Experimental device and method for simulating cuttings migration during gas production in gas drilling formation

Abstract

The present application provides a kind of experimental device and method for simulating cuttings migration when formation gas production in gas drilling, gas circulation system, for simulating gas supply problem of drilling;Cuttings supply and recovery system, for simulating cuttings production when gas drilling, and filtering and recycling the discharged cuttings;Drill pipe rotation and eccentric system: including transparent wellbore, the front and rear ends of transparent wellbore are connected with cuttings supply and recovery system;Drill pipe is set in transparent wellbore by eccentric adjusting device;Formation gas production system: for simulating the gas production scene when actual wellbore encounters gas layer;Wellbore lifting system: for adjusting the inclination angle of transparent wellbore;Data measurement and processing system: multiple monitors and control equipment are provided, which are connected with computer, constitute data control and acquisition system, realize intelligent control.This application can simulate the cuttings migration law when formation gas production in gas horizontal drilling, and provide reliable basis for cuttings migration law problem when formation gas production.

Description

Experimental apparatus and methods for simulating cuttings transport during gas drilling formation gas production. Technical Field

[0001] This invention provides an experimental apparatus and method for simulating cuttings transport during gas drilling formation production, belonging to the field of gas drilling technology. Background Technology

[0002] Gas drilling is a drilling technology that uses gas instead of drilling fluid as the circulating medium. It is particularly suitable for formations with hard rock, strong wellbore stability, minimal formation fluid intrusion, low to medium pore pressure, water-scarce and arid regions, and formations sensitive to water-based or oil-based drilling fluids. Gas drilling offers unparalleled advantages over conventional drilling fluids due to its high mechanical drilling speed, effective prevention of water-sensitive shale collapse, and elimination of lost circulation. Gas drilling technology has demonstrated unique advantages and immense vitality, and is considered one of the fastest-growing specialized technologies in the drilling industry. Because this technology can effectively address certain types of difficult-to-access oil and gas resources, it provides a revolutionary technical means for the exploration and development of large-area low-porosity, low-permeability, low-pressure, and low-abundance oil and gas reservoirs, solving drilling engineering challenges, significantly increasing drilling speed, and avoiding or controlling severe lost circulation. However, wellbore cleaning is a critical issue in gas drilling. If wellbore cleaning is not improved, problems such as increased friction and pressure loss, increased torque, accelerated wear of drill strings and bits, reduced drilling speed, drill string sticking, difficulty in casing installation, and poor cementing quality can easily occur. The mechanism and laws of cuttings transport within the wellbore during gas drilling are extremely complex. When encountering a producing formation during gas drilling, both formation gas and gaseous media injected from the drill bit's water nozzles simultaneously influence cuttings transport, making the mechanism and laws of cuttings transport within the wellbore even more complex. Therefore, inventing an experimental device that simulates the laws of cuttings transport during formation gas production in gas drilling would facilitate research into these laws and help find effective measures to improve wellbore cleaning efficiency in gas drilling.

[0003] Previous research has disclosed a Chinese invention patent, "An Experimental Device and Method for Simulating Cuttings Movement in Horizontal Wells" (application number: CN103485738A), which allows for visual observation of cuttings movement in horizontal wells. This device and method can observe cuttings movement in horizontal wells under various operating conditions by changing the flow rate, drill string rotation speed, eccentricity between the drill string and the wellbore, cuttings quantity, and cuttings particle size. Chinese utility model patent CN218644246U discloses a cuttings movement simulation device for directional wells, which can be used to visually observe cuttings movement in horizontal and inclined well sections, simulating the influence of parameters such as drilling fluid viscosity and shear stress, flow rate, cuttings particle size and quantity, drill string rotation speed and eccentricity, and well inclination angle on cuttings movement in directional wells.

[0004] However, the above research has the following drawbacks:

[0005] 1. The above studies did not take into account the impact of the simultaneous action of drill bit water jetting and formation gas production on the cuttings transport law, and cannot provide a reliable basis for the problem of cuttings transport law when drill bit water jetting and formation gas production are in effect at the same time;

[0006] 2. The above-mentioned research devices have relatively complex structures and cannot realistically simulate actual working conditions. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art, this invention provides an experimental apparatus and method for simulating cuttings transport during gas drilling formation gas production. This apparatus can simulate the cuttings transport law during gas drilling formation gas production, which is beneficial for the study of cuttings transport law during gas drilling and for finding effective measures to improve wellbore purification during gas drilling formation gas production.

[0008] The specific technical solution is as follows:

[0009] The experimental setup for simulating cuttings transport during gas drilling formation gas production includes: a gas circulation system, a cuttings supply and recovery system, a drill pipe rotation and eccentricity system, a formation gas production system, and a data measurement and processing system.

[0010] Gas circulation system: includes a first air compressor, valves, and a first gas flow meter connected in sequence; a first frequency converter is connected to the first air compressor; the gas circulation system is used to simulate the gas supply problem in drilling, the first air compressor delivers gas into the wellbore, the first frequency converter and the first valve control the gas delivery volume, and the gas flow meter records gas parameters;

[0011] Cuttings supply and recovery system: includes a cuttings feeder connected to a gas flow meter, the cuttings feeder being equipped with a second frequency converter; also includes a filter connected to the air inlet of the first air compressor; the cuttings supply and recovery system simulates the cuttings production during gas drilling, filters and recovers the discharged cuttings through the filter, and controls the cuttings feed rate through the second frequency converter;

[0012] Drill pipe rotation and eccentricity system: This includes a transparent wellbore, which is a full-size wellbore. The upper half of the wellbore wall is made of transparent acrylic glass, while the lower half is made of concrete to simulate wellbore roughness. The transparent wellbore is connected to a cuttings feeder and a filter at its front and rear ends, respectively. Multiple eccentricity adjustment devices are installed on the transparent wellbore. The drill pipe is installed inside the transparent wellbore via these eccentricity adjustment devices, with a motor connected to the rear end of the drill pipe. The motor has a third frequency converter. The eccentricity adjustment device consists of an eccentric flange and a centralizer. The drill pipe is a real drill pipe, including the connecting section. The eccentricity and rotation of the drill pipe are controlled by adjusting the motor and the eccentricity adjustment devices. The drilling speed is controlled by the third frequency converter.

[0013] Formation gas production system: includes a second air compressor, a second valve, and a second gas flow meter connected in sequence. The second gas flow meter is connected to the transparent wellbore. The second air compressor produces gas to simulate the actual gas production scenario when the wellbore encounters a gas layer. The second valve controls the gas production volume, and the second gas flow meter monitors the gas flow rate.

[0014] Wellbore lifting system: includes a wellbore lifting device located at the rear end of the transparent wellbore, used to adjust the inclination angle of the transparent wellbore;

[0015] The data measurement and processing system includes a pressure gauge and ultrasonic probe mounted on the transparent wellbore, a torque sensor and a speed sensor mounted on the drill pipe, and a high-speed camera mounted on the outside of the transparent wellbore. It also includes a computer, and the pressure gauge, ultrasonic probe, torque sensor, speed sensor, high-speed camera, first frequency converter, second frequency converter, and third frequency converter are all connected to the computer. The pressure gauge measures the pressure inside the transparent wellbore; the ultrasonic probe detects the thickness of the cuttings bed generated inside the transparent wellbore during the experiment; the torque sensor measures the torque of the drill pipe; the speed sensor monitors the rotational speed of the drill pipe; and the high-speed camera captures and records the shape, trajectory, thickness, and length of the cuttings bed inside the transparent wellbore, as well as the time required for complete removal of the cuttings bed. Connecting all control devices to the computer forms a data control and acquisition system, making the entire system more intelligently controllable and facilitating operation, control, and data collection and recording.

[0016] An experimental method for simulating cuttings transport during gas drilling formation gas production, using the aforementioned experimental apparatus for simulating cuttings transport during gas drilling formation gas production, includes the following steps:

[0017] (i) Adjust the eccentricity of the drill pipe and the inclination angle of the transparent wellbore by means of the eccentric adjustment device and the wellbore lifting system.

[0018] (ii) Start the gas circulation system to supply gas to the transparent wellbore, adjust the gas flow rate, and record the flow meter reading.

[0019] (iii) Start the electric motor, control the rotary motor to adjust the speed of the drill rod, monitor the torque and speed of the drill rod, and transmit the monitoring data to the computer;

[0020] (iv) Add cuttings to the cuttings supply and recovery system, control the amount of cuttings injected, and ensure that the cuttings are evenly distributed into the transparent wellbore. Record the amount of cuttings and the injection rate. Detect the thickness of the cuttings bed;

[0021] (v) The monitor continuously photographs the transparent wellbore and automatically uploads the images to the computer. Once the experimental system is running stably, the computer records and displays the morphology, trajectory, thickness, width, length of the cuttings, the drill pipe's rotational speed and torque, and the time required for complete cuttings removal.

[0022] (vi) After the experimental records are completed, the rock fragments are collected.

[0023] (vii) Start the formation gas production system and adjust the air flow.

[0024] (viii) After the formation gas production system has been started up, repeat steps (i) to (vi);

[0025] (ix) Compare the shape, trajectory, thickness, width, length of the cuttings bed and the rotational speed and torque of the drill pipe and the time for complete removal of cuttings when the formation gas production system is turned on, and analyze the influence of formation gas production on cuttings migration.

[0026] (x) Change the eccentricity, well inclination angle, drill pipe speed, cuttings injection speed, and displacement to conduct the next set of experiments.

[0027] This invention provides an experimental apparatus and method for simulating cuttings transport during gas drilling formation production, compared to previous studies:

[0028] (1) This experimental system can simulate the movement of cuttings when gas horizontal drilling encounters gas production in the formation, providing a reliable basis for the problem of cuttings movement during formation gas production;

[0029] (2) This experimental system realizes the adjustment of drill pipe eccentricity, rotation speed and displacement, and adds wellbore lifting device to adjust wellbore inclination angle;

[0030] (3) This experimental system can simulate the movement of cuttings when gas drilling encounters gas production in the formation at different well inclination angles;

[0031] (4) The entire simulation device of the present invention has a simpler structure and lower manufacturing cost. Attached Figure Description

[0032] Figure 1 shows the experimental setup of this invention for simulating cuttings transport during gas drilling formation gas production;

[0033] Figure 2 illustrates the experimental method of this invention for simulating cuttings transport during gas drilling formation gas production. Detailed Implementation

[0034] As shown in Figure 1, the experimental setup for simulating cuttings transport during gas drilling formation gas production includes: a gas circulation system, a cuttings supply and recovery system, a drill pipe rotation and eccentricity system, a formation gas production system, and a data measurement and processing system.

[0035] Gas circulation system: includes a first air compressor 1, a valve 2, and a first gas flow meter 3 connected in sequence; a first frequency converter 20 is connected to the first air compressor 1; the gas circulation system is used to simulate the gas supply problem in drilling, and gas is delivered into the wellbore through the first air compressor 1, the first frequency converter 20 and the first valve 2 control the gas delivery volume, and the gas flow meter 3 records the gas parameters;

[0036] The cuttings supply and recovery system includes a cuttings feeder 4 connected to a gas flow meter 3, and a second frequency converter 21 is installed on the cuttings feeder 4; it also includes a filter 17 connected to the air inlet of the first air compressor 1; the cuttings supply and recovery system simulates the cuttings production during gas drilling, and filters and recovers the discharged cuttings through the filter 17, and controls the cuttings feed rate through the second frequency converter 21;

[0037] Drill pipe rotation and eccentricity system: Includes a transparent wellbore 5, which is a full-size wellbore. The upper half of the well wall is made of transparent plexiglass, while the lower half is made of cement to simulate well wall roughness. The front and rear ends of the transparent wellbore 5 are connected to a cuttings feeder 4 and a filter 17, respectively. Multiple eccentricity adjustment devices 11 are installed on the transparent wellbore 5. Drill pipe 14 is installed inside the transparent wellbore 5 via the eccentricity adjustment devices 11. The rear end of the drill pipe 14 is connected to a motor 15, which is equipped with a third frequency converter 19. The eccentricity adjustment device 11 consists of an eccentric flange and a stabilizer. The drill pipe 14 is a real drill pipe, including a drill pipe connecting section. The eccentricity and rotation of the drill pipe 14 are controlled by adjusting the motor 15 and the eccentricity adjustment devices 11. The drilling speed of the drill pipe 14 is controlled by the third frequency converter 19.

[0038] Formation gas production system: includes a second air compressor 8, a second valve 9, and a second gas flow meter 10 connected in sequence. The second gas flow meter 10 is connected to the transparent wellbore 5. The second air compressor 8 produces gas to simulate the actual gas production scenario when the wellbore encounters a gas layer. The second valve 9 controls the gas production volume, and the second gas flow meter 10 monitors the gas flow rate.

[0039] Wellbore lifting system: including wellbore lifting device 22 located at the rear end of transparent wellbore 5, used to adjust the inclination angle of transparent wellbore 5;

[0040] The data measurement and processing system includes a pressure gauge 6 and an ultrasonic probe 7 mounted on the transparent wellbore 5, a torque sensor 12 and a speed sensor 13 mounted on the drill pipe 14, and a high-speed camera 16 mounted on the outside of the transparent wellbore 5. It also includes a computer 18. The pressure gauge 6, ultrasonic probe 7, torque sensor 12, speed sensor 13, high-speed camera 16, first frequency converter 20, second frequency converter 21, and third frequency converter 19 are all connected to the computer 18. The pressure gauge 6 measures the pressure inside the transparent wellbore 5; the ultrasonic probe 7 detects the thickness of the cuttings bed generated inside the transparent wellbore 5 during the experiment; the torque sensor 12 measures the torque of the drill pipe 14; the speed sensor 13 monitors the speed of the drill pipe 14; and the high-speed camera 16 captures and records the shape, trajectory, thickness, and length of the cuttings bed inside the transparent wellbore 5, as well as the time required for complete removal of the cuttings bed. Connecting each control device to the computer 18 forms a data control and acquisition system, making the entire system more intelligently controllable and facilitating operation, control, and data collection and recording.

[0041] Figure 2 illustrates the experimental method for simulating cuttings transport during gas drilling formation gas production, including the following steps:

[0042] (a) Adjust the eccentricity of the drill pipe 14 and the inclination angle of the transparent wellbore 5 by means of the eccentric adjustment device 11 and the wellbore lifting device 22.

[0043] (ii) Start the gas circulation system to supply gas to the transparent wellbore 5, adjust the gas flow rate through the first frequency converter 20 and valve 2, and record the flow meter reading.

[0044] (iii) Start the motor 15, and adjust the rotation motor 15 by adjusting the third frequency converter 19 to adjust the rotation speed of the drill rod 14. The torque sensor 12 monitors the torque of the drill rod 14, the speed sensor 13 monitors the rotation speed of the drill rod 14, and automatically transmits the monitoring data to the computer 18.

[0045] (iv) Rock cuttings are added to the rock cuttings feeder 4, and the injection rate is controlled by the second frequency converter 21 to ensure that the rock cuttings are evenly injected into the transparent wellbore 5. The amount of rock cuttings and the injection speed are recorded. The thickness of the rock cuttings bed is detected by the ultrasonic probe 7.

[0046] (v) The high-speed camera 16 takes continuous pictures and automatically uploads them to the computer 18. After the experimental system is running stably, the computer 18 records and displays the shape, trajectory, thickness, width, length of the rock cuttings, the rotational speed and torque of the drill rod 14, and the time it takes for the rock cuttings to be completely removed.

[0047] (vi) After the experiment is completed, the rock cuttings are recycled and injected back into the rock cuttings container 4.

[0048] (vii) Start the formation gas production system, set the air compressor 8 parameters, and adjust the air flow through valve 11.

[0049] (viii) After the formation gas production system has been started up, repeat steps one to six;

[0050] (ix) Compare the shape, trajectory, thickness, width, and length of the cuttings bed, the rotational speed and torque of drill pipe 14, and the time required for complete removal of cuttings when the formation gas production system is activated, and analyze the influence of formation gas production on cuttings migration.

[0051] (x) Change the eccentricity, well inclination angle, drill pipe rotation speed, cuttings injection speed, and displacement to conduct the next set of experiments.

Claims

1. An experimental apparatus for simulating cuttings transport during gas drilling formation gas production, characterized in that, Includes: a gas circulation system, a cuttings supply and recovery system, a drill pipe rotation and eccentricity system, a formation gas production system, a wellbore lifting system, and a data measurement and processing system; the gas circulation system is used to simulate the gas supply problem during drilling; the gas circulation system includes a first air compressor (1), a first valve (2), and a first gas flow meter (3) connected in sequence; a first frequency converter (20) is connected to the first air compressor (1); gas is delivered into the wellbore through the first air compressor (1), the first frequency converter (20) and the first valve (2) control the gas delivery volume, and the first gas flow meter (3) records the gas parameters; the cuttings supply and recovery system is used to simulate the cuttings production during gas drilling and to filter and recover the discharged cuttings; The cuttings supply and recovery system includes a cuttings feeder (4) connected to a first gas flow meter (3), and a second frequency converter (21) on the cuttings feeder (4); it also includes a filter (17) connected to the air inlet of a first air compressor (1); the cuttings feeder (4) and the filter (17) are respectively connected to the front and rear ends of the transparent wellbore (5); the filter (17) filters and recovers the discharged cuttings, and controls the cuttings feed rate through the second frequency converter (21); the drill rod rotation and eccentricity system includes a transparent wellbore (5), and the front and rear ends of the transparent wellbore (5) are connected to the cuttings supply and recovery system; multiple eccentricity adjustment devices (11) are provided on the transparent wellbore (5); the drill rod is set inside the transparent wellbore (5) through the eccentricity adjustment devices (11). (14), the drill rod (14) is connected to the motor (15) at the rear end, and the motor (15) is equipped with a third frequency converter (19); the drill rod (14) is a real drill rod, including the drill rod connecting section, and the eccentricity and rotation of the drill rod (14) are controlled by adjusting the motor (15) and the eccentricity adjustment device (11); the drilling speed of the drill rod (14) is controlled by the third frequency converter (19); the formation gas production system is used to simulate the actual wellbore drilling encountering gas formation gas production scenario; the formation gas production system includes a second air compressor (8), a second valve (9), and a second gas flow meter (10) connected in sequence, and the second gas flow meter (10) is connected to the transparent wellbore (5); the second valve (9) controls the gas production, and the second gas flow meter (10) monitors the gas flow; well Tube lifting system: used to adjust the inclination angle of the transparent well tube (5) to simulate different inclination angles during actual drilling; the well tube lifting system includes a well tube lifting device (22), which is located at the rear end of the transparent well tube (5) and is used to adjust the inclination angle of the transparent well tube (5); data measurement and processing system: equipped with multiple monitors and control devices, all connected to a computer (18) to form a data control and acquisition system to achieve intelligent control; the data measurement and processing system includes a pressure gauge (6) and an ultrasonic probe (7) on the transparent well tube (5), a torque sensor (12) and a speed sensor (13) on the drill pipe (14), and a high-speed camera (16) on the outside of the transparent well tube (5);It also includes a computer (18), a pressure gauge (6), an ultrasonic probe (7), a torque sensor (12), a speed sensor (13), a high-speed camera (16), a first frequency converter (20), a second frequency converter (21), and a third frequency converter (19), all connected to the computer (18); the pressure gauge (6) measures the pressure inside the transparent wellbore (5), the ultrasonic probe (7) detects the thickness of the cuttings bed generated inside the transparent wellbore (5) during the experiment, the torque sensor (12) measures the torque of the drill rod (14), the speed sensor (13) monitors the speed of the drill rod (14), and the high-speed camera (16) captures and records the shape, trajectory, thickness, and length of the cuttings bed inside the transparent wellbore (5), as well as the time it takes for the cuttings bed to be completely cleared.

2. The experimental apparatus for simulating cuttings transport during gas drilling formation production according to claim 1, characterized in that, The transparent well casing (5) is a full-size well casing. The upper half of the well wall is made of transparent organic glass, and the lower half of the well wall is made of cement to simulate the roughness of the well wall.

3. An experimental method for simulating cuttings transport during gas drilling formation gas production, characterized in that, The experimental apparatus for simulating cuttings transport during gas drilling formation production as described in claim 1 or 2 includes the following steps: (i) adjusting the eccentricity of the drill pipe (14) and the inclination angle of the transparent wellbore (5) using the eccentric adjustment device (11) and the wellbore lifting system; (ii) starting the gas circulation system to supply gas to the transparent wellbore (5), adjusting the gas flow rate, and recording the flow meter reading; (iii) starting the motor (15), controlling the rotary motor (15) to adjust the rotation speed of the drill pipe (14), monitoring the torque and rotation speed of the drill pipe (14), and transmitting the monitoring data to the computer (18); (iv) adding cuttings to the cuttings supply and recovery system, controlling the amount of cuttings injected, and ensuring that the cuttings enter the transparent wellbore (5) evenly, recording the amount of cuttings and the injection speed; detecting the thickness of the cuttings bed; (v) monitoring The device continuously photographs the transparent wellbore (5) and automatically uploads the images to the computer (18); once the experimental system is running stably, the computer (18) records and displays the morphology, trajectory, thickness, width, length of the cuttings, the rotation speed and torque of the drill pipe (14), and the time it takes for the cuttings to be completely removed; (vi) once the experimental records are completed, the cuttings are recovered; (vii) the formation gas production system is started and the air flow is adjusted; (viii) once the formation gas production system is started, steps (i) to (vi) are repeated; (ix) the morphology, trajectory, thickness, width, length of the cuttings bed, the rotation speed and torque of the drill pipe (14), and the time it takes for the cuttings to be completely removed are compared with and without the formation gas production system, and the influence of formation gas production on cuttings migration is analyzed; (x) different eccentricities, well inclination angles, drill pipe (14) rotation speeds, cuttings injection speeds, and discharge rates are changed to conduct the next set of experiments.

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