An oil / gas well swabbing wellhead protection system and protection method

Abstract

The present invention discloses an oil / gas well swabbing wellhead protection system and a protection method. Based on three parameters of depth, tension, and zero position provided by the wellhead protection system in real time, the position and state of the downhole instrument at the wellhead are comprehensively determined, and the winch is braked to prevent the steel cable from driving the downhole instrument to impact the blowout preventer wellhead at high speed; if there are errors in the parameters in the protection system or the monitoring device fails, the winch is braked through the protection device installed at the wellhead to prevent the steel cable from driving the downhole instrument to impact the blowout preventer wellhead at high speed; the protection device plays a role in buffering and protecting the downhole instrument, and starts the anti-top buffer protection operation control according to the tension parameter to determine the position and state of the instrument at the wellhead, thus playing a role of multiple protection; effectively preventing accidents of top-up and bottom-down impacts.

Description

Technical Field

[0001] The present invention belongs to the technical field of downhole operations in oil and gas fields, and particularly relates to an oil / gas well swabbing wellhead protection system and a protection method. Background Art

[0002] In the process of oil extraction, swabbing drainage or swabbing induced blowout is a common basic process technology for oil / gas wells and is widely used in major oil and gas fields; among them, the swabbing operation is an important link. At present, the swabbing operation mainly realizes the lifting and lowering of downhole instruments through manual operation and manual braking (stopping the drum operation for braking).

[0003] However, in the process of the swabbing operation, the following problems still exist:

[0004] The swabbing operation mainly relies on the operator's own operation experience to judge the operation; the working time is long and the labor intensity is high. The staff needs to always operate under highly concentrated attention. If the operator is negligent in work, the downhole instrument (for example, the swabbing tool) has been lifted to the wellhead without taking braking measures for braking, resulting in the steel cable driving the downhole instrument to impact the blowout preventer wellhead at high speed, colliding with the crown block, and falling to the well platform after being blocked, causing an accident of upward impact and downward smashing. In the light case, it will cause the cable to break or the instrument to be damaged, and in the heavy case, it will cause a major accident of personal injury or death.

[0005] In addition, if the operator's response is not timely, braking too early will cause the liquid in the swabbing tool to not be drained completely, affecting the swabbing efficiency; braking too late will cause the downhole instrument to collide with the blowout preventer wellhead, resulting in damage to the blowout preventer wellhead or the instrument; therefore, there are serious safety hazards, and the labor intensity of the operator is high and the production efficiency is low. Summary of the Invention

[0006] Aiming at the above defects or deficiencies, the purpose of the present invention is to provide an oil / gas well swabbing wellhead protection system and a protection method.

[0007] To achieve the above purpose, the technical solution of the present invention is as follows:

[0008] An oil / gas well swabbing wellhead protection method includes the following steps:

[0009] Step 1, controlling the downhole instrument to rise at a constant speed, and obtaining the first information and the second information in real time; and when the first information decreases and the second information decreases gradually until the first information decreases to a preset value range, proceed to Step 2;

[0010] Step 2: Control the downhole instrument to decelerate to a preset speed, rise at a constant speed, and obtain the third piece of information in real time; and when the second piece of information suddenly decreases and then decreases at a constant value, and the first piece of information is zero, verify it with the obtained third piece of information and proceed to Step 4; if the first piece of information does not reach zero, verify and calibrate it with the obtained third piece of information and proceed to Step 4.

[0011] After the second piece of information suddenly decreases and then decreases at a constant value, and the first piece of information is zero, if the third piece of information is not obtained, proceed to Step 4.

[0012] If the second piece of information increases slowly, and the first piece of information does not reach zero, and the third piece of information is not obtained, proceed to Step 3.

[0013] Step 3: Activate the anti-bumping buffer protection at the wellhead, and when the second piece of information increases to the preset limit value, give an alarm and proceed to Step 4 simultaneously.

[0014] Step 4: When the third piece of information is obtained, release the power of the winch and apply the brakes, the downhole instrument pauses. When the first piece of information is zero, directly proceed to Step 5; when the first piece of information does not reach zero, adjust the first piece of information to zero and then proceed to Step 5; when the third piece of information is not obtained, release the power of the winch and apply the brakes, the downhole instrument pauses and waits for manual handling.

[0015] Step 5: Control the downhole instrument to lower to the preset depth, then re-lift and proceed to Step 1.

[0016] In Step 4, when the third piece of information is obtained and the first piece of information does not reach zero, if the error of the first piece of information is greater than the preset value, release the power of the winch and apply the brakes, the downhole instrument pauses and waits for manual handling.

[0017] In Step 1, the first piece of information is the depth value of the downhole instrument lifted to a preset position from the wellhead, and the second piece of information is the tension value of the steel cable lifting the downhole instrument.

[0018] In Step 2, the third piece of information is the zero position signal at the preset position of the wellhead and the zeroing signal for controlling the calibration of the first piece of information.

[0019] An oil / gas well swabbing wellhead protection system includes a control system, a winch mechanism, a steel cable, a tension sensor, an optical encoder, a zero position detection device, a pulley block, and a protection device for anti-bumping buffer.

[0020] The winch mechanism is connected to the downhole instrument by a steel cable. The tension sensor is arranged on the load-bearing rope of the crown block in the pulley block. The photoelectric encoder is installed on the rotating shaft of the winch mechanism drum. The zero position detection device is installed at a preset position of the blowout preventer wellhead. The protection device is installed on the top of the blowout preventer wellhead. The control system is respectively signal-connected to the tension sensor, the photoelectric encoder, and the zero position detection device. The control system is electrically connected to the motor and the brake of the winch mechanism.

[0021] The protection device includes an upper shell and a lower shell with one end open. The upper shell and the lower shell are slidably sleeved to form a closed accommodation cavity, and a spring is arranged in the accommodation cavity.

[0022] The zero position detection device includes a winding body around which an induction coil is wound. Magnets with the same polarity facing each other are arranged at both ends of the winding body. An amplifier is also arranged at one end of the winding body, and the amplifier is electrically signal-connected to the control system.

[0023] The control system includes:

[0024] The first control module controls the downhole instrument to rise at a constant speed, and obtains the first information and the second information in real time. When the second information decreases and the first information decreases to within a preset value range, it switches to the second control module.

[0025] The second control module controls the downhole instrument to decelerate to a preset speed and rise at a constant speed, and obtains the third information in real time. When the second information suddenly decreases and then decreases at a constant value, and the first information is zero, it verifies with the obtained third information and switches to the fourth control module; if the first information does not reach zero, it verifies and calibrates with the obtained third information and switches to the fourth control module.

[0026] When the second information suddenly decreases and then decreases at a constant value, and the first information is zero but the third information is not obtained, it switches to the fourth module.

[0027] When the second information slowly increases, the first information does not reach zero, and the third information is not obtained, it switches to the third control module.

[0028] The third control module, when the acquisition of the third information fails and the second information increases to a preset limit value, releases the power of the winch and brakes, and at the same time switches to the alarm module.

[0029] The fourth control module, when the third information is obtained, releases the power of the winch and brakes, the downhole instrument pauses. When the first information is zero, it directly switches to the fifth control module. When the first information does not reach zero, it adjusts the first information to zero and then switches to the fifth module. If the error of the first information is greater than the preset value, it releases the power of the winch and brakes, the downhole instrument pauses, and waits for manual processing; when the third information is not obtained, it releases the power of the winch and brakes, the downhole instrument pauses, and waits for manual processing.

[0030] The fifth control module controls the downhole instrument to be lowered to a preset depth in the wellbore, and when the downhole instrument is lifted, it turns to step one.

[0031] The control system further includes: a control panel, the control panel is electrically connected to the control module in the control system; the control panel is electrically connected to the motor and the brake in the winch mechanism.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] The present invention provides an oil / gas well pumping wellhead protection system and a protection method. Through automatic control and an anti-top buffer protection device installed at the wellhead, the position and state of the instrument at the wellhead are comprehensively determined according to the three parameters of depth, tension, and zero position provided in real time, and the winch is braked to prevent the steel cable from driving the downhole instrument to impact the blowout preventer wellhead at high speed; if a depth monitoring failure occurs, the zero position signal issued by the zero position detection device is used as the determination basis for protection. If both the zero position detection device and the depth monitoring fail simultaneously, the wellhead protection device plays a buffer protection role for the downhole instrument, and the anti-top buffer protection operation control is started according to the tension parameter to determine the position and state of the instrument at the wellhead, thus playing a role of multiple protections; effectively preventing accidents of top-up and bottom-down impacts; at the same time, avoiding premature braking that will cause the liquid in the swab to not be completely drained, affecting the pumping efficiency; late braking will cause the instrument to collide with the blowout preventer wellhead, resulting in damage to the blowout preventer wellhead or the instrument.

[0034] In addition, it reduces the labor intensity of the staff, is conducive to making timely responses when abnormalities are found, solves the problems of slow response and fatigue work in manual operations, and overcomes potential safety hazards. Description of the Drawings

[0035] Figure 1 is the overall structural schematic diagram of an oil / gas well pumping wellhead protection system of the present invention;

[0036] Figure 2 is the flow of an oil / gas well pumping wellhead protection method of the present invention Figure 1 ;

[0037] Figure 3 is the module diagram of an oil / gas well pumping wellhead protection system of the present invention;

[0038] Figure 4 is the flow of an oil / gas well pumping wellhead protection method of the present invention Figure 2 ;

[0039] Figure 5 is the structural schematic diagram of the protection device in an oil / gas well pumping wellhead protection system of the present invention;

[0040] Figure 6 This is a schematic structural diagram of a zero position detection device in an oil / gas well pumping wellhead protection system of the present invention.

[0041] In the figure, 1 - winch mechanism; 2 - control system; 201 - first control module; 202 - second control module; 203 - third control module; 204 - fourth control module; 205 - alarm module; 206 - fifth control module; 3 - steel cable; 4 - tension sensor; 5 - protection device; 501 - upper housing; 502 - lower housing; 503 - spring; 6 - depth sensor; 7 - zero position sensor; 701 - winding body; 702 - induction coil; 703 - magnet; 704 - amplifier; 705 - central through hole; 8 - downhole instrument; 9 - wellbore; 10 - crown block; 11 - traveling block; 12 - blowout preventer wellhead; 13 - oil production bypass. Specific embodiments

[0042] The following will describe the present invention in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. An oil / gas well pumping wellhead protection system and protection method

[0043] Embodiment 1: As Figure 2 , Figure 4 shown, it shows a flowchart of an embodiment of an oil / gas well pumping wellhead protection method of the present invention. This oil / gas well pumping wellhead protection method is used in the control system 2 and includes:

[0044] Step 1, control the downhole instrument 8 to rise at a constant speed, and obtain the first information and the second information in real time. The first information is the depth value of the lifted downhole instrument 8 from the preset position of the wellhead, and the second information is the tension value of the steel cable 3 of the lifted downhole instrument 8. And when the first information decreases and the second information decreases until the first information decreases to the preset value range, go to Step 2;

[0045] Step 2, control the downhole instrument 8 to decelerate to the preset speed, rise at a constant speed, and obtain the third information in real time. The third information is the zero position signal at the preset position of the wellhead and the zeroing signal for calibrating the first information. And when the second information suddenly decreases and then decreases at a constant value, and the first information is zero, verify with the obtained third information and go to Step 4; if the first information does not reach zero, verify and calibrate with the obtained third information and go to Step 4;

[0046] When the second information suddenly decreases and then decreases at a constant value, and the first information is zero, and the third information is not obtained, go to Step 4;

[0047] The second information increases gradually, the first information does not reach zero, and the third information is not obtained. Go to Step 3;

[0048] Step 3: The anti - top - buffer protection at the wellhead is activated. When the second information increases to the preset limit value, an alarm is given, and at the same time, go to Step 4;

[0049] Step 4: When the third information is obtained, the power of the winch is released and the brakes are applied. The downhole instrument 8 pauses. When the first information is zero, directly go to Step 5. When the first information does not reach zero (there is an error), after adjusting the first information to zero, go to Step 5. If the error of the first information is greater than the preset value, release the power of the winch and apply the brakes. The downhole instrument 8 pauses and waits for manual processing. When the third information is not obtained (the acquisition of the third information fails), release the power of the winch and apply the brakes. The downhole instrument 8 pauses and waits for manual processing;

[0050] Step 5: Control the downhole instrument 8 to be lowered to the preset depth. When the downhole instrument 8 is re - lifted and rises at a constant speed, go to Step 1.

[0051] Furthermore, in Step 3, the protection device for anti - top buffering is compressed by the rising downhole instrument. When the second information increases to the preset limit value, the system gives an alarm, automatically releases the power of the winch and applies the brakes, and waits for manual processing.

[0052] In the above embodiments, the downhole instrument 8 is lifted by the wireline 3. When the control system 2 is in the pumping operation, it monitors the state of the downhole instrument 8 in the wellbore 9 by monitoring the tension value of the wireline 3, the depth value of the downhole instrument 8 from the preset position at the wellhead, and the zero position signal when the downhole instrument 8 enters the preset position at the wellhead. When the first information decreases, that is, the downhole instrument 8 is getting closer to the preset position at the wellhead during ascent, and the second information decreases, that is, the tension value of the wireline 3 is always a steadily decreasing value with the lifting speed, at this time, the downhole instrument 8 ascends uniformly in the wellbore; when the decreasing amplitude of the second information decreases, the downhole instrument ascends uniformly in the wellbore 9. In particular, when the downhole instrument 8 drives the accumulated fluid to rise through the oil production bypass 13 at the blowout preventer wellhead, when the accumulated fluid is discharged from the bypass to the wellhead zero position and all the accumulated fluid is discharged, there is an instantaneous attenuation process of the second information during this process, until the second information decreases at a constant value, and the downhole instrument 8 rises to the preset position (zero position) of the blowout preventer wellhead; when the second information increases slowly, that is, the tension value of the wireline 3 gradually increases, the downhole instrument 8 rises beyond the preset position (zero position) at the wellhead and contacts the upper protection device 5, squeezing the protection device 5 until the second information increases to the preset limit value and an alarm is given, and at the same time, the power of the winch is released and the brake is applied, and the downhole instrument 8 pauses and waits for manual processing. Exemplarily, when it is displayed on the control panel that the downhole instrument 8 is at a position 20 - 30 meters from the preset position at the wellhead, the control system 2 controls the winch mechanism 1 to reduce the speed to a constant speed of 0.5 - 0.7 m / s.

[0053] When the accumulated fluid is discharged, after the second information suddenly decreases and then decreases at a constant value, the first information is a zero value, and at the same time, the third information (the zero position signal of the downhole instrument 8 from the preset position at the wellhead) is obtained, that is, the downhole instrument 8 enters the preset wellhead zero position. At this time, the control system 2 releases the power of the winch and applies the brake through the operation panel, and then controls the downhole instrument 8 to be lowered to the preset depth, and repeats the above actions in sequence and cycles.

[0054] When the accumulated fluid is discharged, after the second information suddenly decreases and then decreases at a constant value, the first information does not reach a zero value, and the third information is obtained, that is, the downhole instrument 8 enters the preset position at the wellhead, but there is an accumulated error during the lowering and lifting processes of the downhole instrument 8. When the third information is obtained, the power of the winch is released and the brake is applied, and the downhole instrument 8 pauses. After the obtained zero position signal is used to adjust the first information to zero through the control panel, the downhole instrument 8 is controlled to be lowered to the preset depth, and the actions in step one are repeated.

[0055] When the accumulated fluid is discharged, after the second information suddenly decreases and then decreases at a constant value, the first information is a zero value, and the third information is not obtained, that is, the downhole instrument 8 enters the preset position at the wellhead, and the zero position detection device 7 fails. The control system 2 obtains the first information zeroing signal, releases the power of the winch and applies the brake, and the downhole instrument 8 pauses and waits for manual processing.

[0056] When the liquid accumulation is discharged, the second information increases gradually, the first information does not reach zero, and the third information is not obtained at the same time, that is, there is data loss or cumulative error during the lowering and lifting of the downhole instrument 8. At the same time, the zero position detection device fails, and the control system 2 does not receive the third information (zero position signal). The downhole instrument 8 exceeds the preset position (zero position) and contacts the protection device 5, resulting in extrusion. The wellhead anti-top buffer protection is activated. And when the second information increases to the preset limit value (the maximum tension value that can be borne plus the safety factor), the control system 2 issues an alarm, simultaneously releases the winch power and brakes, the downhole instrument 8 pauses, and waits for manual processing. Through the issued alarm, the on-site personnel are reminded to carry out maintenance, thus effectively and timely preventing accidents of top-up and bottom-down during the swabbing operation.

[0057] Embodiment 2, as Figure 1 shown, which shows the overall structural schematic diagram of the oil / gas well swabbing wellhead protection system of the present invention. The oil / gas well swabbing wellhead protection system includes:

[0058] A control system 2, which is used to run an oil / gas well swabbing wellhead protection method in Embodiment 1;

[0059] A winch mechanism 1: used for winding a steel cable on a drum to lift or tow a downhole instrument 8, which mainly includes a drum, a winch frame, a braking device, and a winch power device. Exemplarily, the winch power device is a motor or a hydraulic motor; the power output end of the motor is in transmission connection with the drum, the drum is installed on the winch frame, and the braking device is in contact connection with the drum; the motor acts on the drum to provide power for the up or down movement of the downhole instrument 8, and the braking device provides braking force for the up-moving downhole instrument 8;

[0060] A steel cable 3;

[0061] A tension sensor 4: provides the tension change of the steel cable 3 during the hoisting of the downhole instrument;

[0062] A protection device 5 for anti-top buffer protection; when the zero position signal of the downhole instrument fails to be obtained, it provides buffer protection for the downhole instrument, decelerates until the downhole instrument 8 stops, ensuring safety;

[0063] An optical encoder 6; provides the real-time depth value during the up or down movement of the downhole instrument 8; consists of a grating disk and an optoelectronic detection device, and is a sensor that converts the mechanical geometric displacement on the output shaft into pulses or digital quantities through optoelectronic conversion (can convert and calculate the depth of the up or down movement of the downhole instrument); the real-time depth value is displayed on the winch panel. At the same time, the control system 2 is electrically connected to the optical encoder 6. When the depth value is zero, the control system controls the winch mechanism 1 to release the power and brake.

[0064] Zero position detection device 7; used to monitor in real time the zero position signal when the downhole instrument 8 rises to the preset position at the wellhead; the control system 2 releases the power of the winch and brakes through the received zero position signal to pause the downhole instrument 8; at the same time, the control system 2 controls the photoelectric encoder 6 to reset the depth to zero, so as to reset the first information (depth value) and eliminate errors.

[0065] The winch mechanism 1 is connected to the downhole instrument 8 through a steel cable 3. The tension sensor 4 is arranged on the load-bearing rope of the crown block 10 in the pulley block. The grating disk of the photoelectric encoder 6 is installed on the rotating shaft of the drum of the winch mechanism 1. The zero position detection device 7 is installed at the preset position of the blowout preventer wellhead 12. The control system 2 is respectively connected to the tension sensor 4, the photoelectric encoder 6, and the zero position detection device 7 through electrical signals or wireless signals. The control system 2 is electrically connected to the motor and brake of the winch mechanism 1; the protection device 5 is installed at the top of the blowout preventer wellhead 12. It should be noted that the steel cable 3 passes through the central hole of the protection device 5 and is connected to the downhole instrument 8.

[0066] In the above embodiment, the control system 2 runs the protection method in Embodiment 1. The control system 2 obtains the signals of the photoelectric encoder 6, the tension sensor 4, and the zero position detection device 7, and comprehensively determines the position and state of the instrument at the wellhead according to the three parameters of depth, tension, and zero position provided in real time, and conducts wellhead protection operation control on the winch mechanism 1; if the zero position detection device 7 in the wellbore 9 fails, when the depth value monitored in real time by the photoelectric encoder 6 is zero, the power is released and the brake is applied in time through the control system 2; if there is an accumulated error in the depth value, the protection device 5 plays a role of buffering and protecting the downhole instrument 8, and starts the anti-top buffering protection operation control according to the parameters of depth, tension, and the zero position signal at the preset position to determine the position and state of the instrument 8 at the wellhead, playing a multiple protection function; for the specific implementation of the triple protection design, the photoelectric encoder 6 brakes and stops when the depth value monitored in real time is zero; if there is an error or failure in the photoelectric encoder 6 for detecting the depth, the wellhead zero position detection device 7 makes a brake stop determination, and at the same time corrects the depth zeroing of the photoelectric encoder 6; a protection device 5 with an elastic function is installed at the blowout preventer wellhead 12. If both the photoelectric encoder 6 for detecting the depth and the wellhead zero position detection device 7 fail, the protection device 5 plays a role of anti-top buffering to prevent the downhole instrument from rushing out of the wellhead, and brakes and stops according to the maximum tension setting value of the tension sensor 4. It effectively prevents accidents of being pushed up and smashed down. Avoiding premature braking will cause the liquid in the pump to not be completely drained, affecting the pumping efficiency; late braking will cause the instrument to collide with the blowout preventer wellhead, resulting in damage to the blowout preventer wellhead or the instrument.

[0067] Further, such as Figure 1As shown in the figure, based on the above embodiments, an oil and gas well pumping wellhead protection system further includes a pulley block. The winch mechanism 1 is connected to the downhole instrument 8 through a cable steel 3 and the pulley block;

[0068] In the above embodiments, the crown block 10 provided directly above the blowout wellhead and the ground pulley 11 provided on the ground facilitate the sliding and turning of the steel cable 3.

[0069] In the present invention, as Figure 3 shown, it shows a module diagram of an oil and gas well pumping wellhead protection system of the present invention, which is used in the control system 2 and includes:

[0070] A first control module 201, which is used to control the control system 2 to control the downhole instrument 8 to rise at a constant speed, and to obtain the first information and the second information in real time. The first information is the depth value of the lifted downhole instrument 8 from a preset position of the wellhead, and the second information is the tension value of the steel cable of the lifted downhole instrument 8; and when the second information decreases and the first information decreases to within a preset numerical range, it switches to the second control module 202;

[0071] A second control module 202, which is used to control the control system 2 to control the downhole instrument 8 to decelerate and rise, and to obtain the third information in real time. The third information is the zero position signal of the lifted downhole instrument 8 from a preset position of the wellhead, and the depth zeroing signal of the control system 2 to control the photoelectric encoder 6; when the second information is greatly attenuated (liquid accumulation is discharged) and then decreases at a constant value, and the first information is zero, it is verified with the obtained third information and switches to the fourth control module 204; when the first information does not reach zero and the third information is obtained for verification and calibration, it switches to the fourth control module 204;

[0072] After the second information suddenly decreases and then decreases at a constant value, and the first information is zero and the third information is not obtained, it switches to the fourth module 204;

[0073] When the second information slowly increases, the first information does not reach zero, and the third information is not obtained, it switches to the third control module 203;

[0074] A third control module 203, which is used to control the control system 2 to control the downhole instrument 8 to pause and alarm. When the zero position signal acquisition fails, there is a large error in the depth signal, and the second information increases to a preset limit value, it controls the winch mechanism 1 to release the winch power and brake, and at the same time switches to the alarm module 205;

[0075] The fourth control module 204 is used to control the system 2 to pause the downhole instrument 8. When the third information is obtained, the power of the winch is released and the brake is applied, and the downhole instrument 8 pauses. When the first information is zero, it directly transfers to the fifth control module 206. When the first information does not reach zero, after adjusting the first information to zero, it transfers to the fifth module 206. If the error of the first information is greater than the preset value, the power of the winch is released and the brake is applied, and the downhole instrument 8 pauses, waiting for manual processing. When the third information is not obtained, the power of the winch is released and the brake is applied, and the downhole instrument 8 pauses, waiting for manual processing.

[0076] The fifth control module 206 controls the downhole instrument 8 to be lowered to a preset depth in the wellbore. When the downhole instrument 8 is lifted and rises at a constant speed, it transfers to step one.

[0077] The alarm module 205 receives the alarm signal from the third module and gives an alarm. When the error of the first information is greater than the preset value or the acquisition of the third information fails, it can also receive the alarm signal from the fourth module and give an alarm.

[0078] In the above embodiment, the downhole instrument 8 is hoisted through the steel cable 3. During the pumping operation, the first control module 201 of the control system 2 monitors the state of the downhole instrument 8 in the wellbore 9 in real time according to the two parameters of the measured tension value of the steel cable 3 and the measured depth value of the downhole instrument from the preset position of the wellhead. When the first information decreases and the second information decreases, that is, the downhole instrument 8 rises at a constant speed.

[0079] When the first information decreases to within the preset value range and the decreasing amplitude of the second information decreases, the second control module 202 controls the downhole instrument 8 to decelerate to the preset value in the wellbore and then rise at a constant speed, and obtains the third information in real time. When the second information suddenly decreases and then decreases at a constant value, and the first information is zero, when the third information is obtained, that is, the downhole instrument 8 enters the preset position of the wellhead, it transfers to the fourth control module.

[0080] When the second information suddenly decreases and then decreases at a constant value, and the first information does not reach zero, after obtaining the third information for verification and calibration, that is, the downhole instrument 8 enters the preset position of the wellhead, but there is a cumulative error in the process of lowering and lifting the downhole instrument 8, it transfers to the fourth control module 204.

[0081] When the second information slowly increases, the first information does not reach zero, and the third information is not obtained, that is, there is a cumulative error in the process of lowering and lifting the downhole instrument 8, and at the same time the zero position detection device fails, it transfers to the third control module 203.

[0082] The third control module 203 is used to control the system 2 to pause the downhole instrument 8 and give an alarm. When the zero position signal acquisition fails and the second information increases to the preset limit value, it controls the winch mechanism 1 to release the winch power and brake, and at the same time switches to the alarm module 205. That is, the downhole instrument 8 has risen to the preset zero position at the wellhead, and the photoelectric encoder 6 for zero position monitoring fails. At this time, the downhole instrument 8 is buffer-protected by the wellhead anti-top buffer protection device. When rising and encountering resistance, the speed of the steel cable being pulled up is slowed down, and the tension continues to increase. When the preset maximum tension value is reached, it controls the winch mechanism 1 to automatically release the winch power and brake, and at the same time issues an alarm output signal, and the downhole instrument 8 pauses, waiting for on-site staff to repair and handle. The alarm module 205 receives the alarm signal sent by the third control module 203 to remind the on-site staff to eliminate the fault.

[0083] The fourth control module 204 is used to control the system 2 to pause the downhole instrument 8. When the third information is obtained, the winch power is released and the brake is applied to make the downhole instrument 8 pause. When the first information does not obtain a zero value, after adjusting the first information to zero, it switches to the fifth module 206. That is, when the downhole instrument 8 enters the preset position at the wellhead, at this time, it controls the winch system 1 to release the winch power and brake, and the downhole instrument 8 pauses and the depth is reset to zero. When the third information is not obtained, the winch power is released and the brake is applied, and the downhole instrument 8 pauses, waiting for manual processing.

[0084] Furthermore, in the above embodiment, as Figure 1 shown, an oil and gas well swabbing wellhead protection system further includes: a control panel used in the control system 2, and the display, operation buttons, and signal lights on the control panel are electrically connected to the corresponding control modules in the control system 2; so that the depth and tension parameters obtained by the control system 2 in real time are displayed on the display of the control panel, and on-site staff can clearly and intuitively judge the position and state of the downhole instrument 8 in the wellbore 9.

[0085] Exemplarily, the control panel is a liquid crystal touch screen display, which includes a tension display, a depth display, a zero position signal display, a warning light, a voice alarm, as well as constant tension operation, constant speed operation, remote control buttons, and a wireless control handle; the control panel is electrically connected to the modules in the control system 2, the winch motor, the winch brake, and the power switch through a collection line, a control line, or a wireless transceiver device respectively; the warning light is electrically connected to the alarm module 205; the tension display is electrically connected to the first control module 201, the second control module 202, and the third control module 203 through a control pipeline respectively; the depth display is connected to the photoelectric encoder 6 through a collection line. At the same time, the control panel is electrically connected to the first control module 201, the second control module 202, and the fourth control module through a control pipeline respectively. The photoelectric encoder 6 is installed on the rotating shaft of the winch drum, and converts the mechanical geometric displacement on the output shaft into pulses or digital quantities through photoelectric conversion. The real-time depth value is displayed through the winch panel. In the present invention, an encoder of Martindale can also be used to measure the depth;

[0086] The zero position detection device 7 transmits signals into the second control module 202, the fourth control module 204, and the third control module 203 in the control system 2 through a cable or a wireless transmitter; the zero position detection device 7 is electrically connected to the zero position signal display on the control panel; the third control module 203 and the fourth control module 204 in the control system 2 are electrically connected to the motor and the brake in the winch mechanism 1.

[0087] In the present invention, as Figure 5 shown, it shows a structural diagram of the protection device 5 in an oil / gas well pumping wellhead protection system of the present invention, including: an upper housing 501 and a lower housing 502 with one end open. The upper housing 501 and the lower housing 502 are slidably sleeved to form a closed accommodation cavity, and a spring 503 is arranged in the accommodation cavity; central holes are opened at the blind ends of the upper housing 501 and the lower housing 502 for the steel cable 3 to pass through. Exemplarily, the open end of the upper housing 501 and the open end of the lower housing 502 are clamped by a limiting platform, and the inner wall of the upper housing 501 and the outer wall of the lower housing 502 are in clearance fit to achieve sliding sleeving.

[0088] In the above embodiments, the protection device 5 plays a role of buffering and protecting the downhole instrument 8; when the zero-position sensor 7 in the wellbore 9 fails, the control system 2 does not receive the zero-position signal when the downhole instrument 8 passes through the preset position at the wellhead; at this time, the upper end of the downhole instrument 8 abuts against the lower end of the lower housing 502 of the protection device 5, the protection device 5 is squeezed and compressed, the downhole instrument 8 is blocked, the speed of the steel cable 3 being pulled up is slowed down, and at this time, the tension of the steel cable continuously increases until it reaches the preset maximum tension (the maximum tension value that can be borne plus the safety factor), the control system 2 automatically releases the power of the winch and brakes, and issues an alarm to prompt the on-site personnel for maintenance. The protection device 5 plays a buffering role, slows down the speed of the downhole instrument 8 being pulled up, decelerates until the equipment stops, ensures safety, and at the same time avoids the high-speed impact of the steel cable driving the downhole instrument against the blowout preventer wellhead.

[0089] In the present invention, as Figure 6 shown, it shows a structural diagram of the zero-position detection device 7 in an oil / gas well pumping wellhead protection system of the present invention, including: a winding body 701 having a through hole, an induction coil 702 wound on the winding body 701, and opposite-polarity magnets 703 provided at both ends of the winding body 701, capable of generating a constant magnetic field; an amplifier 704 (i.e., an amplification and filtering circuit board) is further provided at one end of the winding body 701 and is located outside the magnet 703; further, an outer casing is sleeved outside the winding body 701. It should be noted that the through hole of the winding body 701, the through hole of the magnet 703, and the through hole of the amplifier 704 are in communication with each other to form a central through hole 705 of the zero-position detection device 7.

[0090] In the above embodiments, the zero-position detection device 7 is mainly used to detect the depth of the up-and-down movement of the downhole instrument 8 and provide a signal basis for wellhead braking; at the same time, it can correct the depth of each steel cable 3 being lowered to eliminate the errors affecting the depth caused by cumulative and data loss. When the downhole instrument 8 moves in the central through hole 705 of the zero-position detection device 7, it causes a change in the magnetic flux of the zero-position detection device 7, generates an induced current, and after the induced current is amplified, rectified, and converted by the amplifier 704, the zero-position signal is transmitted to the control system 2 to control the depth of the winch mechanism 1 to return to zero and the stop action.

[0091] For those skilled in the art, it is obvious that the above specific factual examples are only the preferred solutions of the present invention. Therefore, the improvements and changes that some parts of the present invention may make by those skilled in the art still reflect the principle of the present invention and achieve the purpose of the present invention, and all belong to the scope protected by the present invention.

Claims

1. A method for protecting a pumping wellhead of an oil / gas well, characterized in that, It includes the following steps: Step 1: Control the downhole instrument (8) to rise at a constant speed and obtain the first information and the second information in real time. When the first information decreases and the second information decreases gradually until the first information decreases to the preset value range, go to Step 2. In Step 1, the first information is the depth value of the hoisted downhole instrument (8) from the preset position at the wellhead, and the second information is the tension value of the steel cable of the hoisted downhole instrument (8). Step 2: Control the downhole instrument (8) to decelerate to the preset speed, rise at a constant speed, and obtain the third information in real time. When the second information decreases suddenly and then decreases at a constant value, and the first information is zero, verify with the obtained third information and go to Step 4. When the first information does not reach zero and the third information is obtained for calibration, go to Step 4. In Step 2, the third information is the zero position signal at the preset position at the wellhead and the zeroing signal for controlling the calibration of the first information. After the second information decreases suddenly and then decreases at a constant value, and the first information is zero, if the third information is not obtained, go to Step 4. If the second information increases slowly, the first information does not reach zero, and the third information is not obtained, go to Step 3. Step 3: Start the anti-top buffer protection at the wellhead. When the second information increases to the preset limit value, give an alarm and go to Step 4 at the same time. Step 4: When the third information is obtained, release the power of the winch and apply the brake. The downhole instrument (8) pauses. When the first information is zero, directly go to Step 5. When the first information does not reach zero, adjust the first information to zero and then go to Step 5. When the third information is not obtained, release the power of the winch and apply the brake. The downhole instrument (8) pauses and waits for manual processing. Step 5: Control the downhole instrument (8) to lower to the preset depth, and then re-hoist and go to Step 1.

2. The oil / gas well pumping wellhead protection method according to claim 1, wherein In Step 4, when the third information is obtained and the first information does not reach zero, if the error of the first information is greater than the preset value, release the power of the winch and apply the brake. The downhole instrument (8) pauses and waits for manual processing.

3. An oil / gas well swabbing wellhead protection system, characterized in that, It includes a control system (2), a winch mechanism (1), a steel cable (3), a tension sensor (4), an optical encoder (6), a zero position detection device (7), a pulley block, and a protection device (5) for anti-top buffer. The winch mechanism (1) is connected to the downhole instrument (8) through the steel cable (3). The tension sensor (4) is arranged on the load-bearing rope of the crown block (10) in the pulley block. The optical encoder (6) is installed on the rotating shaft of the drum of the winch mechanism (1). The zero position detection device (7) is installed at the preset position of the blowout preventer wellhead (12). The protection device (5) is installed on the top of the blowout preventer wellhead (12). The control system (2) is respectively connected to the tension sensor (4), the optical encoder (6), and the zero position detection device (7) by signals. The control system (2) is electrically connected to the motor and the brake of the winch mechanism (1). The zero position detection device (7) includes a winding body (701) around which an induction coil (702) is wound, and magnets (703) with the same polarity facing each other are arranged at both ends of the winding body (701); an amplifier (704) is also arranged at one end of the winding body (701), and the amplifier (704) is electrically connected to the control system (2) by an electrical signal; The protection device (5) includes an upper shell (501) and a lower shell (502) with one end open. The upper shell (501) and the lower shell (502) are slidably sleeved to form a closed accommodation cavity, and a spring (503) is arranged in the accommodation cavity; In the control system (2), it includes: a first control module (201) that controls the downhole instrument (8) to rise at a constant speed, and obtains the first information and the second information in real time. When the second information decreases and the first information decreases to a preset value range, it switches to the second control module (202); The second control module (202) controls the downhole instrument (8) to decelerate to a preset speed and rise at a constant speed, and obtains the third information in real time. When the second information suddenly decreases and then decreases at a constant value, and the first information is zero, it is verified with the obtained third information and switches to the fourth control module (204); When the first information does not reach zero, the obtained third information is verified and calibrated, and it switches to the fourth control module (204); When the second information suddenly decreases and then decreases at a constant value, and the first information is zero, but the third information is not obtained, it switches to the fourth control module (204); When the second information slowly increases, the first information does not reach zero, and the third information is not obtained, it switches to the third control module (203); The third control module (203), when the third information acquisition fails and the second information increases to a preset limit value, releases the power of the winch and brakes, and at the same time switches to the alarm module (205); The fourth control module (204), when the third information is obtained, releases the power of the winch and brakes, the downhole instrument (8) pauses. When the first information is zero, it directly switches to the fifth control module (206). When the first information does not reach zero and the error is less than the preset value, after adjusting the first information to zero, it switches to the fifth control module (206). If the error of the first information is greater than the preset value, the power of the winch is released and the brakes are applied, the downhole instrument (8) pauses, and waits for manual processing; When the third information is not obtained, the power of the winch is released and the brakes are applied, the downhole instrument (8) pauses, and waits for manual processing; The fifth control module (206) controls the downhole instrument (8) to be lowered to a preset depth in the wellbore, and when the downhole instrument (8) is lifted, it switches to step one; In the control system (2), it includes: a control panel in the control system (2), and the control panel is electrically connected to the control module in the control system (2); The control panel is electrically connected to the motor and the brake in the winch mechanism (1).

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