time, the wellbore and the screen assembly 26 are sealed by the O-ring seal, and the side wall of the screen assembly 26 is uniformly provided with a filter element anti-sand assembly 27 to prevent the intrusion of fine sand produced by the decomposition of natural gas hydrates, playing a role in sand prevention, simulating the completion process. The kettle body connecting column 24 is used to simulate the wellhead of on-site drilling in the formation. The device is connected to the kettle body through the connecting column bolts 25 and fixed to the simulated kettle body end cover 30 with a locking nut 31 to simulate the wellhead and completion structure.

[0032] Pressure reduction mining simulation process: This device mainly simulates pressure reduction mining, so the pressure adjustment in the circulation system pipeline connected to the wellbore is particularly important. Before starting, ensure that the throttle valve and one-way flow limiting valve in the circulation pipeline remain unobstructed. After the equipment is fully connected, the experimental operator uses the back pressure regulating pump 45 to accurately adjust the back pressure of the back pressure valve 44. Using a square tee arranged at the front end of the back pressure valve 44 in the forward and reverse circulation pipeline 40, the experimental operator can adjust the back pressure by adjusting the back pressure valve 44 to unload the excess pressure to the end of the pipeline, so as to maintain the pressure in the forward and reverse circulation pipeline stable. When the system back pressure is set at the formation pressure, the forward and reverse circulation system will be operated under the formation pressure condition, and the circulating fluid 36 will perform forward and reverse circulation. When mining is carried out, the circulating fluid 36 will stop circulating. At this time, the system maintains the formation pressure. The experimental operator gradually reduces the pressure by adjusting the back pressure regulating pump 45. After the pressure of the back pressure regulating pump 45 drops, the pressure of the back pressure valve 44 also drops. At this time, the pressure in the forward and reverse circulation pipeline 40 drops, causing the simulated hydrate to react in the direction of decomposition, releasing gas, water and solid gravel. The temperature in the wellbore can be increased by the heating device 49, and the hydrate degradation-promoting agent can be added through the agent injection port 50 to catalyze the decomposition of hydrates in the wellbore, thereby realizing the superposition of heating, pressure reduction and chemical injection to promote the accelerated decomposition of hydrates in the wellbore. The metal filter element 47 arranged on the side wall of the screen assembly 26 prevents the formation gravel brought by decomposition from being outside the screen assembly 26, ensuring that the pressure drops from the formation during the depressurization production process and the pressure drops toward the screen assembly 26. By controlling the pressure of the back pressure valve 44, the experimental operator can control the pressure in the wellbore and the screen assembly 26, thereby realizing the depressurization production simulation process of hydrates.

[0033] Parameter monitoring and collection: During the drilling process, completion process and drilling pressure adjustment process, the experimental operator can detect and collect the pressure in the system through the back pressure regulating pump 45, and use the sensor attached to the heating device 49 to monitor and collect real-time temperature data in the wellbore.

[0034] Based on the above embodiments, the present invention has at least the following technical effects: The present invention can simulate the pressure-maintaining drilling and completion process under the formation overburden pressure after the hydrate accumulation is more realistic; the drilling and production simulation technology is adopted to simulate the on-site drilling and production process in an integrated manner, and the screen pipe can be lowered while drilling, which can effectively simulate the continuous process on site; the simulated pressure-maintaining drilling process under formation conditions can be realized; by designing a positive and negative discharge circulation system, the migration, circulation and return flow process of the mud under the formation and the whole process of dynamic late pressure reduction production can be effectively simulated; through the independent control of dual motors, the synchronous coordination simulation of drilling and screen pipe lowering can be realized; through the positive and negative discharge circulation system, the back pressure valve system can be used to more effectively control the precise process of pressure reduction production under formation pressure; by designing an added heating device and a reagent injection port, in the simulated pressure reduction production process, the superimposed effects of heating, pressure reduction and chemical injection can be realized to promote the accelerated decomposition of hydrates in the wellbore; through the drilling and production simulation process, relevant basis can be effectively provided for sand prevention treatment in mining. The present invention has high measurement accuracy, simple structure, reliable performance, convenient movement, small size, simple operation, strong practicality and meets the needs of intelligent development of hydrate pressure-maintaining drilling and completion engineering operations.

[0035] For the aforementioned embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily required by the present application.

[0036] The above embodiments describe the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the changes and modifications made by those skilled in the art shall be within the scope of protection of the appended claims of the present invention without departing from the spirit and scope of the present invention.

Claims

1. A drilling and completion simulation device for hydrate pressure-maintaining drilling and production, characterized in that: The invention comprises a wellbore screen simulation component, a forward and reverse circulation system component and a drill pipe rotation simulation component. The wellbore screen simulation component comprises a wellbore and a screen assembly (26). The forward and reverse circulation system component is connected to the wellbore via a forward and reverse liquid discharge port (34) to adjust different pressures for mining simulation. The drill pipe rotation simulation component is connected to the screen assembly (26) and is independently controlled by dual motors to achieve synchronous coordination simulation of drilling and lowering the screen.

2. The drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production according to claim 1, characterized in that: The system also includes a system frame component, which includes a first guide rod (20), a guide plate (21) and a force-bearing support plate (13); the first guide rod (20) and the guide plate (21) are connected to form a fixed frame, which is fixed as a whole by a system support frame (33); the first guide rod (20) and the force-bearing support plate (13) are slidably connected by a first guide sleeve (11), and the first guide sleeve (11) is fixed to the force-bearing support plate (13) by an outer locking spring (10).

3. The drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production according to claim 2, characterized in that: The system frame component further comprises a second guide rod (32) and a second guide sleeve (35). The second guide rod (32) and the second guide sleeve (35) cooperate to achieve linear sliding. After the second guide rod (32) and the locking nut (1) are locked, the guide fixing plate (8) is fixed.

4. The drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production according to claim 3, characterized in that: The wellbore screen simulation component comprises a reducer reinforcement rib (2), the reducer reinforcement rib (2) is connected to a ball screw (22) via a coupling (4), the ball screw (22) and the guide fixing plate (8) are locked, axially supported by a pressure bearing (6) system, and dustproofing is achieved through a bearing lower end cover (23).

5. The drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production according to claim 4, characterized in that: The wellbore screen tube simulation component also includes a reducer assembly (3), the reducer assembly (3) is connected to a ball screw (22) via a coupling (4), the ball screw (22) is connected to a force-bearing support plate (13) via a screw nut connecting pin (9), the linear motion of the ball screw (22) is transmitted to the wellbore and the screen tube assembly (26) for linear motion, the wellbore and the screen tube assembly (26) are connected together via threads, driving the screen tube assembly (26) to move up and down, and at the same time, the two are sealed by an O-ring seal, and a uniform filter element anti-sand assembly (27) is opened on the side wall of the screen tube assembly (26).

6. The drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production according to claim 5, characterized in that: It also includes a kettle body installation component, the kettle body installation component includes a kettle body connecting cylinder (24), the drilling and completion simulation device is arranged on the kettle body connecting cylinder (24), the kettle body connecting cylinder (24) is connected to the kettle body by a connecting cylinder bolt (25), and is fixed to the simulation kettle body end cover (30) by a locking nut (31).

7. A drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production as claimed in claim 6, characterized in that: The forward and reverse circulation system components include a circulation pump (41), and the forward and reverse liquid discharge ports (34) are respectively connected to the inlet and outlet of the circulation pump (41). The circulation pump (41) and the filter kettle (46) as well as the stirring container (42) and the back pressure valve (44) are connected to form a complete circulating liquid (36) forward and reverse circulation pipeline (40). Clean water (37) is injected into the forward and reverse liquid discharge ports (34), and the stirring paddle (43) in the stirring container (42) stirs the water-sand mixture (48) uniformly. The water-sand mixture (48) passes through the metal filter element (47) in the filter kettle (46) to filter out solid particles, and the water body circulates to the subsequent pipeline to continue the forward and reverse circulation. As the simulated drilling proceeds, sewage is discharged back from the screen tube assembly (26).

8. The drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production according to claim 7, characterized in that: The drill rod rotation simulation component comprises a servo motor (14), the servo motor (14) is connected to a guide plate (21) via a motor connection flange (18), and is locked via a motor locking screw (15), and the guide plate (21) and the motor connection flange (18) are connected and fixed via a flange locking screw (19); the drill rod rotation simulation component also comprises a simulated drill rod (28), the simulated drill rod (28) and a motor shaft are connected to each other via a motor coupling (16), and the two are fixed together via a coupling pin (17), and the torque of the motor is transmitted to a diamond drill bit (29) via the simulated drill rod (28), and the simulated drill rod (28) and the diamond drill bit (29) are arranged inside the screen tube assembly (26).

9. A drilling and completion simulation device in the process of hydrate pressure-maintaining drilling and production as claimed in claim 8, characterized in that: The diameter of the kettle body connecting column (24) is adjusted by adjusting the connecting column bolts (25), thereby adjusting the sizes of the screen assembly (26), the simulated drill pipe (28) and the diamond drill bit (29) to adapt to the combined drilling and completion simulation of drill columns with different diameters.

10. A drilling and completion simulation device in a hydrate pressure-maintaining drilling and production process according to any one of claims 1 to 9, characterized in that: During the drilling and production process, the system pressure is loaded to the formation pressure through the forward and reverse circulation system components, thereby simulating the reservoir formation process at a low temperature with pressure maintenance.

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