A foam drainage gas extraction device and method for shale gas extraction

Abstract

The invention discloses a foam drainage gas extraction device and method for shale gas extraction, and the invention relates to the technical field of shale gas extraction, wherein a square tube connected to the lower end of the oil pipe is welded inside the lower end, and a monitoring assembly for monitoring the amount of accumulated liquid at the bottom of the wellbore is arranged between the square tube and the oil pipe, and the monitoring assembly comprises a mounting plate welded on the left side wall of the oil pipe, a sleeve ring slidably sleeved on the outside of the square tube, a pressure sensor is fixedly arranged on the bottom surface of the mounting plate, a limit plate for blocking the sleeve ring is welded on the outer wall of the lower end of the square tube, and a floating block supported on the top surface of the plugging layer is fixedly connected to the bottom of the rod; a driving assembly for dispersing effervescent tablets and agitating the flow of accumulated liquid is arranged between the limit plate and the wellbore; and a filling assembly for filling effervescent tablets into the wellbore is arranged on the left side of the upper end of the wellbore. The beneficial effects of the invention are: greatly improving the efficiency of shale gas extraction, automatically filling effervescent tablets, and greatly reducing the work intensity of workers.

Description

Technical Field

[0001] The invention relates to the technical field of shale gas exploitation, and in particular to a foam drainage gas production device and method for exploiting shale gas. Background Art

[0002] The foam drainage gas production device is indispensable in the process of shale gas extraction. The foam drainage gas production device can transport the shale gas in the production layer to the collection tank in the rear section. At the same time, it can also discharge the accumulated liquid deposited in the wellbore to improve the efficiency of shale gas extraction.

[0003] The structure of the foam drainage and gas extraction device used in a certain area is as follows: Figure 1 As shown, it comprises a wellhead blowout preventer 1, an oil pipe 2 fixedly connected to the bottom port of the wellhead blowout preventer 1, a wellbore 3 sleeved on the outside of the oil pipe 2 is fixedly arranged on the bottom surface of the wellhead blowout preventer 1, a plugging layer 4 for plugging the bottom of the wellbore 3 is constructed at the bottom of the wellbore 3, a ball valve 5 is fixedly connected to the left wall of the upper end of the wellbore 3, and a plurality of radial holes 6 located below the oil pipe 2 are opened on the outer cylindrical surface of the lower end of the wellbore 3; a valve 7 is connected to the wellhead blowout preventer 1, a shale gas output pipeline 8 is connected to the right port of the valve 7, and a collection tank is connected to the other port of the shale gas output pipeline 8.

[0004] The method of using foam drainage gas recovery equipment to collect shale gas in the production layer in this area is:

[0005] S1, using the drill bit of the drilling rig to drill on the surface layer 9, ensuring that the drill bit drills through the production layer 10, and after drilling through, controlling the drill bit of the drilling rig to move upward to recover the drill bit, thereby forming a wellbore between the production layer 10 and the surface layer 9;

[0006] S2. Workers lower the wellbore 3 into the wellbore, ensuring that the radial holes 6 of the wellbore 3 are opposite to the production layer 10, and at the same time ensuring that the wellhead blowout preventer 1 is above the surface layer 9, thereby completing the installation of the foam drainage gas production device. Figure 2 As shown;

[0007] S3. After a period of time, the shale gas in the production layer 10 enters the wellbore 3 through the radial hole 6 under gas pressure, and then the shale gas passes through the bottom port of the oil pipe 2, the inner cavity of the oil pipe 2, the wellhead blowout preventer 1, the valve 7, the shale gas output pipeline 8, and finally enters the collection tank, thereby extracting the shale gas. The flow direction of the shale gas is as follows: Figure 3 As indicated by the arrow;

[0008] After a period of exploitation, a large amount of groundwater is deposited at the bottom of the wellbore 3, and the accumulated liquid 37 blocks the radial holes 6. Figure 4 As shown, the shale gas is prevented from entering the wellbore 3, thereby reducing the shale gas extraction efficiency. At this time, the workers discharge the accumulated liquid from the bottom of the wellbore 3 in the following steps:

[0009] S31, the worker opens the ball valve 5, and puts a certain amount of effervescent tablets (the effervescent tablets are block-shaped foaming agents) into the left port of the ball valve 5. After the effervescent tablets are put into the bottom of the wellbore 3, the worker closes the ball valve 5, and the put effervescent tablets enter the bottom of the wellbore 3 and react with the accumulated liquid deposited at the bottom of the wellbore 3, and the accumulated liquid 37 turns into a large amount of low-density foam; then the shale gas that enters the wellbore 3 from the production layer 10 pushes the foam upward, and the foam and shale gas sequentially pass through the bottom port of the oil pipe 2, the inner cavity of the oil pipe 2, the wellhead blowout preventer 1, the valve 7, the shale gas output pipeline 8, and finally enter the collection tank;

[0010] S32. After waiting for a period of time, all the accumulated liquid deposited at the bottom of the wellbore 3 can be drained away, so that the subsequent shale gas can be continuously exploited.

[0011] However, although this foam drainage gas production device can produce shale gas and discharge the accumulated liquid deposited in the wellbore 3, it still has the following technical defects:

[0012] I. In step S31, after the effervescent tablets fall into the bottom of the wellbore 3, a large amount of the effervescent tablets are accumulated at the bottom of the wellbore 3 and are not in sufficient contact with the accumulated liquid, resulting in a long wait time before all the accumulated liquid is converted into foam, thereby prolonging the shale gas extraction time and greatly reducing the shale gas extraction efficiency.

[0013] II. In step S31, workers are required to put effervescent tablets into the wellbore 3 regularly or at a fixed time. That is to say, workers are specially arranged to put effervescent tablets into the wellbore 3, which undoubtedly increases the work intensity of the workers and increases the mining cost.

[0014] Therefore, there is an urgent need for a foam drainage gas extraction device and method that can greatly improve shale gas extraction efficiency, automatically add effervescent tablets, and greatly reduce the workload of workers. Summary of the invention

[0015] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a foam drainage and gas production device and method for shale gas production, which greatly improves the efficiency of shale gas production, automatically adds effervescent tablets, and greatly reduces the work intensity of workers.

[0016] The object of the present invention is achieved through the following technical scheme: a foam drainage gas production device for shale gas production, which includes a wellhead blowout preventer, an oil pipe fixedly connected to the bottom port of the wellhead blowout preventer, a wellbore sleeved on the outside of the oil pipe is fixedly arranged on the bottom surface of the wellhead blowout preventer, a plugging layer for plugging the bottom of the wellbore is constructed at the bottom of the wellbore, a ball valve is fixedly connected to the left wall of the upper end of the wellbore, and a plurality of radial holes located below the oil pipe are opened on the outer cylindrical surface of the lower end of the wellbore; a valve is connected to the wellhead blowout preventer, and a shale gas output pipeline is connected to the right port of the valve, and the lower end of the oil pipe is connected to the wellbore. A square tube connected to the wellbore is welded in the wellbore, and a monitoring assembly for monitoring the amount of liquid accumulated at the bottom of the wellbore is arranged between the square tube and the oil pipe. The monitoring assembly includes a mounting plate welded on the left side wall of the oil pipe, and a sleeve slidably sleeved on the outside of the square tube. A pressure sensor is fixedly arranged on the bottom surface of the mounting plate, and a limit plate for blocking the sleeve is welded on the outer wall of the lower end of the square tube. A rod member penetrating the sleeve is fixedly arranged at the left end of the sleeve, and a pressure head is connected to the top end of the rod member. The pressure head is located directly below the pressure sensor, and a floating block supported on the top surface of the plugging layer is fixedly connected to the bottom of the rod member.

[0017] A driving assembly for dispersing the effervescent tablet and agitating the flow of the accumulated liquid is arranged between the limit plate and the wellbore, and the driving assembly comprises a reciprocating oil cylinder fixedly arranged on the right side wall of the upper end portion of the wellbore, a guide seat fixedly arranged on the bottom surface of the limit plate, a guide rod fixedly arranged on the right end surface of the guide seat, and a movable plate slidably sleeved on the guide rod. The piston rod of the reciprocating oil cylinder passes through the wellbore, and a connecting plate is fixedly arranged on the extending end. The lower end portion of the connecting plate extends downwardly along the axial direction of the wellbore, and the extending end is fixed to the upper end portion of the movable plate. The lower end portion of the movable plate is fixedly arranged with a valve body located directly below the limit plate.

[0018] The valve body is provided with a valve cavity penetrating the right end surface thereof, a plurality of one-way valves connected to the valve cavity are fixedly provided on the top surface of the valve body, a plurality of blind grooves distributed in an array are provided on the bottom surface of the valve body, a striking rod is slidably installed in each blind groove, a spring is fixedly connected between the top surface of the striking rod and the bottom of the blind groove, and under the elastic force of the spring, the bottom of the striking rod is pressed against the plugging layer; a hose is connected to the right port of the valve cavity, the hose extends upward along the axial direction of the wellbore, and a branch pipe is connected to the extended end, the other end of the branch pipe penetrates the wellbore, and a solenoid valve is connected to the extended end, and the other port of the solenoid valve is connected to the shale gas output pipeline;

[0019] A filling assembly for filling effervescent tablets into the wellbore is arranged on the left side of the upper end of the wellbore, and the filling assembly is connected to the left port of the ball valve.

[0020] The other end of the shale gas output pipeline is connected with a collection tank.

[0021] The floating block is a foam block.

[0022] Two guide rods are fixedly arranged on the right end surface of the guide seat, and two guide holes are arranged in the movable plate. The two guide holes of the movable plate are respectively sleeved on the two guide rods.

[0023] A connector is connected to the right port of the valve cavity of the valve body, and the hose is fixedly connected to the connector.

[0024] A right platform is fixedly arranged on the right side wall of the upper end portion of the wellbore, and the cylinder body of the reciprocating oil cylinder is fixedly arranged on the top surface of the right platform.

[0025] The filling assembly includes a left platform fixed on the left side wall of the upper end of the wellbore, a silo fixed on the top surface of the left platform, and a filling cylinder fixed on the left end surface of the silo. The piston rod of the filling cylinder extends into the silo, and a push plate that slides with the inner cavity of the silo is connected to the extended end; the right port of the silo is connected to the left port of the ball valve.

[0026] The drainage and gas production device also includes a controller, which is connected to the reciprocating cylinder, the filling cylinder, the ball valve and the solenoid valve via a signal line. The pressure sensor is connected to a signal line, which runs through the upper end of the wellbore and is connected to the controller.

[0027] A method for extracting shale gas by foam drainage, comprising the following steps:

[0028] S1. The worker opens the cover on the top of the silo, and then pre-places the effervescent tablets into the inner cavity of the silo. After placement, the worker re-fixes the cover on the silo;

[0029] S2, using the drill bit of the drilling rig to drill on the surface layer, ensuring that the drill bit penetrates the production layer, and after drilling through, controlling the drill bit of the drilling rig to move upward to recover the drill bit, thereby forming a wellbore between the production layer and the surface layer;

[0030] S3. Workers lower the wellbore into the wellbore, ensuring that the radial holes of the wellbore are opposite to the production layer, and at the same time ensuring that the wellhead blowout preventer is above the surface layer, thereby completing the installation of the foam drainage gas production device;

[0031] S4. After a period of time, the shale gas in the production layer enters the wellbore through the radial holes under gas pressure, and then the shale gas passes through the bottom port of the square tube, the inner cavity of the square tube, the inner cavity of the oil pipe, the wellhead blowout preventer, the valve, the shale gas output pipeline, and finally enters the collection tank, thereby extracting the shale gas;

[0032] After a period of mining, a large amount of groundwater gradually accumulates at the bottom of the wellbore. Under the buoyancy of the accumulated liquid, the floating block of the monitoring component moves upward, the floating block drives the rod to move upward, the rod drives the sleeve to move upward along the square tube, and at the same time, the rod drives the pressure head to move toward the pressure sensor.

[0033] When the pressure head of the rod presses upward to the pressure sensor, the pressure sensor sends a pressure signal to the controller through the signal line. When the controller receives the pressure signal, it indicates that a large amount of accumulated liquid is deposited in the wellbore, which hinders the discharge of shale gas. At this time, the specific operation steps to discharge the accumulated liquid deposited at the bottom of the wellbore are as follows:

[0034] S41, the controller first controls the ball valve to start, and the ball valve is connected to the right port of the silo; then the controller controls the piston rod of the filling cylinder to extend to the right, and the piston rod drives the push plate to move to the right. When the push plate moves to the set stroke, the controller controls the filling cylinder to close; wherein, when the push plate is in motion, the effervescent tablets in the silo are pushed to the right, and the effervescent tablets in the silo pass through the right port of the silo and the ball valve in sequence, and finally fall to the bottom of the wellbore, thereby realizing automatic filling of the effervescent tablets into the wellbore;

[0035] S42, then the controller controls the piston rod of the reciprocating oil cylinder of the driving assembly to perform reciprocating telescopic motion. When the piston rod of the reciprocating oil cylinder extends to the left, the piston rod drives the movable plate to move to the left along the guide rod, the movable plate drives the valve body to move to the left, and the valve body drives the various striking rods and the one-way valve thereon to move to the left synchronously; when the piston rod of the reciprocating oil cylinder retracts to the right, the piston rod drives the movable plate to move to the right along the guide rod, the movable plate drives the valve body to move to the right, and the valve body drives the various striking rods and the one-way valve thereon to move to the right synchronously, thereby causing the striking rod to perform reciprocating left-right motion in the accumulated liquid, and the striking rod performing reciprocating left-right motion evacuates the effervescent tablets accumulated at the bottom of the wellbore to increase the contact area between the effervescent tablets and the accumulated liquid;

[0036] S43, then the controller controls the solenoid valve of the driving component to start, at which time, the shale gas flowing through the shale gas output pipeline passes through the solenoid valve, the branch pipe, the hose, the valve cavity of the valve body in sequence, and finally ejected from the top port of each one-way valve, and the upward ejected shale gas agitates the accumulated liquid to flow, thereby further increasing the contact area between the effervescent tablet and the accumulated liquid;

[0037] S44. After the effervescent tablet reacts with the accumulated liquid for a period of time, the accumulated liquid turns into a large amount of low-density foam, and then the shale gas that enters the wellbore from the production layer pushes the foam upward, and the foam and shale gas sequentially pass through the bottom port of the square tube, the inner cavity of the square tube, the inner cavity of the oil pipe, the wellhead blowout preventer, the valve, the shale gas output pipeline, and finally enter the collection tank;

[0038] S5. After waiting for a period of time, all the accumulated liquid deposited at the bottom of the wellbore can be drained away, so that the subsequent shale gas can continue to be mined.

[0039] The present invention has the following advantages: greatly improving shale gas extraction efficiency, automatically filling effervescent tablets, and greatly reducing the work intensity of workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1This is a schematic diagram of the structure of the foam drainage and gas collection device used in a certain area;

[0041] Figure 2 For example Figure 1 Schematic diagram of the installation of the foam drainage and gas production device;

[0042] Figure 3 A schematic diagram of shale gas extraction;

[0043] Figure 4 Schematic diagram of the radial hole being blocked by fluid accumulation;

[0044] Figure 5 It is a structural schematic diagram of the present invention;

[0045] Figure 6 for Figure 5 A partial enlarged view of part A;

[0046] Figure 7 It is a schematic diagram of the connection of square tube, rod, sleeve and floating block;

[0047] Figure 8 for Figure 7 The main cross-sectional diagram of

[0048] Fig. 9 It is a schematic diagram of the structure of the filling component;

[0049] Fig.10 is a schematic diagram of the structure of the drive component;

[0050] Fig.11 It is a connection diagram of the valve body, the one-way valve and the striking rod;

[0051] Fig.12 for Fig.11 The main cross-sectional diagram of

[0052] Fig.13 A schematic diagram for installing a foam drainage gas extraction device;

[0053] Fig.14 for Fig.13 A partial enlarged view of part B;

[0054] Fig.15 A schematic diagram of shale gas extraction;

[0055] Fig.16 A schematic diagram of the pressure head of the rod pressing upward onto the pressure sensor;

[0056] Fig.17 for Fig.16 A partial enlarged view of the C part;

[0057] Fig.18 A schematic diagram of automatically injecting effervescent tablets into a wellbore;

[0058] Fig.19 A schematic diagram of a striking rod evacuating the effervescent tablets accumulated at the bottom of a wellbore;

[0059] Fig. 20 for Fig.19 A partial enlarged view of the D part;

[0060] In the figure:

[0061] 1-wellhead blowout preventer, 2-oil pipe, 3-wellbore, 4-sealing layer, 5-ball valve, 6-radial hole, 7-valve, 8-shale gas output pipeline, 9-surface layer, 10-production layer;

[0062] 11-square tube, 12-ring, 13-pressure sensor, 14-limiting plate, 15-rod, 16-pressure head, 17-floating block;

[0063] 18-reciprocating cylinder, 19-guide seat, 20-guide rod, 21-movable plate, 22-connecting plate, 23-valve body, 24-valve chamber, 25-check valve, 26-strike rod, 27-spring, 28-hose, 29-branch pipe, 30-solenoid valve;

[0064] 31- filling assembly, 32- connector, 33- silo, 34- filling cylinder, 35- push plate, 36- signal line, 37- accumulated liquid. DETAILED DESCRIPTION

[0065] The present invention is further described below in conjunction with the accompanying drawings, and the protection scope of the present invention is not limited to the following:

[0066] like Figure 5~Figure 12 As shown, a foam drainage gas production device for shale gas production comprises a wellhead blowout preventer 1, an oil pipe 2 fixedly connected to the bottom port of the wellhead blowout preventer 1, a wellbore 3 sleeved on the outside of the oil pipe 2 is fixedly arranged on the bottom surface of the wellhead blowout preventer 1, a plugging layer 4 for plugging the bottom of the wellbore 3 is constructed at the bottom of the wellbore 3, a ball valve 5 is fixedly connected to the left wall of the upper end of the wellbore 3, and a plurality of radial holes 6 located below the oil pipe 2 are opened on the outer cylindrical surface of the lower end of the wellbore 3; a valve 7 is connected to the wellhead blowout preventer 1, a shale gas output pipeline 8 is connected to the right port of the valve 7, and a collection tank is connected to the other port of the shale gas output pipeline 8.

[0067] A square tube 11 connected to the lower port of the oil pipe 2 is welded inside the lower port thereof, and a monitoring assembly for monitoring the amount of liquid accumulated at the bottom of the wellbore 3 is arranged between the square tube 11 and the oil pipe 2. The monitoring assembly comprises a mounting plate welded to the left side wall of the oil pipe 2, and a collar 12 slidably sleeved on the outside of the square tube 11. A pressure sensor 13 is fixedly arranged on the bottom surface of the mounting plate, and a limit plate 14 for blocking the collar 12 is welded on the outer wall of the lower end of the square tube 11. A rod 15 penetrating the collar 12 is fixedly arranged at the left end of the collar 12, and a pressure head 16 is connected to the top end of the rod 15. The pressure head 16 is located directly below the pressure sensor 13, and a floating block 17 supported on the top surface of the plugging layer 4 is fixedly connected to the bottom of the rod 15. The floating block 17 is a foam block;

[0068] A driving assembly for dispersing the effervescent tablets and agitating the flow of the accumulated liquid is arranged between the limit plate 14 and the wellbore 3, and the driving assembly comprises a reciprocating cylinder 18 fixedly arranged on the right side wall of the upper end of the wellbore 3, a guide seat 19 fixedly arranged on the bottom surface of the limit plate 14, a guide rod 20 fixedly arranged on the right end surface of the guide seat 19, and a movable plate 21 slidably sleeved on the guide rod 20. A right platform is fixedly arranged on the right side wall of the upper end of the wellbore 3, and the cylinder body of the reciprocating cylinder 18 is fixedly arranged on the top surface of the right platform; the piston rod of the reciprocating cylinder 18 passes through the wellbore 3, and a connecting plate 22 is fixedly arranged on the extending end, the lower end of the connecting plate 22 extends downward along the axial direction of the wellbore 3, and the extending end is fixed to the upper end of the movable plate 21, and the lower end of the movable plate 21 is fixedly arranged with a valve body 23 located directly below the limit plate 14;

[0069] The valve body 23 is provided with a valve cavity 24 which passes through its right end surface, a plurality of one-way valves 25 which are connected to the valve cavity 24 are fixedly provided on the top surface of the valve body 23, a plurality of blind grooves which are distributed in an array are provided on the bottom surface of the valve body 23, a striking rod 26 is slidably installed in each blind groove, a spring 27 is fixedly connected between the top surface of the striking rod 26 and the bottom of the blind groove, and under the elastic force of the spring 27, the bottom of the striking rod 26 is pressed against the plugging layer 4; a hose 28 is connected to the right end port of the valve cavity 24, the hose 28 extends upward along the axial direction of the wellbore 3, and a branch pipe 29 is connected to the extended end, the other end of the branch pipe 29 passes through the wellbore 3, and a solenoid valve 30 is connected to the extended end, and the other end of the solenoid valve 30 is connected to the shale gas output pipeline 8; a connector 32 is connected to the right end port of the valve cavity 24 of the valve body 23, and the hose 28 is fixedly connected to the connector 32.

[0070] A filling assembly 31 for filling effervescent tablets into the wellbore 3 is provided on the left side of the upper end of the wellbore 3, and the filling assembly 31 is connected to the left port of the ball valve 5; the filling assembly 31 includes a left platform fixedly mounted on the left side wall of the upper end of the wellbore 3, a silo 33 fixedly mounted on the top surface of the left platform, and a filling cylinder 34 fixedly mounted on the left end surface of the silo 33, the piston rod of the filling cylinder 34 extends into the silo 33, and a push plate 35 is connected to the extended end to slide with the inner cavity of the silo 33; the right port of the silo 33 is connected to the left port of the ball valve 5.

[0071] Two guide rods 20 are fixedly disposed on the right end surface of the guide seat 19 , and two guide holes are opened in the movable plate 21 . The two guide holes of the movable plate 21 are respectively sleeved on the two guide rods 20 .

[0072] The drainage and gas production device also includes a controller, which is connected to the reciprocating cylinder 18, the filling cylinder 34, the ball valve 5 and the solenoid valve 30 via a signal line. The pressure sensor 13 is connected to a signal line 36, which runs through the upper end of the wellbore 3 and is connected to the controller. The controller can control the extension of the piston rod of the filling cylinder 34, and can also control the opening or closing of the ball valve 5 and the solenoid valve 30, and can also control the extension or retraction of the piston rod of the reciprocating cylinder 18.

[0073] A method for extracting shale gas by foam drainage, comprising the following steps:

[0074] S1. A worker opens the cover plate at the top of the silo 33, and then pre-places an effervescent tablet into the inner cavity of the silo 33. After placement, the worker re-fixes the cover plate on the silo 33;

[0075] S2, using the drill bit of the drilling rig to drill on the surface layer 9, ensuring that the drill bit drills through the production layer 10, and after drilling through, controlling the drill bit of the drilling rig to move upward to recover the drill bit, thereby forming a wellbore between the production layer 10 and the surface layer 9;

[0076] S3, the worker lowers the wellbore 3 into the wellbore, ensures that the radial hole 6 of the wellbore 3 is opposite to the production layer 10, and ensures that the wellhead blowout preventer 1 is above the surface layer 9, thereby completing the installation of the foam drainage gas production device. Figure 13~Figure 14 As shown;

[0077] S4. After a period of time, the shale gas in the production layer 10 enters the wellbore 3 through the radial hole 6 under gas pressure, and then the shale gas passes through the bottom port of the square tube 11, the inner cavity of the square tube 11, the inner cavity of the oil pipe 2, the wellhead blowout preventer 1, the valve 7, the shale gas output pipeline 8, and finally enters the collection tank, thereby extracting the shale gas. The flow direction of the shale gas is as follows: Fig.15 As indicated by the solid arrow;

[0078] After a period of mining, a large amount of groundwater gradually accumulates at the bottom of the wellbore 3. Under the buoyancy of the accumulated liquid, the floating block 17 of the monitoring assembly moves upward, and the floating block 17 drives the rod 15 to move upward. The rod 15 drives the sleeve 12 to move upward along the square tube 11. At the same time, the rod 15 drives the pressure head 16 to move toward the pressure sensor 13.

[0079] When the pressure head 16 of the rod 15 presses upward to the pressure sensor 13, Figure 16-17 As shown, the pressure sensor 13 sends a pressure signal to the controller via the signal line 36. When the controller receives the pressure signal, it indicates that a large amount of accumulated liquid is deposited in the wellbore 3, which hinders the discharge of shale gas. At this time, the specific operation steps for discharging the accumulated liquid deposited at the bottom of the wellbore 3 are as follows:

[0080] S41, the controller first controls the ball valve 5 to start, and the ball valve 5 is connected to the right port of the silo 33; then the controller controls the piston rod of the filling cylinder 34 to extend to the right, and the piston rod drives the push plate 35 to move to the right. When the push plate 35 moves to the set stroke, the controller controls the filling cylinder 34 to close; wherein, when the push plate 35 is in motion, the effervescent tablets in the silo 33 are pushed to the right, and the effervescent tablets in the silo 33 sequentially pass through the right port of the silo 33, the ball valve 5, and finally fall to the bottom of the wellbore 3, thereby realizing the automatic filling of the effervescent tablets into the wellbore 3. The falling direction of the effervescent tablets is as follows Fig.18 As indicated by the hollow arrow;

[0081] Among them, it can be seen from step S41 that the effervescent tablet can be automatically added to the wellbore 3 through the linkage cooperation of the floating block 17, the rod 15, the pressure sensor 13 of the monitoring component and the filling cylinder 34 of the filling component 31. Figure 1~Figure 4 The foam drainage and gas production device shown does not require workers to regularly or periodically put effervescent tablets into the wellbore 3, but automatically fills the effervescent tablets, which not only greatly reduces the work intensity of the workers, but also saves labor costs, thereby saving the cost of shale gas extraction.

[0082] S42, and then the controller controls the piston rod of the reciprocating cylinder 18 of the driving assembly to perform reciprocating telescopic motion. When the piston rod of the reciprocating cylinder 18 extends to the left, the piston rod drives the movable plate 21 to move to the left along the guide rod 20, the movable plate 21 drives the valve body 23 to move to the left, and the valve body 23 drives the various striking rods 26 and the one-way valve 25 thereon to move to the left synchronously; when the piston rod of the reciprocating cylinder 18 retracts to the right, the piston rod drives the movable plate 21 to move to the right along the guide rod 20, the movable plate 21 drives the valve body 23 to move to the right, and the valve body 23 drives the various striking rods 26 and the one-way valve 25 thereon to move to the right synchronously, thereby making the striking rod 26 perform reciprocating left and right motion in the accumulated liquid. The striking rod 26 performing reciprocating left and right motion evacuates the effervescent tablets accumulated at the bottom of the wellbore 3 to increase the contact area between the effervescent tablets and the accumulated liquid. The direction of evacuating the effervescent tablets is as follows: Figure 19~Figure 20 As indicated by the solid arrow;

[0083] S43, then the controller controls the solenoid valve 30 of the driving assembly to start. At this time, the shale gas flowing through the shale gas output pipeline 8 passes through the solenoid valve 30, the branch pipe 29, the hose 28, the valve cavity 24 of the valve body 23 in sequence, and finally ejected from the top port of each one-way valve 25. The shale gas ejected upward agitates the flow of the accumulated liquid, thereby further increasing the contact area between the effervescent tablet and the accumulated liquid. The direction of agitating the accumulated liquid is as follows: Figure 19~Figure 20 As indicated by the hollow arrow;

[0084] S44, after the effervescent tablet reacts with the accumulated liquid for a period of time, the accumulated liquid turns into a large amount of low-density foam, and then the shale gas that enters the wellbore 3 from the production layer 10 pushes the foam upward, and the foam and shale gas sequentially pass through the bottom port of the square tube 11, the inner cavity of the square tube 11, the inner cavity of the oil pipe 2, the wellhead blowout preventer 1, the valve 7, the shale gas output pipeline 8, and finally enter the collection tank;

[0085] S5. After waiting for a period of time, all the accumulated liquid deposited at the bottom of the wellbore 3 can be drained away, so that the subsequent shale gas can be continuously mined.

[0086] Among them, it can be known from steps S42 and S43 that it is only necessary to control the piston rod of the reciprocating cylinder 18 of the driving component to make a reciprocating telescopic motion, so that the various striking rods 26 on the valve body 23 can make a reciprocating left and right motion, thereby evacuating the effervescent tablets accumulated at the bottom of the wellbore 3 to increase the contact area between the effervescent tablets and the accumulated liquid; and then control the solenoid valve 30 of the driving component to start, so that the shale gas in the shale gas transmission pipeline is sequentially sprayed into the accumulated liquid through the valve body 23 and the one-way valve 25, and then the shale gas agitates the accumulated liquid to flow, thereby further increasing the contact area between the effervescent tablets and the accumulated liquid, thereby realizing the conversion of all the accumulated liquid into foam in a short time, so as to avoid the accumulated liquid blocking the radial hole 6, and ensure the smooth exploitation of the subsequent shale gas. It can be seen from this that compared with the above, the present foam drainage and gas production device is more convenient than the following ones. Figure 1~Figure 4The foam drainage gas production device shown greatly shortens the subsequent shale gas production time, thereby greatly improving the shale gas production efficiency.

[0087] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A foam drainage gas extraction device for shale gas extraction, comprising a wellhead blowout preventer (1), an oil pipe (2) fixedly connected to a bottom port of the wellhead blowout preventer (1), a wellbore (3) sleeved on the outside of the oil pipe (2) fixedly provided on the bottom surface of the wellhead blowout preventer (1), a plugging layer (4) for plugging the bottom of the wellbore (3) constructed at the bottom of the wellbore (3), a ball valve (5) fixedly connected to the left wall of the upper end of the wellbore (3), and a plurality of radial holes (6) located below the oil pipe (2) are opened on the outer cylindrical surface of the lower end of the wellbore (3); a valve (7) is connected to the wellhead blowout preventer (1), and a shale gas output pipeline (8) is connected to the right port of the valve (7), characterized in that: A square tube (11) connected to the lower end of the oil pipe (2) is welded inside the lower end thereof, and a monitoring assembly for monitoring the amount of liquid accumulated at the bottom of the wellbore (3) is arranged between the square tube (11) and the oil pipe (2), the monitoring assembly comprising a mounting plate welded to the left side wall of the oil pipe (2), and a collar (12) slidably sleeved on the outside of the square tube (11), a pressure sensor (13) being fixedly arranged on the bottom surface of the mounting plate, a limit plate (14) for blocking the collar (12) being welded to the outer wall of the lower end of the square pipe (11), a rod (15) penetrating the collar (12) being fixedly arranged at the left end of the collar (12), a pressure head (16) being connected to the top end of the rod (15), the pressure head (16) being located directly below the pressure sensor (13), and a floating block (17) supported on the top surface of the plugging layer (4) being fixedly connected to the bottom of the rod (15); A driving assembly for dispersing the effervescent tablet and agitating the flow of the accumulated liquid is arranged between the limit plate (14) and the wellbore (3), the driving assembly comprising a reciprocating cylinder (18) fixedly arranged on the right side wall of the upper end of the wellbore (3), a guide seat (19) fixedly arranged on the bottom surface of the limit plate (14), a guide rod (20) fixedly arranged on the right end surface of the guide seat (19), and a movable plate (21) slidably sleeved on the guide rod (20), the piston rod of the reciprocating cylinder (18) passes through the wellbore (3), and a connecting plate (22) is fixedly arranged on the extending end, the lower end of the connecting plate (22) extends downwardly along the axial direction of the wellbore (3), and the extending end is fixed to the upper end of the movable plate (21), and the lower end of the movable plate (21) is fixedly arranged with a valve body (23) located directly below the limit plate (14); The valve body (23) is provided with a valve cavity (24) penetrating the right end surface thereof; a plurality of one-way valves (25) in communication with the valve cavity (24) are fixedly provided on the top surface of the valve body (23); a plurality of blind grooves distributed in an array are provided on the bottom surface of the valve body (23); a striking rod (26) is slidably mounted in each blind groove; a spring (27) is fixedly connected between the top surface of the striking rod (26) and the bottom of the blind groove; under the elastic force of the spring (27), the bottom of the striking rod (26) is pressed against the plugging layer (4); a hose (28) is connected to the right end of the valve cavity (24); the hose (28) extends upward along the axial direction of the wellbore (3), and a branch pipe (29) is connected to the extended end; the other end of the branch pipe (29) penetrates the wellbore (3), and a solenoid valve (30) is connected to the extended end; the other end of the solenoid valve (30) is connected to the shale gas output pipeline (8); A filling assembly (31) for filling effervescent tablets into the wellbore (3) is provided on the left side of the upper end of the wellbore (3), and the filling assembly (31) is connected to the left port of the ball valve (5).

2. A foam drainage gas extraction device for shale gas extraction according to claim 1, characterized in that: The other end of the shale gas output pipeline (8) is connected to a collection tank.

3. A foam drainage gas extraction device for shale gas extraction according to claim 2, characterized in that: The floating block (17) is a foam block.

4. A foam drainage gas extraction device for shale gas extraction according to claim 3, characterized in that: Two guide rods (20) are fixedly arranged on the right end surface of the guide seat (19), and two guide holes are opened in the movable plate (21). The two guide holes of the movable plate (21) are respectively sleeved on the two guide rods (20).

5. A foam drainage gas extraction device for shale gas extraction according to claim 4, characterized in that: A connector (32) is connected to the right port of the valve chamber (24) of the valve body (23), and the hose (28) is fixedly connected to the connector (32).

6. A foam drainage gas extraction device for shale gas extraction according to claim 5, characterized in that: A right platform is fixedly arranged on the right side wall of the upper end of the wellbore (3), and the cylinder body of the reciprocating oil cylinder (18) is fixedly arranged on the top surface of the right platform.

7. A foam drainage gas production device for shale gas production according to claim 6, characterized in that: The filling assembly (31) comprises a left platform fixedly mounted on the left side wall of the upper end of the wellbore (3), a silo (33) fixedly mounted on the top surface of the left platform, and a filling cylinder (34) fixedly mounted on the left end surface of the silo (33); a piston rod of the filling cylinder (34) extends into the silo (33), and a push plate (35) is connected to the extended end thereof, which is slidably matched with the inner cavity of the silo (33); and a right port of the silo (33) is connected to a left port of the ball valve (5).

8. The foam drainage gas extraction device for shale gas extraction according to claim 7, characterized in that: The drainage and gas production device also includes a controller, which is connected to the reciprocating cylinder (18), the filling cylinder (34), the ball valve (5) and the solenoid valve (30) via signal lines. The pressure sensor (13) is connected to a signal line (36), which passes through the upper end of the wellbore (3) and is connected to the controller.

9. A method for shale gas production by foam drainage, using the foam drainage device for shale gas production according to claim 8, characterized in that: It includes the following steps: S1. A worker opens the cover plate at the top of the silo (33), and then pre-places an effervescent tablet into the inner cavity of the silo (33). After placement, the worker re-fixes the cover plate on the silo (33); S2, using the drill bit of the drilling rig to drill on the surface layer (9), ensuring that the drill bit penetrates the production layer (10), and after drilling through, controlling the drill bit of the drilling rig to move upward to recover the drill bit, thereby forming a wellbore between the production layer (10) and the surface layer (9); S3. Workers lower the wellbore (3) into the wellbore, ensuring that the radial hole (6) of the wellbore (3) is opposite to the production layer (10), and at the same time ensuring that the wellhead blowout preventer (1) is above the surface layer (9), thereby completing the installation of the foam drainage gas production device; S4. After a period of time, the shale gas in the production layer (10) enters the wellbore (3) through the radial holes (6) under gas pressure, and then the shale gas passes through the bottom port of the square tube (11), the inner cavity of the square tube (11), the inner cavity of the oil pipe (2), the wellhead blowout preventer (1), the valve (7), the shale gas output pipeline (8), and finally enters the collection tank, thereby extracting the shale gas; After mining for a period of time, a large amount of groundwater gradually accumulates at the bottom of the wellbore (3). Under the buoyancy of the accumulated liquid, the floating block (17) of the monitoring component moves upward, the floating block (17) drives the rod (15) to move upward, the rod (15) drives the collar (12) to move upward along the square tube (11), and at the same time, the rod (15) drives the pressure head (16) to move toward the pressure sensor (13); When the pressure head (16) of the rod (15) presses upwards onto the pressure sensor (13), the pressure sensor (13) sends a pressure signal to the controller via the signal line (36). When the controller receives the pressure signal, it indicates that a large amount of accumulated liquid that hinders the discharge of shale gas is deposited in the wellbore (3). At this time, the specific operation steps for discharging the accumulated liquid deposited at the bottom of the wellbore (3) are as follows: S41, the controller first controls the ball valve (5) to start, and the ball valve (5) is connected to the right port of the silo (33); then the controller controls the piston rod of the filling cylinder (34) to extend to the right, and the piston rod drives the push plate (35) to move to the right. When the push plate (35) moves to a set stroke, the controller controls the filling cylinder (34) to close; wherein, when the push plate (35) is moving, it pushes the effervescent tablet in the silo (33) to the right, and the effervescent tablet in the silo (33) sequentially passes through the right port of the silo (33), the ball valve (5), and finally falls into the bottom of the wellbore (3), thereby realizing automatic filling of the effervescent tablet into the wellbore (3); S42, the controller then controls the piston rod of the reciprocating cylinder (18) of the driving assembly to perform reciprocating telescopic motion. When the piston rod of the reciprocating cylinder (18) extends to the left, the piston rod drives the movable plate (21) to move to the left along the guide rod (20), the movable plate (21) drives the valve body (23) to move to the left, and the valve body (23) drives the various striking rods (26) and the one-way valve (25) thereon to move to the left synchronously; when the piston rod of the reciprocating cylinder (18) retracts to the right, When the piston rod drives the movable plate (21) to move rightward along the guide rod (20), the movable plate (21) drives the valve body (23) to move rightward, and the valve body (23) drives the striking rods (26) and the one-way valve (25) thereon to move rightward synchronously, thereby causing the striking rods (26) to make reciprocating left-right movements in the accumulated liquid. The striking rods (26) making reciprocating left-right movements evacuate the effervescent tablets accumulated at the bottom of the wellbore (3), thereby increasing the contact area between the effervescent tablets and the accumulated liquid; S43, the controller then controls the solenoid valve (30) of the driving assembly to start, at which point the shale gas flowing through the shale gas output pipeline (8) passes through the solenoid valve (30), the branch pipe (29), the hose (28), the valve cavity (24) of the valve body (23) in sequence, and is finally ejected from the top ports of each one-way valve (25), and the upwardly ejected shale gas agitates the accumulated liquid to flow, thereby further increasing the contact area between the effervescent tablet and the accumulated liquid; S44, after the effervescent tablet reacts with the accumulated liquid for a period of time, the accumulated liquid turns into a large amount of low-density foam, and then the shale gas that enters the wellbore (3) from the production layer (10) pushes the foam upward, and the foam and shale gas sequentially pass through the bottom port of the square tube (11), the inner cavity of the square tube (11), the inner cavity of the oil pipe (2), the wellhead blowout preventer (1), the valve (7), the shale gas output pipeline (8), and finally enter the collection tank; S5. After waiting for a period of time, all the accumulated liquid deposited at the bottom of the wellbore (3) can be drained away, so that the subsequent shale gas can be continuously mined.

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