Integrated wellhead hydraulic control device and method for swabbing operation of gas well

Abstract

The invention discloses an integrated wellhead hydraulic control device and method for gas well swabbing operation, the device comprises a power lifting device, a hydraulic station, a hydraulic derrick and a wellhead device connected with a gas production tree, and the wellhead device comprises an intelligent control valve, a hydraulic wellhead BOP, a blowout prevention pipe, a hydraulic blowout prevention head and a hydraulic rope feeder; the hydraulic derrick comprises a chassis hinged with a first hydraulic cylinder and rotationally connected with a ground pulley, the telescopic vertical frame is hinged with the first hydraulic cylinder and connected with the ground through a cable rope, and the top end of the telescopic vertical frame is rotationally connected with a top pulley; a steel wire rope is wound on a roller of the power lifting device, sequentially penetrates through a ground pulley, a top pulley, a hydraulic rope feeder, a hydraulic blowout prevention head, a blowout prevention pipe and a hydraulic wellhead BOP and is connected with an underground tool string in a binding mode. The hydraulic station provides power for the power lifting device, the hydraulic rope feeder, the hydraulic blowout preventer, the hydraulic wellhead BOP and the first hydraulic cylinder. According to the invention, the convenience and safety of construction are improved, and the safety and reliability of swabbing operation of the gas well are also improved.

Description

Technical Field

[0001] The invention belongs to the technical field of downhole operation in oil and gas fields, and in particular relates to an integrated wellhead hydraulic control device and method for gas well pumping operation. Background Art

[0002] In the later stage of gas well production, formation liquid continuously enters the wellbore, causing the liquid column pressure in the wellbore to increase. When the liquid column pressure exceeds the formation pressure, the gas well will lose its production capacity. Therefore, measures need to be taken to discharge the liquid in the well and restore the normal production of the gas well. Gas well pumping operation is an important technical means to solve the problem of gas well liquid accumulation and restore the gas well production capacity.

[0003] Existing wellhead devices for gas well pumping operations are usually only equipped with double-acting blowout preventers and hydraulic blowout preventers, which are used to shut down wells and prevent blowout accidents. Wellhead leakage often occurs, and most wellhead devices for gas well pumping operations rely on manual control and have a low degree of automation, resulting in low operating efficiency and poor safety. They are difficult to adapt to the pumping operation requirements under complex working conditions, which are specifically reflected in: 1) The safety and reliability of the derrick are poor, and it usually relies on external force to apply pressure on the gas tree, which is prone to safety accidents. In addition, the installation of the derrick must rely on the assistance of a crane, which has high requirements for the foundation, and is extremely inconvenient for installation and equipment migration; 2) Manual control of the blowout preventer causes serious wellhead leakage, which does not meet relevant operating standards; 3) Since the length of the downhole tool string directly affects the wellhead blowout preventer and The height design of the derrick is not adjustable, and the existing derrick length is not adjustable, so the longer the tool string is, the greater the wellhead blowout preventer and derrick height are, which increases the complexity of the device and the risk of operation; 4) The wellhead BOP is manually controlled and cannot be unmanned; 5) The wellhead is not equipped with a tool string arrival detection device. If the staff is negligent in their work and the power device is about to arrive at the wellhead, the tool string will impact the wellhead at high speed, posing a serious safety hazard. On the contrary, if the power device is stopped early, the accumulated liquid will not be removed cleanly and the drainage efficiency will be reduced; 6) The wellhead control valve is manually controlled. After the downhole tool string lifts the liquid up, if it cannot be opened in time, the accumulated liquid will be discharged from the wellhead, polluting the environment. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide an integrated wellhead hydraulic control device and method for gas well pumping operations, which not only improves the convenience and safety of construction, but also improves the safety and reliability of gas well pumping operations.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An integrated wellhead hydraulic control device for gas well pumping operation, comprising a power lifting device, a hydraulic station, a hydraulic derrick and a wellhead device;

[0007] The wellhead device includes a wellhead intelligent control valve connected to the output pipeline of the gas tree and a hydraulic wellhead BOP connected to the gas tree through a flange, a blowout preventer is fixedly connected to the hydraulic wellhead BOP, a hydraulic blowout preventer is fixedly connected to the blowout preventer, and a hydraulic rope feeder is fixedly connected to the hydraulic blowout preventer;

[0008] The hydraulic derrick comprises a basic platform and a retractable frame, a base frame is fixedly installed on the basic platform, one end of the base frame is hinged with a first hydraulic cylinder, the other end of the base frame is rotatably connected to a ground pulley, one end of the first hydraulic cylinder is hinged with the retractable frame, the retractable frame is tied with a cable wind rope, one end of the cable wind rope is anchored to the ground, and the top of the retractable frame is rotatably connected to a sky pulley;

[0009] A steel wire rope for pulling the downhole tool string is wound on the drum inside the power lifting device. One end of the steel wire rope extends out of the housing of the power lifting device, passes through the surface of the pulley and the top pulley in sequence, and then passes through the hydraulic rope feeder, the hydraulic blowout preventer, the blowout preventer and the hydraulic wellhead BOP. The tail end of the steel wire rope is connected to the downhole tool string.

[0010] The hydraulic station is connected to the driving mechanism of the power lifting device, the hydraulic rope feeder, the hydraulic blowout preventer and the hydraulic wellhead BOP and the first hydraulic cylinder through pipelines respectively.

[0011] Furthermore, at least two columns are fixedly installed on the base platform, and the top ends of the columns are fixedly connected to the base frame.

[0012] Further, the retractable frame includes a lower frame and an upper frame, the upper frame is slidably connected to the inside of the lower frame, a second hydraulic cylinder is fixedly installed at the bottom of the lower frame, the upper end of the second hydraulic cylinder is fixedly connected to the bottom of the upper frame, a crane is fixedly installed on the top of the upper frame, and the crane pulley is rotatably connected to the crane;

[0013] The lower frame and the upper frame are respectively connected with a cable wind rope, one end of the cable wind rope connected to the lower frame is tied to the column, and one end of the cable wind rope connected to the upper frame is anchored to the ground;

[0014] The second hydraulic cylinder is connected to the hydraulic station through a pipeline.

[0015] Furthermore, a tension detection device is installed on the drum of the power lifting device.

[0016] Furthermore, the hydraulic rope feeder comprises a housing and a hydraulic wire rope pressing assembly, a hydraulic motor is fixedly mounted outside the housing, and the hydraulic motor is connected to the hydraulic station through a pipeline;

[0017] Three sprockets are arranged side by side outside the housing, wherein the rotating shaft of one of the sprockets is fixedly connected to the output shaft of the hydraulic motor, the three sprockets are connected through chain transmission, and the rotating shafts of the three sprockets are fixedly connected to driving wheels;

[0018] The hydraulic wire rope clamping assembly includes two third hydraulic cylinders fixedly connected to the housing and a slider slidably connected to the inside of the housing, the third hydraulic cylinder is fixedly connected to the slider, and the third hydraulic cylinder is connected to the hydraulic station through a pipeline;

[0019] The slider is a hollow structure, and one side of the slider opposite to the driving wheel is open, and three driven wheels located in the same plane as the driving wheel are rotatably connected inside the slider;

[0020] The steel wire rope passes through the housing and is located between the driving wheel and the driven wheel.

[0021] Furthermore, the hydraulic blowout prevention head comprises an outer casing, a choke tube, a pressure inlet and an overflow port, the choke tube is threadedly connected to the lower end of the outer casing, and the outer casing is embedded with a primary filler, a secondary filler, a primary hydraulic seal and a secondary hydraulic seal;

[0022] The pressure inlet and the overflow port are connected to both sides of the outer casing respectively, the pressure inlet is connected to the hydraulic station through a pipeline, and the overflow port is connected to a flow meter;

[0023] A hydraulic oil channel is provided inside the outer casing, the hydraulic oil channel is communicated with the pressure inlet, a primary hydraulic seal and a secondary hydraulic seal are respectively located at two ends of the hydraulic oil channel, and the primary hydraulic seal and the secondary hydraulic seal both include a hydraulic piston and a packing made of elastic deformation material located at one end of the hydraulic piston;

[0024] The hydraulic piston and the center of the packing are both provided with through holes for the steel wire rope to pass through. The hydraulic piston squeezes the packing to deform it radially so as to hold the steel wire rope tightly.

[0025] Furthermore, an arrival detection device for detecting whether the downhole tool string enters or leaves the lubricant preventer is fixedly installed on the side of the lubricant preventer.

[0026] An integrated wellhead hydraulic control method for gas well pumping operation comprises the following steps:

[0027] Step 1: Level the ground on site and place the hydraulic derrick on the ground;

[0028] Step 2: Pull the wire rope connected with the tool string out from the power lifting device and pass it through the ground pulley and the top pulley in sequence;

[0029] Step 3, close the wellhead intelligent control valve, start the hydraulic station, the hydraulic station provides power to the first hydraulic cylinder, the first hydraulic cylinder pushes the retractable frame to a predetermined angle, connects the retractable frame to the ground through the cable wind rope, and then adjusts the length of the retractable frame according to the actual situation;

[0030] Step 4: When the gas well pumping operation starts, the fully sealed component of the hydraulic wellhead BOP is opened, and the hydraulic station provides power to the power lifting device, the driving mechanism of the hydraulic rope feeder and the driving mechanism of the hydraulic wellhead BOP. The fully sealed component of the hydraulic wellhead BOP is opened first, and then the wire rope is released through the power lifting device. At the same time, the hydraulic rope feeder conveys the wire rope downward to a predetermined length, and the hydraulic rope feeder releases the wire rope. The downhole tool string and the wire rope move to the set liquid level depth underground by their own weight, and then the driving mechanism of the power lifting device rotates in the opposite direction to lift the wire rope and the downhole tool string upward; repeat this step, repeatedly lift and lower the downhole tool string, and discharge the liquid inside the gas well;

[0031] The speed at which the drum of the power lifting device releases the wire rope is the same as the speed at which the hydraulic rope feeder conveys the wire rope downward;

[0032] Step 5: During the gas well pumping operation, the overflow flow of the hydraulic blowout preventer is monitored by a flow meter, and the opening of the hydraulic valve of the pipeline connecting the hydraulic station and the hydraulic blowout preventer is adjusted according to the overflow flow, thereby controlling the pressure of the hydraulic oil entering the hydraulic blowout preventer, so that the hydraulic oil holds the wire rope tightly and achieves inlet sealing;

[0033] When it is determined that the liquid level is about to reach the wellhead, the wellhead intelligent control valve is opened and its opening is adjusted according to the actual situation;

[0034] When the wellhead needs to be closed, the semi-sealed assembly of the hydraulic wellhead BOP is used to close the wellhead;

[0035] Step 6: After the gas well pumping operation is completed, the driving mechanism of the power lifting device rotates in the opposite direction, lifts up the wire rope and the downhole tool string, stores the tool string inside the blowout preventer, and closes the wellhead using the fully sealed assembly of the hydraulic wellhead BOP.

[0036] Further, the specific process of step 4 is as follows: the cylinder hydraulic station opens the fully sealed component of the hydraulic wellhead BOP, the hydraulic station provides power to the power lifting device, the hydraulic motor, the hydraulic wire rope clamping component and the hydraulic cylinder of the hydraulic wellhead, first opens the fully sealed component, then the hydraulic wire rope clamping component pushes the driven wheel to move toward the driving wheel until the surface of the driven wheel is in close contact with the wire rope, the drum of the power lifting device rotates to release the wire rope, at the same time, the hydraulic motor drives the driving wheel to rotate, and through the cooperation of the driving wheel and the driven wheel, the wire rope is conveyed downward to a predetermined length, the hydraulic wire rope clamping component drives the driven wheel to move in the opposite direction until the driven wheel and the driving wheel are away from each other, thereby releasing the wire rope, the hydraulic motor stops rotating, the tool string and the wire rope move downhole to the set liquid level depth by their own weight, and then the drum of the power lifting device reverses to lift the wire rope and the downhole tool string upward; the lifting and lowering of the downhole tool string is repeated in this way to discharge the liquid inside the gas well.

[0037] Furthermore, the specific process of step 5 is: monitoring the overflow flow of the overflow port through a flow meter, adjusting the opening of the hydraulic valve of the pipeline connecting the hydraulic station and the pressure inlet according to the overflow flow, thereby adjusting the pressing force of the hydraulic piston on the packing, so that the packing holds the wire rope tightly and realizes the wellhead sealing;

[0038] According to the detection result of the tension detection device, when it is judged that the liquid level is about to reach the wellhead, the wellhead intelligent control valve is opened and its opening is adjusted according to the actual situation;

[0039] When the wellhead needs to be closed, the hydraulic cylinder of the semi-sealing assembly of the hydraulic wellhead BOP is started through the hydraulic station, thereby driving the semi-sealing valve plate to close the wellhead.

[0040] Compared with the prior art, the present invention has the following technical effects:

[0041] Firstly, the present invention can conveniently and efficiently lower and lift the downhole tool string by conveying the tool string to the downhole through the hydraulic rope feeder, which is convenient for shortening the length of the downhole tool string, thereby reducing the height of the wellhead equipment, reducing the problem of poor stability caused by the excessive height of the equipment and the operation risk, and significantly improving the safety; secondly, the hydraulic derrick adopts an integrated design as a whole, does not require on-site construction, reduces the construction risk, and can adjust its height and inclination angle through the hydraulic cylinder, improves its applicability and the convenience of construction, migration and transportation; thirdly, the speed of releasing the wire rope by the power lifting device and the speed of conveying the wire rope by the hydraulic rope feeder can be synchronized through the control system of the hydraulic station, effectively preventing the drum from loosening the rope or the hydraulic rope feeder from slipping, thereby accurately lowering the tool string; fourthly, the anti-spray head can be controlled by the hydraulic station, which can effectively reduce the leakage of the wellhead; fifthly, the full sealing component or semi-sealing component of the hydraulic wellhead BOP can be timely started by the hydraulic station to close the wellhead, thereby improving the safety; in short, the present invention realizes the automatic control of the system, solves the problems of low automation and poor safety in the prior art, and significantly improves the efficiency and safety of gas well pumping operations.

[0042] The present invention can reduce the occurrence of tool string top collision accidents by arranging the arrival detection device on the side of the blowout preventer, and has higher safety; in addition, by real-time monitoring of the overflow flow and dynamically adjusting the output pressure of the hydraulic piston, the hydraulic blowout preventer can be always kept in a sealed state and unnecessary energy loss can be reduced.

[0043] The present invention detects the tension of the wire rope with the help of a tension detection device, and transmits the data to the control system of the hydraulic station in real time, thereby issuing instructions to the intelligent control valve to adjust its opening in real time. At the same time, the rotation speed of the drum can be adjusted according to the detected tension information, so as to control the tension within a reasonable range with high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 : Schematic diagram of the overall structure of the present invention;

[0045] Figure 2 : A front half-section structural schematic diagram of the hydraulic rope feeder of the present invention;

[0046] Figure 3 : A side structural diagram of the hydraulic rope feeder of the present invention;

[0047] Figure 4 : A schematic diagram of the half-section structure of the hydraulic spray prevention head of the present invention.

[0048] In the figure: 1, power lifting device; 2, hydraulic station; 3, hydraulic derrick; 301, basic platform; 302, bottom frame; 303, ground pulley; 304, lower frame; 305, upper frame; 306, overhead crane; 307, overhead pulley; 308, first hydraulic cylinder; 309, second hydraulic cylinder; 4, hydraulic rope feeder; 401, housing; 402, hydraulic motor; 403, hydraulic wire rope clamping assembly 404, sprocket; 405, driven wheel ; 406, chain; 407, driving wheel; 408, third hydraulic cylinder; 409, slider; 5, hydraulic blowout preventer; 501, outer casing; 502, choke tube; 503, primary packing; 504, secondary packing; 505, primary hydraulic seal; 506, secondary hydraulic seal; 507, pressure inlet; 508, overflow port; 6, blowout preventer; 601, wellhead arrival detection device; 7, hydraulic wellhead BOP; 8, wellhead intelligent control valve. DETAILED DESCRIPTION

[0049] The specific contents of the present invention are further explained in detail below in conjunction with embodiments.

[0050] like Figure 1 As shown, an integrated wellhead hydraulic control device for gas well pumping operation includes a power lifting device 1, a hydraulic station 2, a hydraulic derrick 3 and a wellhead device, wherein the wellhead device includes a hydraulic rope feeder 4, a hydraulic blowout preventer 5, a blowout preventer 6, a hydraulic wellhead BOP 7 and a wellhead intelligent control valve 8, wherein: the hydraulic rope feeder 4 is threadedly connected to the hydraulic blowout preventer 5 at the lower end, the hydraulic blowout preventer 5 is threadedly connected to the blowout preventer 6 at the lower end, the blowout preventer 6 is threadedly connected to the hydraulic wellhead BOP 7 at the lower end, the hydraulic wellhead BOP 7 is connected to the wellhead of the gas tree through a flange, the steel wire rope passes through the hydraulic rope feeder 4, the hydraulic blowout preventer 5, the blowout preventer 6 and the hydraulic wellhead BOP 7 in sequence, and the tail end of the steel wire rope is fixedly connected to a downhole tool string; the wellhead intelligent control valve 8 is connected to the output pipeline of the gas tree;

[0051] The hydraulic derrick 3 includes a basic platform 301, a base frame 302, a ground pulley 303, a lower frame 304, an upper frame 305, a crane 306, an upper pulley 307, a first hydraulic cylinder 308 and a second hydraulic cylinder 309, wherein: the basic platform 301 includes a steel plate and a plurality of columns welded to the surface of the steel plate, the columns are welded to the lower surface of the base frame 302, a first hydraulic cylinder 308 is hinged on the base frame 302, one end of the first hydraulic cylinder 308 is hinged to the lower frame 304, and the inclination angle of the lower frame 304, that is, the angle between the lower frame 304 and the base frame 302, is adjusted by the extension and contraction of the first hydraulic cylinder 308;

[0052] The columns, lower frame 304 and overhead crane 306 of the base platform 301 are all fixedly installed with locks, and the locks are tied with cables. The columns and the lower frame 304 are connected by a cable, and one end of another cable is tied to the lock of the overhead crane 306, and the other end is anchored to the ground according to the on-site conditions. The inclination angles of the lower frame 304 and the upper frame 305 are controlled by the two cables, thereby increasing the stability of the lower frame 304 and the upper frame 305;

[0053] The bottom frame 302, the lower frame 304 and the upper frame 305 are all made of profiles by K-type welding. The lower frame 304 is a hollow structure, and the inner surface of the upper frame 305 is provided with sliding rails matching the brackets around the upper frame 305, so that the upper frame 305 is slidably connected to the inside of the lower frame 304. The lower frame 304 is fixedly connected to the inside of the second hydraulic cylinder 309 parallel to its axis. One end of the second hydraulic cylinder 309 is fixedly connected to the upper frame 305. The second hydraulic cylinder 309 is extended and retracted to drive the upper frame 305 to slide back and forth along the inner wall of the lower frame 304 so as to extend into or out of the lower frame 304, thereby realizing the adjustment of the overall height of the hydraulic derrick 3, and no crane is needed, which saves costs, has high safety, and is convenient for folding and transportation;

[0054] The foundation platform 301 is composed of a steel plate and six columns, and is used to replace the existing concrete foundation for installing the derrick. No on-site construction is required, and only the ground needs to be compacted, which can greatly reduce the on-site construction workload and facilitate the migration and transportation of equipment.

[0055] The hydraulic station 2 is installed inside the housing of the power lifting device 1 and is used to provide power to the power lifting device 1, the first hydraulic cylinder 308 and the second hydraulic cylinder 309. The wire rope is wound around the drum surface of the power lifting device 1, and a tension detection device is installed on the drum.

[0056] The end of the bottom frame 302 away from the lower frame 304 is rotatably connected to the ground pulley 303, and the upper end of the upper frame 305 is fixedly installed with a crane 306, which is rotatably connected to the sky pulley 307. The steel wire rope is overlapped on the surface of the ground pulley 303 and the sky pulley 307. When the power lifting device 1 is started, the drum rotates to release the steel wire rope;

[0057] like Figure 1 to Figure 3As shown, the hydraulic rope feeder 4 includes a housing 401 and a hydraulic wire rope clamping assembly 403. A hydraulic motor 402 is fixedly installed outside the housing 401. The oil pipe of the hydraulic motor 402 is connected to the hydraulic station 2, and the hydraulic station 2 provides power to the hydraulic motor 402; three sprocket wheels 404 are arranged side by side inside the housing 401, and the rotating shaft of one sprocket wheel 406 is fixedly connected to the output shaft of the hydraulic motor 402. The three sprocket wheels 404 are connected by a chain 406, and the rotating shafts of the three sprocket wheels 404 are fixedly connected to a driving wheel 407. When the hydraulic motor 402 drives a sprocket wheel 404 fixedly connected to it to rotate, the chain 406 drives the remaining two sprocket wheels 404 to rotate, and the driving wheel 407 coaxially connected to the three sprocket wheels 404 rotates accordingly;

[0058] The hydraulic wire rope clamping assembly 403 includes two third hydraulic cylinders 408 fixedly connected to the housing 401 and a slider 409 slidably connected to the inside of the housing 401. The third hydraulic cylinder 408 is fixedly connected to the slider 409. The third hydraulic cylinder 408 is powered by the hydraulic station 2. When the third hydraulic cylinder 408 works, it drives the slider 409 to slide along the inside of the housing 401.

[0059] The slider is a hollow structure, and the slider 409 is open on one side opposite to the driving wheel 407. The slider 409 is internally rotatably connected with three driven wheels 405 located on the same plane as the driving wheel 407. When the third hydraulic cylinder 408 pushes the slider 409 to slide toward the driving wheel 407, the driven wheels 405 and the driving wheel 407 approach each other.

[0060] The steel wire rope runs through the housing 401, and the steel wire rope is located between the driving wheel 407 and the driven wheel 405, and the steel wire rope is always in contact with the surface of the driving wheel 407. When the surface of the driven wheel 405 contacts the steel wire rope, the third hydraulic cylinder 408 stops working, and the hydraulic motor 402 drives the sprocket 404 to rotate, and the driving wheel 407 coaxially connected to the sprocket 404 rotates accordingly. Since the surface of the steel wire rope contacts the driving wheel 407 and the driven wheel 405 respectively, under the action of friction, the driving wheel 407 and the driven wheel 405 rotate to transport the steel wire rope downward, and the tool string is transported to a preset position underground through the steel wire rope, generally 300m downward from the wellhead. At this time, the third hydraulic cylinder 408 drives the slider 409 to slide with the driving wheel 407 on its back, and the driven wheel 405 and the driving wheel 407 move away from each other, thereby loosening the steel wire rope, and the hydraulic motor 402 stops rotating, and the tool string and the steel wire rope move underground by their own weight;

[0061] The drum of the power lifting device 1 is provided with a speed sensor. During the process of the hydraulic rope feeder 4 conveying the steel wire rope, the speed of the drum of the power lifting device 1 is monitored in real time, and then the speed of the hydraulic motor 402 is adjusted through the electromagnetic proportional control valve inside the hydraulic station 2, so that the speed of the steel wire rope conveyed by the hydraulic rope feeder 4 matches the speed of the steel wire rope released by the power lifting device 1, so as to prevent the drum from loosening the rope or the hydraulic rope feeder 4 from slipping;

[0062] like Figure 4 As shown, the hydraulic spray prevention head 5 includes an outer casing 501, a choke tube 502, a pressure inlet 507 and an overflow port 508. The choke tube 502 is threadedly connected to the lower end of the outer casing 501. The outer casing 501 is embedded with a primary packing 503 and a secondary packing 504 as well as a primary hydraulic seal 505 and a secondary hydraulic seal 506. The pressure inlet 507 and the overflow port 508 are respectively connected to both sides of the outer casing 501, and the pressure inlet 507 is connected to the hydraulic station 2 through a pipeline.

[0063] Preferably, the primary filler 503 and the secondary filler 504 both adopt a combined embedded structure, which is easy to replace;

[0064] A hydraulic oil channel is provided inside the outer casing 501, and the hydraulic oil channel is connected to the pressure inlet 507. The primary hydraulic seal 505 and the secondary hydraulic seal 506 are respectively located at the two ends of the hydraulic oil channel. The primary hydraulic seal 505 and the secondary hydraulic seal 506 both include a hydraulic piston and a packing located at one end of the hydraulic piston. The packing is made of elastic deformation material. There are holes for the wire rope to pass through at the center of the hydraulic piston and the packing. When the hydraulic oil enters the hydraulic channel through the pressure inlet 507, it pushes the hydraulic piston to do work and squeezes the packing. The packing deforms radially and then holds the wire rope tightly, thereby sealing the inside of the outer casing 501 to prevent leakage at the wellhead.

[0065] The overflow port 508 is equipped with a flow meter. During the pumping and lifting operation, the flow meter detects the liquid flow in the overflow pipe, adjusts the output pressure of the hydraulic pump in real time, and then adjusts the pressing force of the hydraulic piston on the packing, so that the pressing force is adjustable, and the static seal is adjusted to the dynamic seal. Without affecting the pressing effect, the situation that the service life of the packing is shortened due to excessive pressing force is reduced; at the same time, the overflow port 508 is used to collect waste liquid, which reduces environmental pollution;

[0066] like Figure 1 As shown, the lubricant preventer 6 is a hollow steel pipe, which is used to accommodate the downhole tool string after the pumping operation is completed. A wellhead arrival detection device 601 is fixedly installed on the side of the lubricant preventer 6. The arrival detection device 601 adopts a magnetic field detection method to detect whether the tool string is released from or enters the lubricant preventer 6;

[0067] The hydraulic wellhead BOP 7, also known as a double-acting blowout preventer, is used to close the wellhead after the pumping operation is completed. The double-acting blowout preventer includes a full-seal component and a semi-seal component. When the tool string is lifted and stored in the lubricating preventer 6 and the wellhead needs to be closed, a pair of hydraulic cylinders control the full-seal valve plate to close the wellhead; conversely, when the tool string is in the well and the wellhead needs to be closed, another pair of hydraulic cylinders control the semi-seal valve plate to close the wellhead. A circular hole is provided in the center of the semi-seal valve plate for the wire rope to pass through.

[0068] An integrated wellhead hydraulic control method for gas well pumping operation comprises the following steps:

[0069] Step 1: Level the ground on site and place the hydraulic derrick 3 on the ground;

[0070] Step 2: Pull the wire rope connected with the tool string out from the power lifting device 1, and pass it through the ground pulley 303 and the top pulley 307 in sequence;

[0071] Step 3, close the wellhead intelligent control valve 8, start the hydraulic station 2, the hydraulic station 2 provides power to the first hydraulic cylinder 308 and the second hydraulic cylinder 309, the first hydraulic cylinder 308 pushes the lower frame 304 to a predetermined angle, and connects the lower frame 304 to the column of the base platform 301 through a cable wind rope, then the second hydraulic cylinder 309 pushes the upper frame 305 out of the lower frame 304 to a predetermined length, and one end of another cable wind rope is tied to the top of the overhead travelling crane 306, and the other end thereof is anchored to the ground according to actual conditions;

[0072] Step 4: When the gas well pumping operation begins, the full sealing assembly of the hydraulic wellhead BOP 7 is opened, and the hydraulic station 2 presses the power lifting device 1, the hydraulic motor 402, the hydraulic wire rope pressing assembly 403 and the hydraulic wellhead BOP 7. The hydraulic cylinder 407 provides power to open the full sealing component first, and then the hydraulic wire rope clamping component 403 pushes the driven wheel 405 to move toward the driving wheel 407 until the surface of the driven wheel 405 is in close contact with the wire rope, and the drum of the power lifting device 1 rotates to release the wire rope. At the same time, the hydraulic motor 402 drives the driving wheel 407 to rotate. Through the cooperation of the driving wheel 407 and the driven wheel 405, the wire rope is conveyed downward to a predetermined length. The hydraulic wire rope clamping component 403 drives the driven wheel 405 to move in the opposite direction until the driven wheel 405 and the driving wheel 407 are separated from each other, thereby releasing the wire rope, and the hydraulic motor 402 stops rotating. The tool string and the wire rope move downhole to the set liquid level depth by their own weight, and the drum of the power lifting device 1 reverses to lift the wire rope and the tool string upward; repeat step 4, repeatedly lift and lower the downhole tool string, thereby discharging the liquid inside the gas well;

[0073] Step 5: During the gas well pumping operation, the overflow flow rate of the overflow port 508 is monitored by a flow meter, and the opening of the hydraulic valve of the pipeline connecting the hydraulic station 2 and the pressure inlet 507 is adjusted according to the overflow flow rate, so as to control the pressure of the hydraulic oil entering the pressure inlet 507, so as to adjust the pressing force of the hydraulic piston on the packing, and the packing deforms along the radial direction and then holds the wire rope tightly to achieve sealing, so that there is no leakage at the wellhead;

[0074] According to the detection result of the tension detection device, when it is judged that the liquid level is about to reach the wellhead, the wellhead intelligent control valve 8 is opened and its opening is adjusted according to the actual situation;

[0075] When the wellhead needs to be closed, the wellhead is closed using the semi-closed valve plate of the hydraulic wellhead BOP 7;

[0076] Step 6: After the gas well pumping operation is completed, the drum of the power lifting device 1 is reversed, the wire rope is pulled upward, and the tool string is stored inside the blowout preventer 6;

[0077] When the wellhead needs to be closed, the wellhead is closed using the fully sealed valve plate of the hydraulic wellhead BOP 7.

[0078] On the one hand, in order to make the speed of releasing the wire rope of the power lifting device and the speed of conveying the wire rope of the hydraulic rope feeder precisely synchronized, first, set the rotation speed of the drum of the power lifting device 1 to V1, the speed of the hydraulic rope feeder 4 to V2, the flow of the hydraulic motor 402 to Q, and the opening of the electromagnetic proportional valve configured in the hydraulic station 2 to K2. By detecting the rotation speed V1 of the drum, the control current I of the electromagnetic proportional valve can be determined, thereby adjusting the opening K2 of the electromagnetic proportional valve, and controlling the flow Q of the hydraulic motor 402 through the opening K2, thereby adjusting the speed V2 of the hydraulic rope feeder 4 to match V1 and V2. The specific process is as follows:

[0079] 1) Determination of speed relationship: Since the speed V2 of the hydraulic rope feeder 4 is proportional to the input flow Q, it can be expressed as:

[0080] V2=K1.Q / q

[0081] In the formula, K1 is a dimensionless number, which is the test experience value, and q is the displacement of the hydraulic motor;

[0082] By adjusting the flow rate Q of the hydraulic motor 402, the speed V2 of the hydraulic rope feeder 4 can be precisely controlled;

[0083] 2) Adjustment of electromagnetic proportional valve: Hydraulic station 2 adjusts the flow Q of the hydraulic motor through the electromagnetic proportional valve. The core principle is based on the characteristic that the opening K2 of the electromagnetic proportional valve is proportional to the input current I. The electromagnetic proportional valve adjusts the valve body opening K2 according to the set control current I, and adjusts the flow Q of the hydraulic oil of the hydraulic motor, thereby changing the speed n of the hydraulic motor. The flow Q of the hydraulic motor is proportional to the opening K2 of the electromagnetic proportional valve, and the opening K2 of the electromagnetic proportional valve is proportional to the input current I. Therefore, the flow Q of the hydraulic motor is expressed as:

[0084] Q=K2*I

[0085] 3) Speed ​​matching control strategy: During the operation of the drum, the drum running speed V1 is monitored in real time, and the speed V2 of the hydraulic rope feeder 4 is calculated by the controller of the hydraulic station 2. According to the speed relationship, the flow Q1 of the hydraulic motor is adjusted by the electromagnetic proportional valve to make the speed V2 of the rope feeder consistent with the winch speed V1, which is expressed as:

[0086] I=V1*q / (K1*K2)

[0087] Through the above method, the hydraulic station 2 can accurately adjust the speed of the hydraulic rope feeder 4 conveying the wire rope to match the speed of the drum of the power lifting device 1 releasing the wire rope, thereby improving the operating efficiency and reliability of the system.

[0088] On the other hand, the overflow flow detected by the flow meter controls the delivery pressure of the hydraulic piston, monitors the sealing state of the hydraulic spray head 5 in real time, and realizes precise control of the sealing system. The specific process is as follows:

[0089] Two-stage packing seals (i.e., primary hydraulic seal 505 and secondary hydraulic seal 506) are arranged in the hydraulic spray head 5. The compression degree of the packing is controlled by the hydraulic piston to seal the single-strand round steel wire. The area of ​​the packing acted on by one hydraulic piston is set to S1, and the area of ​​the packing acted on by the other hydraulic piston is set to S2. The two hydraulic pistons are connected to the hydraulic station 2 by the same hydraulic pipeline. The pressure is the real-time output pressure of the hydraulic station 2. The overflow flow Qy of the overflow port 508 is monitored in real time by the flow meter. Then, the hydraulic pressure input into the hydraulic spray head 5 is controlled by the electromagnetic three-position four-way valve of the hydraulic control system to pressurize, maintain or release the hydraulic piston.

[0090] 1) According to the change of overflow flow Qy, the output pressure Ps of the hydraulic piston is dynamically adjusted, where the initial output pressure of the hydraulic piston is set to Pc. When the overflow flow Qy increases, it means that the packing is not tight enough and the output pressure Ps of the hydraulic piston needs to be increased; conversely, when the overflow flow Qy decreases, the output pressure Ps is appropriately reduced; the coefficient K is used to describe the output pressure Ps of the hydraulic piston.

[0091] 2) Calculation of coefficient K, used to describe the relationship between the hydraulic piston output pressure P and the overflow flow Qy. Assuming the change in the output pressure of the hydraulic station 2 is ΔP, K is expressed as:

[0092] K=ΔP / Qy

[0093] 3) Dynamic adjustment of output pressure: During the operation of the system, the overflow flow Qy is monitored in real time, and the output pressure Ps of the hydraulic piston is dynamically adjusted according to the proportional coefficient K, which is expressed as:

[0094] Ps=Pc+K*Qy

[0095] 4) Through the electromagnetic three-position four-way valve, the pipeline pressure corresponding to the hydraulic piston is adjusted in real time according to the required output pressure.

[0096] In the above method, the sealing state of the hydraulic blowout preventer 5 is obtained by real-time monitoring of the overflow flow, and then the output pressure of the hydraulic piston is dynamically adjusted to make the hydraulic blowout preventer 5 completely sealed. Moreover, based on the feedback of the overflow flow, the clamping force on the packing can be adjusted with high precision, which not only reduces unnecessary energy loss but also adapts to more complex working conditions.

Claims

1. An integrated wellhead hydraulic control device for gas well pumping operation, characterized in that: It comprises a power lifting device (1), a hydraulic station (2), a hydraulic derrick (3) and a wellhead device; The wellhead device comprises a wellhead intelligent control valve (8) connected to the output pipeline of the gas tree and a hydraulic wellhead BOP (7) connected to the gas tree through a flange, a blowout preventer (6) is fixedly connected to the hydraulic wellhead BOP (7), a hydraulic blowout preventer (5) is fixedly connected to the blowout preventer (6), and a hydraulic rope feeder (4) is fixedly connected to the hydraulic blowout preventer (5); The hydraulic derrick (3) comprises a base platform (301) and a retractable frame, a base frame (302) is fixedly mounted on the base platform (301), one end of the base frame (302) is hinged with a first hydraulic cylinder (308), the other end of the base frame (302) is rotatably connected to a ground pulley (303), one end of the first hydraulic cylinder (308) is hinged with the retractable frame, the retractable frame is tied with a cable wind rope, one end of the cable wind rope is anchored to the ground, and the top of the retractable frame is rotatably connected to a sky pulley (307); A steel wire rope for pulling up a downhole tool string is wound on the drum inside the power lifting device (1). One end of the steel wire rope extends out of the housing of the power lifting device (1), passes through the surfaces of the pulley (303) and the top pulley (307) in sequence, and then passes through the hydraulic rope feeder (4), the hydraulic blowout preventer (5), the blowout preventer (6) and the hydraulic wellhead BOP (7). The tail end of the steel wire rope is connected to the downhole tool string. The hydraulic station (2) is connected to the power lifting device (1), the hydraulic rope feeder (4), the hydraulic blowout preventer (5), the driving mechanism of the hydraulic wellhead BOP (7) and the first hydraulic cylinder (308) through pipelines.

2. The integrated wellhead hydraulic control device for gas well pumping operation according to claim 1, characterized in that: At least two columns are fixedly mounted on the base platform (301), and the top ends of the columns are fixedly connected to the base frame (302).

3. The integrated wellhead hydraulic control device for gas well pumping operation according to claim 1 or 2, characterized in that: The retractable frame comprises a lower frame (304) and an upper frame (305), the upper frame (305) is slidably connected to the interior of the lower frame (304), a second hydraulic cylinder (309) is fixedly installed at the bottom of the lower frame (304), the upper end of the second hydraulic cylinder (309) is fixedly connected to the bottom of the upper frame (305), a crane (306) is fixedly installed at the top of the upper frame (305), and a crane pulley (307) is rotatably connected to the crane (306); The lower frame (304) and the upper frame (305) are respectively connected with a wind rope, one end of the wind rope connected to the lower frame (304) is tied to the column, and one end of the wind rope connected to the upper frame (305) is anchored to the ground; The second hydraulic cylinder (309) is connected to the hydraulic station (2) via a pipeline.

4. The integrated wellhead hydraulic control device for gas well pumping operation according to claim 1 or 2, characterized in that: A tension detection device is installed on the roller of the power lifting device (1).

5. The integrated wellhead hydraulic control device for gas well pumping operation according to claim 4, characterized in that: The hydraulic rope feeder (4) comprises a housing (401) and a hydraulic wire rope clamping assembly (403); a hydraulic motor (402) is fixedly mounted outside the housing (401); the hydraulic motor (402) is connected to the hydraulic station (2) via a pipeline; Three sprockets (404) are arranged side by side outside the housing (401), wherein the rotating shaft of one of the sprockets (406) is fixedly connected to the output shaft of the hydraulic motor (402), the three sprockets (404) are connected by a chain (406), and the rotating shafts of the three sprockets (404) are fixedly connected to a driving wheel (407); The hydraulic wire rope clamping assembly (403) comprises two third hydraulic cylinders fixedly connected to the housing (401) and a slider slidably connected to the inside of the housing (401), the third hydraulic cylinder (408) is fixedly connected to the slider (409), and the third hydraulic cylinder (408) is connected to the hydraulic station (2) via a pipeline; The slider (409) is a hollow structure, and the side of the slider (409) opposite to the driving wheel (407) is open. The slider (409) is internally rotatably connected to three driven wheels (405) located on the same plane as the driving wheel (407); The steel wire rope passes through the housing (401) and is located between the driving wheel (407) and the driven wheel (405).

6. The integrated wellhead hydraulic control device for gas well pumping operation according to claim 5, characterized in that: The hydraulic spray prevention head (5) comprises an outer casing (501), a choke tube (502), a pressure inlet (507) and an overflow port (508); the choke tube (502) is threadedly connected to the lower end of the outer casing (501); a primary filler (503) and a secondary filler (504) as well as a primary hydraulic seal (505) and a secondary hydraulic seal (506) are embedded in the outer casing (501); The pressure inlet (507) and the overflow port (508) are respectively connected to both sides of the outer casing (501), the pressure inlet (507) is connected to the hydraulic station (2) through a pipeline, and the overflow port (508) is connected to a flow meter; A hydraulic oil channel is provided inside the outer casing (501), the hydraulic oil channel is communicated with the pressure inlet (507), a primary hydraulic seal (505) and a secondary hydraulic seal (506) are respectively located at two ends of the hydraulic oil channel, and the primary hydraulic seal (505) and the secondary hydraulic seal (506) both include a hydraulic piston and a packing made of elastic deformation material located at one end of the hydraulic piston; The hydraulic piston and the center of the packing are both provided with through holes for the steel wire rope to pass through. The hydraulic piston squeezes the packing to deform it radially so as to hold the steel wire rope tightly.

7. The integrated wellhead hydraulic control device for gas well pumping operation according to claim 6, characterized in that: An arrival detection device (601) for detecting whether a downhole tool string enters or leaves the lubricant preventer (6) is fixedly installed on the side of the lubricant preventer (6).

8. An integrated wellhead hydraulic control method for gas well pumping operation based on the device of claim 7, characterized in that: The steps include: Step 1: Level the ground on site and place the hydraulic derrick (3) on the ground; Step 2: Pull the steel wire rope connected to the tool string out of the power lifting device (1), and pass it through the ground pulley (303) and the top pulley (307) in sequence; Step 3, close the wellhead intelligent control valve (8), start the hydraulic station (2), the hydraulic station (2) provides power to the first hydraulic cylinder (308), the first hydraulic cylinder (308) pushes the retractable frame to a predetermined angle, connects the retractable frame to the ground through the cable wind rope, and then adjusts the length of the retractable frame according to the actual situation; Step 4: When the gas well pumping operation starts, the fully sealed component of the hydraulic wellhead BOP (7) is opened through the hydraulic station (2). The hydraulic station (2) provides power to the power lifting device (1), the driving mechanism of the hydraulic rope feeder (4) and the driving mechanism of the hydraulic wellhead BOP (7). The fully sealed component of the hydraulic wellhead BOP (7) is opened first, and then the wire rope is released through the power lifting device. At the same time, the hydraulic rope feeder (4) feeds the wire rope downward to a predetermined length. The hydraulic rope feeder (4) releases the wire rope, and the downhole tool string and the wire rope move downward to the set liquid level depth by their own weight. Then, the driving mechanism of the power lifting device (1) rotates in the opposite direction to lift the wire rope and the downhole tool string upward. This step is repeated to discharge the liquid inside the gas well. The speed at which the drum of the power lifting device (1) releases the steel wire rope is the same as the speed at which the hydraulic rope feeder (4) feeds the steel wire rope downward; Step 5: During the gas well pumping operation, the overflow flow of the hydraulic blowout preventer (5) is monitored by a flow meter, and the opening of the hydraulic valve of the pipeline connecting the hydraulic station (2) and the hydraulic blowout preventer (5) is adjusted according to the overflow flow, thereby controlling the pressure of the hydraulic oil entering the hydraulic blowout preventer (5) so that the hydraulic oil holds the wire rope tightly and achieves inlet sealing; When it is determined that the liquid level is about to reach the wellhead, the wellhead intelligent control valve (8) is opened and its opening is adjusted according to the actual situation; When the wellhead needs to be closed, the wellhead is closed using the semi-sealing assembly of the hydraulic wellhead BOP (7); Step 6: After the gas well pumping operation is completed, the driving mechanism of the power lifting device (1) rotates in the opposite direction, lifts the wire rope and the downhole tool string upward, stores the tool string inside the blowout preventer (6), and closes the wellhead using the fully sealed assembly of the hydraulic wellhead BOP 7.

9. The integrated wellhead hydraulic control method for gas well pumping operation according to claim 8, characterized in that: The specific process of step 4 is as follows: the fully sealed component of the hydraulic wellhead BOP (7) is opened, the hydraulic station (2) provides power to the hydraulic cylinder of the power lifting device (1), the hydraulic motor (402), the hydraulic wire rope clamping component (403) and the hydraulic cylinder of the hydraulic wellhead BOP (7), the fully sealed component is opened first, then the hydraulic wire rope clamping component (403) pushes the driven wheel (405) to move toward the driving wheel (407) until the surface of the driven wheel (405) is in close contact with the wire rope, the drum of the power lifting device (1) rotates to release the wire rope, and at the same time, the hydraulic motor (402) drives the driving wheel (407) ) rotates, and through the cooperation of the driving wheel (407) and the driven wheel (405), the steel wire rope is conveyed downward to a predetermined length, and the hydraulic steel wire rope clamping assembly (403) drives the driven wheel (405) to move in the opposite direction until the driven wheel (405) and the driving wheel (407) move away from each other, thereby loosening the steel wire rope, and the hydraulic motor (402) stops rotating. The tool string and the steel wire rope move underground to the set liquid level depth by their own weight, and then the drum of the power lifting device (1) reverses to lift the steel wire rope and the downhole tool string upward; the lifting and lowering of the downhole tool string is repeated in this way, thereby discharging the liquid inside the gas well.

10. The integrated wellhead hydraulic control method for gas well pumping operation according to claim 8, characterized in that: The specific process of step 5 is: monitoring the overflow flow of the overflow port (508) through a flow meter, adjusting the opening of the hydraulic valve of the pipeline connecting the hydraulic station (2) and the pressure inlet (507) according to the overflow flow, and adjusting the pressure of the hydraulic oil entering the pressure inlet (507), thereby adjusting the pressing force of the hydraulic piston on the packing, so that the packing holds the wire rope tightly and achieves wellhead sealing; When it is determined based on the detection result of the tension detection device that the liquid level is about to reach the wellhead, the wellhead intelligent control valve (8) is opened and its opening is adjusted according to the actual situation; When the wellhead needs to be closed, the hydraulic cylinder of the semi-sealing assembly of the hydraulic wellhead BOP (7) is started through the hydraulic station (2), thereby driving the semi-sealing valve plate to close the wellhead.

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