CN109723408B

CN109723408B - Split type intelligent plunger with pulley mechanism

Info

Publication number: CN109723408B
Application number: CN201910226506.7A
Authority: CN
Inventors: 朱海燕; 张庆恺; 董润; 刘清友; 刘文全; 赵建国
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2019-03-25
Filing date: 2019-03-25
Publication date: 2021-06-15
Anticipated expiration: 2039-03-25
Also published as: CN109723408A

Abstract

The invention relates to the field of drainage and gas production of gas wells, in particular to a split type intelligent plunger with a pulley mechanism. The method is characterized in that: the intelligent plunger comprises a plunger body, a pulley mechanism at the lower end of the plunger body, a plunger sleeve, a spring slip arranged in the plunger sleeve, an opening butterfly valve with a locking device, an upper buffer, a lower buffer, a self-adaptive valve mechanism arranged in the lower buffer, and pressure, temperature and speed sensors and a microprocessor which are attached to the plunger body and the plunger sleeve, wherein the speeds of the plunger body and the plunger sleeve in the ascending or descending process are controlled by controlling the action of the pulley mechanism. Compared with the prior art, the method has the following advantages: the problem of the uncontrollable plunger speed that is used for the drainage in the continuous production operation of present not closing the well is solved, and then avoided plunger body and plunger sleeve to go upward or down the in-process effectively, take place the serious collision, cause in the pit or well head accident.

Description

Split type intelligent plunger with pulley mechanism

Technical Field

The invention relates to the field of drainage and gas production of gas fields, in particular to a split type intelligent plunger with a pulley mechanism.

Background

According to the data display of the national energy agency, the proportion of the one-time energy consumption in China is as follows: the natural gas proportion reaches 2.7% in 2003, the natural gas proportion is increased to 5.3% in 2010, and the natural gas proportion is expected to be increased to 9.8% in 2020. Therefore, under the condition of continuously emphasizing environmental protection and reducing pollution, the green water of the Qingshan mountain is the general basic regulation of the Yinshan mountain of the Jinshan mountain, the energy structure of China is continuously inclined to cleaner energy, and the demand of natural gas of China is on the rising trend. However, nearly three elements of the natural gas consumption in China depend on import from overseas, so that it is necessary to increase the total natural gas yield in China to meet the requirements of national economy and industrial development, and under the situation that the discovery of new large high-quality natural gas fields is more and more difficult at present, deep research on a natural gas yield increasing technology is needed to improve the gas yield of a single well, so that the total natural gas yield in China is increased. At present, in the exploitation of natural gas wells in China, the biggest problem restricting the continuous gas production rate of a single well is accumulated liquid in a shaft. The reason for the accumulated liquid is that during the exploitation of the gas reservoir, the gas produced in the gas well and the water and condensate oil associated with the gas mainly flow in a mist shape and liquid dropsThe form of (2) is transmitted, after the long-term exploitation, because formation pressure descends gradually, the velocity of flow of gas in the pit shaft is inevitable to be reduced, after it is less than critical liquid carrying velocity, will cause to produce cyclic annular flow in the pit shaft, and then form the slug flow, can cause the settlement of carried liquid with this, and concentrate in the pit shaft, thereby the hydrops layer in the pit shaft appears, let the output gas in the formation by the liquid seal, unable normal production that rises along the pit shaft, lead to the gas production of single well to descend by a wide margin, can force the gas well shut down even when hydrops volume is too much. And the gas well effusion exists for too long time, and the saturation of the liquid in the shaft is increased, so that the gas phase permeability is reduced, and the gas production rate and the recovery rate of a single well are greatly reduced. Therefore, the accumulated liquid is discharged by using a proper gas production and drainage technology in order to improve the yield of a single well, and the problem of accumulated liquid at the bottom of the well is very necessary to be solved. Common methods for gas production and drainage include gas lift drainage, preferably tubular column, foam drainage, mechanical pumping drainage, electric submersible pump drainage and jet pump drainage. The methods are all suitable for bottom hole drainage under different accumulated liquid amounts, and according to the data display of the national energy agency, most of gas wells in China are at the initial accumulated liquid stage at present, the accumulated liquid amount is generally not more than 50m³And/d, wherein the gas lift drainage method is mainly suitable for bottom hole drainage under the condition of the liquid accumulation amount and is used for solving the problem of liquid accumulation generated in the early stage in the shaft. The invention relates to a split type intelligent plunger with a pulley mechanism, belonging to a gas lift drainage method.

The principle of the gas lift drainage method can be summarized as follows: after the well is closed and stopped, the plunger used for draining water is lowered to the bottom of the well under the action of gravity, then the well is opened for production, the lifting force of gas in the shaft is utilized to push the plunger to drain the liquid, and the two steps are repeated all the time, so that gas production and drainage can be realized. The plungers commonly used at present are solid steel plungers, spring block type plungers, liner type plungers, wax scraping type plungers, brush type plungers, etc. Meanwhile, the water drainage by using the plunger is also an intermittent gas lift form, which is essentially a method for expanding the production pressure difference through a production stop stage and reciprocating up and down in a shaft to drain the accumulated liquid underground, such as patents US7121335B2 and CN104389782, and the advantages of the forms are that: (1) the energy in the well is fully utilized, and other energy consumption is not needed; (2) the gas-liquid interface is used as a solid interface to separate gas from liquid, so that the liquid falling back is greatly reduced; (3) the problem of the wax deposition on the well wall can be effectively reduced. However, in the actual operation, a large amount of supporting equipment needs to be equipped, and a special person needs to guard in the production process, which causes the cost of initial investment and medium-term operation to be too high, and the biggest defect is that the shut-in time for reducing the pressure in the shaft is longer and longer along with the continuous increase of the well depth, and generally if the well depth reaches 3000m, the shut-in time is at least 180 minutes, which seriously affects the gas production efficiency and the yield of a single well. In addition, if the production mode is changed into continuous operation, namely the plunger does not close the well in the descending process, the plunger cannot reach the bottom of the well due to the action of gas lift force which is generated by real-time upward channeling in the gas well, so that the problem is solved by developing a bypass type plunger or a split type plunger.

The bypass type plunger piston is internally provided with a bypass mechanism, when the plunger piston reaches the top end position and impacts the clamping device, a bypass valve in the mechanism is opened, ascending airflow passes through the channel, and therefore the plunger piston can move like a free falling body under the action of gravity; when the plunger piston descends to the bottom end position and impacts the buffer, a bypass valve in the mechanism is closed, ascending airflow does not pass through the passage, and therefore lifting force is obtained, and the accumulated liquid is lifted to ascend. However, when the conventional plunger or even the liner plunger moves in the well, the bypass valve is easily damaged or failed due to the inevitable collision with the wall of the tubing and the excessive impact force during free falling, and particularly, the problem that the plunger cannot fall to the bottom of the well, is clamped in the well or does not run upwards with liquid in actual production can be caused by the accidental opening or closing of the valve due to the excessive impact force or the excessive impact force caused by uncontrollable speed.

The novel split plunger invented by the patents US10006274B2, CN 202832414U and CN 204238911U can be summarized as follows: the plunger body and the plunger sleeve fall down successively in the descending process, the diameter of the plunger is smaller than that of the shaft, namely, gas in a well penetrates through a gap between the plunger and the shaft to form a pressure-difference-free environment, so that the descending of the plunger is equal to the movement of a free falling body, then the plunger sleeve is released at intervals, and due to the existence of a hole in the center of the sleeve, the gas in the well also penetrates through the center of the sleeve to form the pressure-difference-free environment, so that the descending of the plunger sleeve is also equal to the movement of the free falling body, and when the piston reaches the bottom of the well, the piston sleeve is combined with the plunger to seal the two mechanisms under. However, the main defects of the method are that (1) in actual operation, due to the fact that the well depth is continuously increased, in the descending process, because the plunger is always in the approximate free-falling body movement and the speed is always increased, when the plunger reaches the bottom of the well, excessive impact on a buffer at the bottom of the well is inevitably caused, so that the plunger or the buffer is damaged, even bottom-hole equipment is damaged, and serious underground accidents are caused. (2) Then, when the plunger sleeve reaches the bottom of the well, the plunger sleeve also moves in a free falling mode, the speed is increased all the time, and therefore the plunger sleeve and the plunger are inevitably locked, and the whole set of equipment is made to be invalid. (3) In the ascending process, the plunger and the plunger sleeve integrally ascend, and the plunger sleeve always ascend under the action of continuously increased difference between the lifting force and the friction force according to a dynamic model and also move in an accelerated manner, so that when the plunger and the plunger sleeve reach the top end position, the stopper is collided due to overlarge speed, the plunger or the stopper is damaged, and the potential safety hazard is very large.

In order to solve the problem that the speed of the plunger in actual gas well drainage is uncontrollable to cause serious underground accidents, the invention provides the speed-controllable intelligent plunger which has great and practical significance for the exploitation of natural gas.

Disclosure of Invention

The invention aims to solve the problem that the movement speed of a column plug in actual gas well drainage is uncontrollable, and provides a split type intelligent column plug with a pulley, so that the speed of the column plug can be controlled in real time in the ascending and descending processes, the column plug can safely and stably reach a shaft bottom or a shaft top, the damage of shaft bottom or shaft top equipment caused by excessive impact force is avoided, and the risk of underground accidents is reduced.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

the split intelligent plunger with the pulley is thrown into a well and then is driven to reach the position of the stopper, the plunger body is separated from the plunger sleeve under the action of the ejector rod on the stopper, the plunger body descends in advance, the plunger sleeve is locked at the top end position by the locking valve, then, when the speed of the plunger body reaches the optimal speed range in the descending process, the pulley mechanism is opened through signal control to cause certain friction force and continuously increase the friction force until the plunger body decelerates, when the plunger body descends to the optimal speed range, the friction force generated by the pulley is adjusted, under the detection of the sensor, the gravity, the air resistance and the friction force borne by the plunger are in a balanced state through a period of adjustment, so that the plunger body descends at a constant speed, then the calculated time point begins to increase the friction force to break the balanced state, and the plunger body continues to decelerate, after the plunger sleeve locking valve is controlled to be unlocked through a signal, the plunger sleeve which is still at the topmost position is released, when the plunger body moves to the bottommost position, the pulley mechanism is retracted, after a certain time, the free falling body of the plunger sleeve reaches the optimal speed range, the butterfly valve on the sleeve is controlled to be closed through the signal, so that gas is blocked from passing through the sleeve, pressure difference is generated below the sleeve, the lifting force is further formed, the sleeve is decelerated until the sleeve is decelerated to a reasonable range, then the butterfly valve is gradually opened through the signal, the lifting force borne by the butterfly valve is gradually reduced, a certain air resistance is still borne, the plunger sleeve is at an acceleration-deceleration alternating stage at the moment, the speed is always in a certain range and gradually decelerated to the bottommost position, after the plunger sleeve is reached, the butterfly valve is completely opened through the signal control, and is combined and sealed with the plunger body through the spring control mechanism under the action of gravity, the conical surface is used for sealing, so that the sealing performance is excellent and the clamping is not easy to occur; the whole body is in the acceleration ascending stage, and the friction force between the whole body and the pipe wall is increased, but the ascending speed of the lifting force is higher than the ascending of the friction force through a dynamic model, so the whole body still can be accelerated to ascend, when the speed reaches the optimal speed range, the pulley mechanism is released through signal control to gradually increase the friction force borne by the whole body, under the detection of a sensor, the whole body is just in a balanced state through adjustment for a period of time to do uniform ascending movement and be stabilized in the optimal speed range, and then, at the calculation position close to the well mouth, the friction force of the pulley is increased through signal control, the balance state is broken, the whole body is decelerated until the pulley moves upwards to the water outlet, the pulley is folded, and then the pulley moves upwards to the position of the topmost limiter. Later, if the sensor detects that the shaft still has the hydrops, then make whole continuation rising through signal control valve body, under the effect of ejector pin, make plunger body and plunger sleeve separate and begin the second cycle promptly, reciprocal above-mentioned process can continue to discharge the interior hydrops of shaft, and does not influence gas well output at the drainage in-process. During the whole water draining process, the exhausted air amount can be regulated via the self-adaptive valve if necessary.

The pulley mechanism is fastened with the plunger body through screw connection, and is characterized in that when the split plunger is in the process of independent downward movement and integral upward movement of the plunger body, the pulley mechanism can be released in time according to signal feedback, so that the speed of the plunger is effectively controlled, and the condition of overlarge speed is avoided.

The plunger body and the plunger sleeve can be separated or combined, and the characteristics that the movement of the plunger body and the plunger sleeve does not influence the gas production of a gas well, namely the whole drainage process does not need to shut down the well.

The spring mechanism is arranged in the plunger sleeve and is provided with a clamping groove, and the plunger mechanism is characterized in that when the plunger body and the plunger sleeve are separated or combined, the buffering performance and the sealing performance are provided, and the phenomenon of blocking is effectively avoided.

The butterfly valve mechanism is located at the center of the top end of the plunger sleeve and can adjust the opening and closing degree according to signal changes. And after the butterfly valve is completely opened, the plunger sleeve can move approximately in a free-fall mode. The self-adaptive valve is positioned in the buffer at the bottommost end and is characterized in that the size of the discharged air quantity can be adjusted through the self-adaptive valve if needed.

The conical sealing surface is positioned between the contact surfaces of the plunger body and the plunger sleeve, and is characterized in that the plunger body and the plunger sleeve can be better sealed, the sealing performance is good, and the phenomenon of blocking is not easy to occur.

The locking valve is positioned in the plunger sleeve and is characterized in that the plunger sleeve can be locked after being separated, so that the plunger sleeve cannot automatically slide under the action of gravity.

Compared with the prior art, the invention has the advantages that:

(1) the plunger can be controlled in real time in the drainage process, when the plunger moves downwards, the pulley mechanism can be released to decelerate, so that overlarge impact force caused by reaching a limit position is effectively avoided, the plunger is prevented from being damaged, and the service life of the plunger is prolonged.

(2) The movement speed of the plunger can be controlled in real time in the drainage process, when the plunger moves upwards, the ascending air quantity in a shaft can be effectively controlled by adjusting the opening and closing degree of the self-adaptive valve, so that the lifting force in the shaft is adjusted, and the friction force is increased by releasing the pulley when necessary, so that the ascending speed of the plunger is controlled to reach the optimal speed, the ascending time of the plunger is effectively shortened, and the drainage efficiency is improved; and secondly, excessive impact force caused by the fact that the plunger piston reaches the limit position is effectively avoided, the plunger piston is prevented from being damaged, and the service life of the plunger piston is prolonged.

(3) The underground accumulated liquid can be quickly discharged in real time, and the well does not need to be shut down, namely, the production of the gas well is not influenced during the drainage operation.

(4) The opening and closing of the butterfly valve, the self-adaptive valve and the self-locking valve are accurately controlled through the input and output of the microprocessor control signal, the control efficiency is increased, the overall operation efficiency is improved, and the stability and the drainage efficiency of the system are greatly enhanced.

(5) The plunger piston body and the plunger piston sleeve are sealed by conical surfaces, so that the sealing performance is excellent, and the phenomenon of blocking is not easy to occur.

Drawings

FIG. 1 is a cross-sectional view of the plunger body in combination with the plunger sleeve, shown generally upward;

FIG. 2 is a sectional view showing the plunger body and the plunger sleeve independently moving when they are respectively moved downward

FIG. 3 is a cross-sectional view of the plunger body and plunger sleeve after combination

FIG. 4 is a cross-sectional view of the plunger body separated from the plunger sleeve by the ram in the top position

FIG. 5 is a cross-sectional view of the plunger body descending at the optimum speed

FIG. 6 is a cross-sectional view of the release sheave of the plunger body traveling downward

FIG. 7 is a cross-sectional view of the plunger body descending to a certain position and releasing the plunger sleeve

FIG. 8 is a cross-sectional view of the plunger body descending to the lowermost end

FIG. 9 is a cross-sectional view of the plunger sleeve reaching the lowermost end

FIG. 10 is a cross-sectional view of the plunger body and plunger sleeve combination seal

FIG. 11 is a sectional view of the plunger body and plunger sleeve moving upward under the action of gas lifting force

FIG. 12 is a cross-sectional view of the plunger body and plunger sleeve integrated to release the pulley after the plunger body and plunger sleeve have traveled upward to an optimum speed

FIG. 13 is a cross-sectional view of the plunger body and plunger sleeve integrated to tighten the pulley when they move upward to a position close to the ram

FIG. 14 is a cross-sectional view of the plunger body and plunger sleeve integrated into the wellbore to the topmost position when fluid accumulation is detected in the wellbore

In the figure: 1. lower buffer spring, 2, lower buffer seat containing self-adaptive valve mechanism, 3, pulley mechanism, 4, plunger body, 5, plunger body sealing surface, 6, plunger ejector rod, 7, plunger sleeve, 8, sleeve sealing surface, 9, spring slip, 10, opening butterfly valve with locking device, 11, overflow port, 12, upper buffer spring, 13, limiting ejector pin, 14, limiting spring

Detailed Description

For a more complete understanding of the technical features, objects, and effects of the present invention, specific embodiments of the present invention will now be described with reference to the accompanying drawings.

Example 1: as shown in fig. 3, at the topmost end, the plunger body (4) and plunger sleeve (7) are thrown into the gas well as a whole.

Example 2: in example 1, as shown in fig. 4, the plunger body (4) is separated from the plunger sleeve (7) by the top stopper rod, and then falls first.

Example 3: on the basis of example 2, the plunger body (4) makes a free-falling movement in the wellbore until the optimal speed range calculated by the prophase dynamics model is reached, as shown in fig. 5.

Example 4: on the basis of the embodiment 3, as shown in fig. 6, after the plunger body (4) reaches the optimal speed range, the pulley mechanism (3) is released, the friction force is increased, and under the detection of a sensor, the plunger body reaches the mechanical balance after being adjusted for a period of time and moves at a constant speed.

Example 5: on the basis of the embodiment 4, as shown in fig. 7, after the plunger body (4) moves at a constant speed for a period of time, the locking butterfly valve of the plunger sleeve is controlled to unlock (10) through a signal, and then the plunger sleeve (7) is released.

Example 6: on the basis of embodiment 5, as shown in fig. 8, after the plunger body (4) descends to the bottommost end, the pulley mechanism (3) is retracted, and after the plunger sleeve (7) continuously descends to reach the optimal speed range, the butterfly valve (10) on the sleeve is controlled to be closed through a signal, so that gas is blocked from passing through the plunger sleeve (7), pressure difference is generated below the plunger sleeve (7), further lifting force is formed, the plunger sleeve (7) is decelerated until the plunger sleeve is decelerated to a reasonable range, then the butterfly valve (10) is gradually opened through the signal, so that the lifting force borne by the plunger sleeve (7) is gradually reduced, the acceleration-deceleration alternating stage is performed, and the speed is always within a certain range.

Example 7: based on the embodiment 6, as shown in fig. 9, when the plunger sleeve (7) approaches the bottommost end, the butterfly valve (10) is controlled to be fully opened through a signal.

Example 8: on the basis of embodiment 7, as shown in fig. 10, under the action of gravity, the plunger sleeve (7) is combined with the plunger body (4) at the bottommost end and forms a whole under the sealing of the spring slip (9).

Example 9: in example 8, as shown in fig. 11, the plunger body (4) and the plunger sleeve (7) as a whole move upward by the lifting force of the air pressure below the cylinder.

Example 10: on the basis of embodiment 9, as shown in fig. 12, after the plunger body (4) and the plunger sleeve (7) as a whole move upward to reach an optimal speed, the pulley mechanism (3) is released through signal control, the friction force applied to the plunger body (4) and the plunger sleeve (7) as a whole is gradually increased, and under the detection of the sensor, the force applied to the whole is just in a balanced state through adjustment for a period of time, so that the whole moves upward at a constant speed and is stabilized in an optimal speed range.

Example 11: in addition to embodiment 10, as shown in fig. 13, the plunger body (4) and the plunger sleeve (7) as a whole tighten the pulley mechanism (3) when they move upward to reach the position close to the jack.

Example 12: in addition to example 11, as shown in fig. 14, the plunger body (4) and the plunger sleeve (7) as a whole reach the stopper position, and then, if the accumulated liquid in the shaft is detected, the valve body is controlled by a signal to continuously raise the whole, and the plunger body (4) and the plunger sleeve (7) are separated by the action of the ejector rod, and the second cycle is started.

The split type intelligent plunger with the pulley provided by the invention can control the movement speed of the plunger in real time in the drainage process, and when the plunger moves downwards, the pulley mechanism can be released to decelerate, so that the excessive impact force caused by reaching the limit position is effectively avoided, the plunger is prevented from being damaged, and the service life of the plunger is prolonged. When the self-adaptive valve moves upwards, the ascending air quantity in the shaft is effectively controlled by adjusting the opening and closing degree of the self-adaptive valve, so that the lifting force in the shaft is adjusted, the pulley is released to increase the friction force if necessary, the ascending speed of the plunger is further controlled to reach the optimal speed, the ascending time of the plunger is effectively shortened, and the drainage efficiency is improved; and secondly, excessive impact force caused by the fact that the plunger piston reaches the limit position is effectively avoided, the plunger piston is prevented from being damaged, and the service life of the plunger piston is prolonged. The underground accumulated liquid can be quickly discharged in real time, and the well does not need to be shut down, namely the production of the gas well is not influenced during the drainage operation. And the microprocessor is used as a central pivot to control the input and the output of signals, so that the opening and the closing of the butterfly valve, the self-adaptive valve and the self-locking valve are accurately controlled, the control efficiency is increased, the integral operation efficiency is improved, and the stability and the drainage efficiency of the system are greatly enhanced. And the plunger piston body and the plunger piston sleeve are sealed by conical surfaces, so that the sealing performance is excellent, and the phenomenon of blocking is not easy to occur.

The above examples are merely illustrative of the embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should fall within the scope of the invention.

Claims

1. The utility model provides a take split type intelligence plunger of pulley mechanism, includes buffer spring (1) down, contains lower buffer seat (2) of self-adaptation valve mechanism, the plunger body (4), the sealed face of the plunger body (5), plunger ejector pin (6), plunger sleeve (7), the sealed face of sleeve (8), spring slips (9), take locking device's opening butterfly valve (10), overflow mouth (11), go up buffer spring (12), spacing thimble (13), spacing spring (14), its characterized in that: the split type intelligent plunger with the pulley mechanism further comprises the pulley mechanism (3), the pulley mechanism (3) is fastened with the plunger body (4) through screw connection, a signal receiver is contained in the plunger body, and the plunger body can be opened or closed according to signals.

2. The split type intelligent plunger with the pulley mechanism according to claim 1, wherein: the plunger body (4) can be separated from and combined with the plunger sleeve (7).

3. The split type intelligent plunger with the pulley mechanism according to claim 1, wherein: the spring slip (9) is arranged in the plunger sleeve (7) in a built-in mode and is provided with a clamping groove.

4. The split type intelligent plunger with the pulley mechanism according to claim 1, wherein: the opening butterfly valve (10) with the locking device is positioned at the center of the top end of the plunger sleeve (7), and the opening butterfly valve (10) with the locking device can adjust the opening and closing degree according to signal change.

5. The split type intelligent plunger with the pulley mechanism according to claim 1, wherein: the lower buffer seat (2) containing the self-adaptive valve mechanism is positioned at the bottom end, and a speed sensor is arranged in the lower buffer seat (2) containing the self-adaptive valve mechanism.

6. The split type intelligent plunger with the pulley mechanism according to claim 1, wherein: the plunger body sealing surface (5) and the sleeve sealing surface (8) are positioned between the contact surfaces of the plunger body (4) and the plunger sleeve (7), and adopt conical sealing surfaces.

7. The split type intelligent plunger with the pulley mechanism according to claim 1, wherein: the plunger sleeve (7) is internally provided with an opening butterfly valve (10) with a locking device.