Liquid level identification, liquid discharge volume metering system and well clearing method based on wire-tight liquid discharge

Abstract

The present invention relates to a liquid level recognition and liquid discharge volume metering system based on steel wire closed liquid discharge and a well clearing method. The well clearing method collects liquid bailing data in a liquid bailing process in real time, and plays back the liquid bailing data acquired in the liquid bailing process after a liquid bailing is completed. The liquid bailing data is reorganized and processed by a host computer, and a data curve is drawn. The liquid bailing volume, liquid level depth before liquid bailing and liquid bailing leakage rate are calculated according to the data curve, and a reference depth is provided for the next liquid bailing operation, thereby solving the problem of large deviation in artificial judgment of liquid bailing depth and liquid bailing volume, realizing digital and intelligent management of the liquid bailing process, and improving the efficiency of steel wire closed liquid discharge operation.

Description

Technical Field

[0001] The invention belongs to the technical field of gas well drainage and gas production, and particularly relates to a liquid level identification and drainage volume metering system based on steel wire closed drainage and a well clearing method. Background Art

[0002] As the exploitation of gas wells in my country continues to deepen, the pressure of gas wells continues to decrease, and the water and liquid content in the gas reservoir continues to increase, which cannot flow out of the wellbore with the gas flow. This will accumulate in the wellbore to form a liquid column, which will cause additional hydrostatic back pressure on the gas reservoir and cause the gas well's self-flowing capacity to continue to decline. If the gas well continues to accumulate liquid, the liquid column accumulated in the wellbore will crush the gas well and cause the gas well to stop production. Therefore, fast and effective gas well drainage and gas production technology is the key to maintaining gas well productivity.

[0003] At present, the commonly used drainage and gas production technologies include foam drainage and gas production, gas lift drainage and gas production, plunger gas lift drainage and gas production, mechanical drainage and gas production, liquid nitrogen drainage and gas production, and jet gas lift drainage and gas production. Among them, the steel wire closed drainage process used in mechanical drainage and gas production is a newly developed technology, which can realize the measurement of the steel wire depth and tension measurement of the liquid bailing and pumping device. The original steel wire closed drainage process is to lower the liquid bailing and pumping device by lifting the steel wire closed drainage vehicle. At the same time, the operator observes the tension meter on the steel wire closed drainage vehicle to determine the liquid level in the well, and then lowers the liquid bailing and pumping device to a certain depth according to the steel wire depth meter, and then performs the liquid lifting operation. The lifting of the liquid bailing and pumping device causes the space in the oil pipe located at the upper part of the pumping to be squeezed, resulting in an increase in the pressure of the barometer. When a certain pressure threshold is reached, it is necessary to open the needle valve and continue to pull the steel wire to pull the liquid bailing and pumping device, driving the liquid on the upper part of the oil pipe to discharge from the wellbore to achieve the purpose of drainage.

[0004] This process requires manual judgment of the depth and amount of liquid salvage through a steel wire depth meter and a tension meter, and is unable to monitor the dynamic liquid level and downhole temperature and pressure. In addition, due to the complex downhole environment and the well depth often exceeding 2 km, the steel wire depth meter and the tension meter cannot accurately reflect the actual changes in the liquid salvage pumping device in the flooded gas well. It is very difficult to manually determine the wellhead discharge height based on the steel wire depth and steel wire tension, and requires high experience from the operator. Inaccurate judgment of the liquid level often occurs, and multiple operations are required. However, errors in judging the liquid level will result in empty salvage or overload of the liquid salvage pumping device, and automatic liquid level recognition and discharge volume measurement cannot be achieved. Not only is the efficiency of the liquid salvage operation low, but it also increases the workload of the operator. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to propose a liquid level recognition, discharge volume metering system and well clearing method based on wire-sealed drainage, which calculates the liquid volume and liquid level depth before liquid dredging by collecting liquid dredging data in real time during the dredging process and combining the downhole temperature, pressure and other data collected during the dredging process after the end of one dredging. This solves the problem of large deviations in artificial judgment of liquid dredging depth and liquid volume.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A liquid level identification and liquid discharge volume metering system based on wire-sealed liquid discharge, comprising a wire-sealed liquid discharge vehicle, a liquid bailing and pumping device, a gas production tree and a metering device, wherein the lower end of the gas production tree is connected to an oil pipe, the wire-sealed liquid discharge vehicle suspends the liquid bailing and pumping device and lowers it into the oil pipe, the metering device comprises an upper computer, an oil pressure transmitter, a casing pressure transmitter, a wire metering module and a downhole temperature and pressure meter, the oil pressure transmitter and the casing pressure transmitter are respectively arranged on the gas production tree for collecting wellhead oil pipe pressure data and wellhead The casing pressure data of the oil pipe, the steel wire metering module is connected to the steel wire closed liquid discharge vehicle to collect the steel wire tension data and the steel wire lowering depth data, a pair of the downhole temperature and pressure gauges are respectively arranged at the upper and lower ends of the liquid bailing and pumping device and are carried into the oil pipe by the liquid bailing and pumping device to collect the downhole temperature and pressure data, the upper computer is wirelessly connected with the oil pressure transmitter, casing pressure transmitter, steel wire metering module and downhole temperature and pressure gauge to receive the collected liquid bailing data and then measure the liquid level depth and discharge volume in the well.

[0008] Furthermore, the metering device also includes a ground controller and a wellhead wireless communication module. The wellhead wireless communication module is arranged at the upper end of the gas production tree and is used to wirelessly transmit the liquid salvage data to the ground controller. The ground controller is used to wirelessly send the liquid salvage data to the host computer.

[0009] The present invention also provides a well cleaning method based on steel wire sealed liquid drainage, using the liquid level identification and liquid drainage volume metering system based on steel wire sealed liquid drainage of the present invention, the well cleaning method comprises the following steps:

[0010] Step S1, the metering device collects the liquid scooping data of the liquid scooping process in real time, and transmits the liquid scooping data to the host computer wirelessly after the liquid scooping is completed;

[0011] Step S2, the upper computer plots the liquid bailing data into a data curve, wherein the data curve includes a steel wire tension data curve, a steel wire lowering depth data curve, a wellhead tubing pressure data curve, a wellhead tubing casing pressure data curve, a downhole temperature data curve, a pumping upper pressure data curve, and a pumping lower pressure data curve;

[0012] Step S3: the upper computer calculates the upper pumping pressure F according to the upper pumping pressure data curve. up (t), pumping pressure F of the pumping pressure data curve down (t) and the wellhead tubing pressure data curve of the wellhead tubing pressure F o Determine the starting needle valve closing point t0;

[0013] Step S4, starting from the needle valve closing point t0, the host computer analyzes the upper pumping pressure data curve, the lower pumping pressure data curve and the steel wire lowering depth data curve to determine the time point when the liquid scooping pumping device contacts the liquid surface, and obtains the steel wire depth when the liquid scooping pumping device contacts the liquid surface according to the time point when the liquid scooping pumping device contacts the liquid surface, and takes the steel wire depth when the liquid scooping pumping device contacts the liquid surface as the liquid surface depth h liq ;

[0014] If the host computer cannot determine the time point when the liquid scooping and pumping device touches the liquid surface, it is determined that no liquid is scooped this time;

[0015] Step S5: The host computer traverses the entire wire lowering depth data curve to determine the wire pulling time point, and uses the wire depth at the wire pulling time point as the wire scooping depth to calculate the current scooping height h. get ;

[0016] Step S6: The host computer traverses the entire pumping pressure data curve to determine the time point when the drain needle valve is opened, and the wire depth at the time point when the drain needle valve is opened is used as the pumping depth h at the needle valve opening point. open ;

[0017] Step S7, the host computer traverses the entire wellhead oil pipe pressure data curve to determine the needle valve closing point, and uses the wire depth at the needle valve closing point as the pumping depth h at the needle valve closing point. close ,but:

[0018] Wellhead drainage height h d = Pumping depth h at the needle valve opening point open - Suction depth h at needle valve closing point close ;

[0019] Step S8: The host computer calculates the wellhead discharge height h d Calculate the volume V of this discharge:

[0020]

[0021] Where D is the inner diameter of the oil pipe;

[0022] The upper computer determines the liquid height h get and wellhead discharge height h d Calculate the pumping loss Δh LR and the leakage rate η LR :

[0023] Δh LR =h get -h d ;

[0024]

[0025] Step S9: The host computer determines the wellhead discharge height h d , liquid level depth h liq Calculate and predict the next liquid level depth

[0026]

[0027] Step S10, the upper computer determines whether the well is ventilated according to the gas well pressure, and if the well is ventilated, the liquid bailing operation is terminated;

[0028] If the well is not connected, the next liquid level depth is predicted. Repeat steps S1-S10 to lower the liquid bailing pumping device again to perform liquid bailing operations until the well is unblocked.

[0029] Further, in step S3, the starting needle valve closing point t0 is determined by: increasing the pumping pressure F up (t), pumping pressure F down (t) and wellhead tubing pressure F o Satisfy: |F up (t)-F o (t)|<Δf close And |F down (t)-F o (t)|<Δf close The time change point is taken as the starting needle valve closing point t0; Δf close The pumping pressure F up (t), pumping pressure F down (t) and the wellhead tubing pressure F. Difference threshold.

[0030] Furthermore, the host computer analyzes the upper pressure data curve, the lower pressure data curve and the steel wire lowering depth data curve, specifically including: calculating the time point t a-1+i and time point t i-1 The upper pressure or lower pressure of the pumping during the pumping process changes with the depth of the steel wire lowering h. (t) Gradient of change ΔF: Where: a is the number of points in the sliding window, i is the number of window sliding times, a and i are natural numbers; t a-1+i is the a-th point of the i-th sliding window, t i-1 is the first point of the i-th sliding window, F a-1+iis time point t a-1+i The pressure at the time, F i-1 is time point t i-1 The pressure at time, h a-1+i is time point t a-1+i Wire depth at time, h i-1 is time point t i-1 When the gradient ΔF is negative or lower than the threshold Δf liq When the gradient ΔF is greater than the threshold Δf liq When the liquid is sucked out, make sure that the liquid suction device reaches the liquid surface.

[0031] Furthermore, the gradient ΔF includes the gradient ΔF of the pumping pressure. down and the pressure gradient ΔF on the pump up ; If the pressure gradient ΔF down First greater than the threshold Δf liq When the liquid scooping device reaches the liquid surface, the time point t a+y-1 As the inflection point of the pumping pressure, y is the number of sliding times of the pumping pressure judgment window; if the gradient of the pumping pressure ΔF up After it is greater than the threshold Δf liq At this time, the time point t a+z-1 As the inflection point of the upper pumping pressure, z is the sliding number of the upper pumping pressure judgment window, and y and z are natural numbers.

[0032] Furthermore, the host computer analyzes the upper pressure data curve, the lower pressure data curve and the steel wire lowering depth data curve, and also includes:

[0033] The upper computer fits the upper pumping pressure at the inflection point of the lower pumping pressure and the lower pumping pressure at the inflection point of the upper pumping pressure to determine whether the slope of the upper pumping pressure and the lower pumping pressure variation function is positive and the slope difference is less than a threshold value Δk;

[0034] The upper computer calculates the wire tension data curve of the wire tension before and after the upper pressure inflection point and the lower pressure inflection point of the pumping, and the wire tension change ΔF s , determine whether |ΔF is satisfied s |>Δf s , Δf s is the wire tension change threshold;

[0035] If both conditions are met, then the wire depth h of the pressure inflection point under pumping is a+y-1 As the liquid depth h liq ;

[0036] If it is not satisfied, the window will continue to slide to find the upper pressure inflection point and the lower pressure inflection point of the pumping. If the window slides to the end and is not satisfied, it is determined that no liquid is collected this time.

[0037] Further, in step 5, the host computer traverses the entire wire lowering depth data curve to determine the wire pulling time point, and uses the wire depth at the wire pulling time point as the wire scooping depth, and calculates the current scooping height h get Specifically, the host computer traverses the entire wire lowering depth data curve, and takes the time point corresponding to the maximum wire lowering depth as the time point t at which the wire is lowered to the longest position. max , calculate the change in wire length Δh1 of the adjacent points from this position, then: Δh1=h x+1 -h x ;

[0038] Among them, x is the time from the time point t max The starting point is x, which is a natural number, h x From time point t max The starting point x is the wire depth at this time, h x+1 is the wire depth of the next point of point x;

[0039] When Δh1<-1m, 10 points are taken as the sliding window starting from point x, each sliding step is one point, and the depth of the 10th point is taken as h 9+k+x , the depth of the first point is h k-1+x , k is the number of sliding windows, k is a natural number, then: Δh 10 =h 9+k+x -h k-1+x ;

[0040] Where Δh 10 It represents the difference between the wire depth at the 10th point and the 1st point in the sliding window. If Δh 10 When <-10m, determine t k-1+x Point is the point where the wire is pulled up, and the length of the wire at this time is recorded. k-1+x As the depth of the wire pull-up point, the height of the liquid scoop h get , then: h get =h k-1+x -h liq .

[0041] Furthermore, the host computer traverses the entire pumping pressure data curve to determine the opening time of the drain needle valve, and the wire depth at the opening time of the drain needle valve is used as the pumping depth h at the needle valve opening point. open , specifically including:

[0042] Step S61: The host computer traverses the entire downhole pressure data curve and takes the maximum value point position t upmaxAs the starting point p of the analysis, c points are taken from this point as the sliding window, each sliding step is one point, and the pressure of the cth point is taken as F c-1+i+p , the pressure at the first point is F i-1+p , calculate the pressure change ΔF c , i is the number of window sliding times, c and i are natural numbers, then: ΔF c =F c-1+i+p -F i-1+p ;

[0043] Step S62, determine whether ΔF is satisfied c <-Δf c , Δf c is the threshold; if not satisfied, execute step S63; if satisfied, execute step S64;

[0044] Step S63, continue sliding the window to find the point;

[0045] Step S64, the wire tension F s Make a judgment and take the tension at point c as F sc-1+i+p , the pressure at the first point is F si-1+p , calculate the tension change ΔF s , then: ΔF s =F sc-1+i+p -F si-1+p ;

[0046] Step S65, determine whether ΔF is satisfied s <-Δf s , Δf sc is the threshold value;

[0047] If not, execute step S67; if satisfied, execute step S66;

[0048] Step S66, then time point t i-1+p Point is the needle valve opening point t op , the length of the steel wire at this time is h i-1+p As the needle valve opens the pumping depth h open ;

[0049] Step S67, return to step S63.

[0050] Further, in step 7, the host computer traverses the entire pumping pressure data curve to determine the opening time point of the drainage needle valve, specifically: the host computer queries the wellhead tubing pressure data F from the needle valve opening point backward. The sliding window finds the maximum value F omax and the minimum value F omin , then F omax and F omin The difference ΔF o =ΔF o=F omax -F omin ;

[0051] Determine whether the following conditions are met at the same time: ΔF o <Δf o and F omax <f oc , Δf o is the threshold; if not satisfied, the sliding window continues; if satisfied at the same time, the m-1th point at this time is used as the needle valve closing point, m is the number of window sliding times, and m is a natural number.

[0052] The present invention adopts the above technical solution, which has the following advantages and effects:

[0053] (1) The present invention provides a liquid level recognition and liquid discharge volume metering system and a well clearing method based on wire-sealed liquid discharge. The downhole temperature and pressure meter collects the downhole pressure change of the liquid bailing and pumping device. The wire metering module collects the wire depth and tension metering data of the wire-sealed liquid discharge vehicle. The ground controller obtains the collected data through wireless communication, summarizes and uploads it to the host computer. The host computer calculates the current liquid bailing volume through liquid level recognition and liquid discharge volume metering algorithm, and calculates the predicted liquid level depth of the next liquid bailing through the recognized liquid level depth and wellhead liquid discharge height, providing a reference for the next liquid bailing operation. When the next liquid bailing operation is performed, it is only necessary to lower the liquid bailing and pumping device to the predicted current wellhead liquid discharge height, and then carry out the subsequent liquid bailing process. There is no need to manually determine the wellhead liquid discharge height, thereby solving the problem of large deviations in manual judgment of liquid bailing depth and liquid bailing volume.

[0054] (2) The present invention provides a liquid level recognition and liquid discharge volume metering system and a well clearing method based on closed liquid discharge by steel wire. The liquid level position in the wellbore is determined by measuring the change in the tension of the steel wire. After a liquid bailing operation is performed, the upper computer can calculate the liquid discharge volume and predict the current wellhead discharge height based on the playback data. There is no need to enter the site for multiple liquid bailing operations, thus reducing the labor intensity of personnel. At the same time, the liquid bailing volume and the leakage volume in each liquid bailing process are calculated to obtain the liquid bailing efficiency and evaluate the sealing quality of the liquid bailing pumping device. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a structural schematic diagram of the liquid level recognition and liquid discharge volume metering system based on steel wire sealed liquid discharge of the present invention.

[0056] Figure 2 The present invention is a process flow chart of the liquid level identification and liquid discharge volume metering system based on the steel wire closed liquid discharge.

[0057] Figure 3 The present invention is a flow chart of a well clearing method for liquid level recognition and liquid discharge volume measurement based on wire-tight liquid discharge.

[0058] Figure 4 This is a data curve diagram of the well cleaning method of the present invention after one liquid bailing.

[0059] Figure 5 The present invention is a flow chart of a liquid level recognition algorithm for a well clearing method based on closed wire drainage.

[0060] Figure 6 The present invention is a flow chart of the algorithm for the drainage volume of the well clearing method based on the steel wire closed drainage.

[0061] The accompanying drawings are marked as follows: 1-host computer; 2-ground controller; 3-wellhead wireless communication module; 4-oil pressure transmitter; 5-casing pressure transmitter; 6-wire metering module, 7-downhole temperature and pressure meter; 8-wire closed liquid discharge vehicle; 9-liquid bailing and pumping device; 10-oil pipe; 11-needle valve; 12-gas tree; 13-barometer. DETAILED DESCRIPTION

[0062] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0063] like Figure 1-Figure 2 The present invention provides a liquid level identification and liquid discharge volume metering system based on wire-sealed liquid discharge, comprising a wire-sealed liquid discharge vehicle 8, a liquid bailing and pumping device 9, a gas tree 12 and a metering device, wherein a pressure gauge 13 is arranged on the gas tree 12, and an oil pipe 10 is connected to the lower end of the gas tree 12, and the oil pipe 10 is lowered into the formation, and the liquid bailing and pumping device 9 can be suspended and lowered into the oil pipe 10 through the wire-sealed liquid discharge vehicle 8. The metering device includes a host computer 1, an oil pressure transmitter 4, a casing pressure transmitter 5, a steel wire metering module 6 and a downhole temperature and pressure meter 7. The oil pressure transmitter 4 and the casing pressure transmitter 5 are respectively arranged on the gas tree 12. The oil pressure transmitter 4 is connected to the gas tree 12 for collecting the tubing pressure. The casing pressure transmitter 5 is connected to the gas tree 12 for collecting the tubing casing pressure. The steel wire metering module 6 is connected to the steel wire of the steel wire closed liquid discharge vehicle 8 for collecting the steel wire hoisting tension and lowering depth. A pair of downhole temperature and pressure meters 7 are respectively arranged at the upper and lower ends of the liquid bailing and pumping device 9 and are carried by the liquid bailing and pumping device 9 into the oil pipe 10 for collecting the downhole temperature and pressure data of the upper and lower parts of the liquid bailing and pumping device 9. The host computer 1 is wirelessly connected to the oil pressure transmitter 4, the casing pressure transmitter 5, the steel wire metering module 6 and the downhole temperature and pressure meter 7 for receiving the collected liquid bailing data and then calculating the actual liquid level depth and the amount of liquid discharged each time. Wellhead tubing pressure data, wellhead tubing casing pressure data, wire tension data, wire lowering depth data and downhole temperature and pressure data are used as the liquid salvage data.

[0064] Furthermore, the metering device also includes a ground controller 2 and a wellhead wireless communication module 3. The wellhead wireless communication module 3 is arranged at the upper end of the gas production tree 12 and is used to wirelessly transmit the liquid salvage data to the ground controller 2. The ground controller 2 is used to send the liquid salvage data to the host computer 1. After analyzing the liquid salvage data, the host computer 1 runs the liquid level recognition algorithm and the liquid discharge algorithm to calculate the actual liquid level depth and the liquid discharge volume each time in the well.

[0065] Specifically, the upper end of the gas production tree 12 is connected to the wellhead wireless communication module 3 through the needle valve 11, and the ground controller 2 obtains the liquid bailing data collected by the steel wire metering module 6, the oil pressure transmitter 4, and the casing pressure transmitter 5 through wireless communication. When the liquid bailing pumping device 9 discharges the liquid out of the well, the downhole temperature and pressure instrument 7 communicates with the wellhead wireless communication module 3 wirelessly, and sends the temperature and pressure data collected downhole to the ground controller 2. The ground controller 2 collects the data collected by each device and sends it to the host computer 1. The host computer 1 analyzes the liquid bailing data, and then runs the surface recognition algorithm and the liquid discharge algorithm to obtain the actual liquid level depth and each discharge volume of the downhole. The steel wire closed liquid discharge vehicle 8 hoists the liquid bailing pumping device 9 and enters the oil pipe 10 after opening the needle valve 11. After the needle valve 11 is closed, the liquid bailing pumping device 9 performs closed liquid discharge in the oil pipe 10.

[0066] The liquid level recognition and liquid discharge volume metering system based on the closed wire drainage of the present invention can use the liquid level recognition algorithm and the liquid discharge volume algorithm. When going down the well for the first time, the closed wire drainage vehicle 8 measures the change of the wire tension to determine the position of the liquid level in the wellbore. After a liquid bailing operation, the upper computer 1 uses the liquid level recognition algorithm and the liquid discharge algorithm to calculate the liquid discharge volume and the predicted current wellhead liquid discharge height according to the playback data. When the liquid is bailed out next time, the liquid bailing pumping device 9 is lowered to predict the current wellhead liquid discharge height, and the subsequent liquid bailing process is carried out, without the need to manually judge the wire tension to determine the wellhead liquid discharge height.

[0067] like Figure 3 The present invention provides a well cleaning method based on steel wire sealed liquid drainage, which is applied in the liquid level identification and liquid drainage volume metering system based on steel wire sealed liquid drainage of the present invention. The well cleaning method includes the following steps:

[0068] Step S1, during the downhole process, the oil pressure transmitter 4, casing pressure transmitter 5, wire metering module 6 and downhole temperature and pressure meter 7 of the metering device collect the liquid bailing data of the liquid bailing process in real time. The liquid bailing data includes wire tension, wire lowering depth, oil pressure and casing pressure data. After a liquid bailing is completed, the liquid bailing data is wirelessly transmitted to the upper computer 1 of the metering device.

[0069] Specifically, the closed wire drainage vehicle 8 suspends the liquid scooping device 9 and the downhole temperature and pressure instrument 7 of the metering device and goes down the well. The oil pressure transmitter 4 of the metering device collects oil pressure data in real time, the casing pressure transmitter 5 collects casing pressure data in real time, the wire metering module 6 collects wire tension data and wire lowering depth data in real time, and the downhole temperature and pressure instrument 7 collects downhole temperature data, pumping upper pressure data and pumping lower pressure data in real time. After a scooping is completed, the downhole temperature and pressure instrument 7 communicates wirelessly with the wellhead wireless communication module 3, and sends the collected downhole temperature data, pumping upper pressure data and pumping lower pressure data to the wellhead wireless communication module 3, and the wellhead wireless communication module 3 then sends the data to the ground controller 2 through wireless communication. The oil pressure transmitter 4, the casing pressure transmitter 5 and the wire metering module 6 simultaneously wirelessly send the collected oil pressure data, casing pressure data, wire tension data and wire lowering depth data to the ground controller 2, and the ground controller 2 summarizes the scooping data and sends it to the host computer 1.

[0070] Step S2, the upper computer 1 of the metering device plots the liquid scooping data into a data curve with the time point sequence as the horizontal axis and the liquid scooping data at the corresponding time as the vertical axis.

[0071] Specifically, the upper computer 1 of the metering device reorganizes, processes and stores the liquid scooping data in a database according to the recording time of the time point, and draws a data curve in the order of the time points of the liquid scooping process and displays the liquid scooping data in the form of a curve.

[0072] like Figure 4 As shown. When drawing the data curve, according to different liquid salvaging data, the data curve includes the upper pressure data curve E of the pumping, the lower pressure data curve D of the pumping, the temperature data curve of the pumping, the steel wire lowering depth data curve B, the steel wire tension data curve C, the wellhead tubing pressure data curve A and the wellhead casing pressure data curve. Each data curve is drawn with the time point of data collection as the horizontal coordinate and the corresponding liquid salvaging data value collected as the vertical coordinate. Among them, the pumping temperature data curve is drawn according to the downhole temperature data, the upper pressure data curve of the pumping is drawn according to the upper pressure data of the pumping, the lower pressure data curve of the pumping is drawn according to the lower pressure data of the pumping, the steel wire lowering depth data curve is drawn according to the steel wire lowering depth data, the steel wire tension data curve is drawn according to the steel wire tension data, the wellhead tubing pressure data curve is drawn according to the wellhead tubing pressure data, and the wellhead tubing pressure data curve is drawn according to the wellhead casing pressure data.

[0073] Step S3, the upper computer 1 of the metering device calculates the upper pumping pressure F according to the upper pumping pressure data curve E. up (t), the pumping pressure F of the pumping pressure data curve D down (t) and the wellhead tubing pressure data curve A of the wellhead tubing pressure F oThe starting needle valve closing point t0 is determined and taken as the starting point for data analysis.

[0074] Specifically, the upper computer 1 pumps the pressure F up (t) and the pumping pressure F down (t) changes from 0 to the wellhead tubing pressure F o The difference is at the threshold Δf close The time change point within the range is taken as the starting needle valve closing point t0 after pumping and lowering the oil pipe, which satisfies:

[0075]

[0076] (1) In the formula, the threshold Δf close It is the threshold value of the difference between the upper pressure or the lower pressure and the wellhead tubing pressure. close The threshold Δf is determined based on the wellhead tubing pressure at the site and the upper and lower pumping pressures after the needle valve is closed. close , threshold Δf close Can be modified.

[0077] Step S4, starting from the needle valve closing point t0, the upper computer 1 runs the liquid level recognition algorithm to analyze the liquid scooping data on the upper pumping pressure data curve E, the lower pumping pressure data curve C and the steel wire lowering depth data curve A to determine the time point when the liquid scooping pumping device 9 contacts the liquid surface, thereby obtaining the steel wire depth when the liquid scooping pumping device 9 contacts the liquid surface, and the steel wire depth when the liquid scooping pumping device 9 contacts the liquid surface is used as the liquid surface depth h liq ;

[0078] If the liquid level recognition algorithm cannot determine the time point when the liquid scooping and pumping device 9 contacts the liquid surface after analyzing the entire data curve, it is determined that no liquid is scooped this time, and the data curve analysis is terminated.

[0079] like Figure 5 Specifically, the liquid level recognition algorithm includes: starting from the needle valve closing point t0, the wire lowering depth h (t) When it is increasing, it is determined to be the steel wire lowering process. For the time point, a points are used as the sliding window. a is preferably a natural number between 10 and 20. Each sliding step is one point. The time points t a-1+i and time point t i-1 The upper pressure or lower pressure between the two changes with the depth of the steel wire lowering h. (t) The gradient of the change ΔF. i is the number of window sliding times, i is preferably a natural number between 100-200, t a-1+i is the a-th point of the i-th sliding window, t i -1 is the first point of the i-th sliding window, then:

[0080]

[0081] (2) In the formula, F a-1+i is time point t a-1+i Pressure at point, F i-1 is time point t i-1 Pressure at point, h a-1+i is time point t a-1+i Wire depth at point, h i-1 is time point t i-1 The wire depth of the point; when the gradient ΔF is negative or below the threshold Δf liq When the liquid scooping device 9 is judged to have not reached the liquid surface, the threshold Δf liq is the judgment threshold of gradient ΔF.

[0082] When the sliding window continues to slide, if the pressure gradient ΔF down First greater than the threshold Δf liq When the liquid scooping device 9 reaches the liquid surface, the host computer 1 will meet the threshold condition at the time point t a+y-1 As the inflection point of the pumping pressure, y is the sliding times of the pumping pressure judgment window. y is a natural number.

[0083] If the pressure gradient ΔF up After it is greater than the threshold Δf liq When the host computer 1 meets the threshold condition at time t a+z-1 As the inflection point of the upper pumping pressure, z is the sliding times of the upper pumping pressure judgment window, and z is a natural number.

[0084] In order to eliminate the interference of data fluctuations and ensure more accurate calculation results, the liquid level recognition algorithm also includes the following judgment conditions:

[0085] Condition (1): The upper computer 1 performs square linear fitting on the upper and lower pressures of the pumping pressure within b points starting from the inflection point of the upper and lower pressures of the pumping pressure, where b is preferably a natural number between 10 and 20, to determine whether the upper and lower pressures of the pumping pressure change in the same trend, that is, the slope of the upper and lower pressures of the pumping pressure change function is positive, and the slope difference is less than the threshold value Δk. The threshold value Δk is determined based on field experiments. Since the upper and lower pressures of the pumping pressure are liquid pressures after the liquid bailing pumping device 9 enters the liquid surface, the pressure change rates are the same, so that the slopes of the upper and lower pressures of the pumping pressure change functions differ very little.

[0086] Condition (2): The host computer 1 calculates the wire tension and finds the tension change ΔF within the data points of the upper pressure inflection point and the lower pressure inflection point respectively. s, determine whether |ΔF is satisfied s |>Δf s Δf s is the tension change threshold. s Determined according to on-site experiments. Because when the liquid-bailing pumping device 9 enters the liquid surface, the liquid has buoyancy, so the wire tension will change.

[0087] If the above conditions (1) and (2) are met at the same time, the upper computer 1 determines: the pumping pressure inflection point t a+y-1 The wire depth h at this time a+y-1 As the liquid depth h liq , that is, h liq =h a+y-1 ;

[0088] If the condition is not met, the sliding window continues to search for the upper pressure inflection point and the lower pressure inflection point of the pumping.

[0089] If conditions (1) and (2) are not met until the window slides to the end of the data, the host computer 1 determines that no liquid has been collected this time and ends the data analysis.

[0090] Step S5, after the upper computer 1 completes the liquid level identification, the upper computer 1 runs the liquid discharge algorithm again, and by analyzing the data curve, finds out the depth of the wire pull-up point, the depth of the needle valve opening point and the depth of the needle valve closing point after liquid discharge is completed, thereby obtaining the liquid scooping height of the wellhead.

[0091] like Figure 6 The liquid discharge algorithm includes the wire pull-up judgment algorithm, the needle valve opening point judgment algorithm, the needle valve closing point judgment algorithm and the volume method.

[0092] The upper computer 1 first runs the wire pulling judgment algorithm, traverses the wire lowering depth data of the entire wire lowering depth data curve A, finds the maximum wire lowering depth, analyzes the wire lowering depth data from the point where the maximum wire lowering depth is located, determines the wire pulling time point, and uses the wire depth at the wire pulling time point as the wire bailing depth, and calculates the current bailing height h get .

[0093] Specifically, the wire pull-up judgment algorithm is:

[0094] The host computer 1 traverses the steel wire lowering depth data h(t) of the entire steel wire lowering depth data curve, and takes the time point corresponding to the maximum steel wire lowering depth as the time point t of the longest steel wire lowering position max , starting from this position, calculate the change in wire length Δh1 of the adjacent points, then:

[0095] Δh1=h x+1 -hx ; (3)

[0096] (3) In the formula, h x From time point t max The starting point x is the wire depth at this time, h x+1 It is the wire depth at the next point of point x.

[0097] When Δh1<-1m, 10 points are taken from x points as sliding windows, each sliding step is one point, x is the number of points in the sliding window, x is preferably a natural number between 100-200, and the depth of the 10th point in the sliding window is taken as h 9+k+x , the depth of the first point is h k-1+x , k is the number of sliding windows, k is preferably a natural number between 10 and 20, then:

[0098] Δh 10 =h 9+k+x -h k-1+x ; (4)

[0099] (4) In the formula, Δh 10 It represents the difference between the wire depth at the 10th point and the 1st point in the sliding window. If Δh 10 When <-10m, it is determined that t k-1+x Point is the point where the wire is pulled up, and the length of the wire at this time is recorded. k-1+x As the depth of the wire pulling point, calculate the height of the liquid removal h get ,but:

[0100] h get =h k-1+x -h liq ; (5)

[0101] (5) In the formula, h k-1+x is the depth of the wire pull-up point, i.e., the first point t in the k-time sliding window k-1+x The length of the steel wire h k-1+x .

[0102] Step S6, the upper computer 1 runs the needle valve opening point judgment algorithm, traverses the upper pumping pressure data of the entire upper pumping pressure data curve E, finds the maximum value of the upper pumping pressure data, analyzes the upper pumping pressure data from the maximum value time point of the upper pumping pressure data, and obtains the discharge needle valve opening time point t op The wire depth at this time is taken as the suction depth h of the needle valve opening point open .

[0103] Specifically, the host computer 1 runs the needle valve opening point judgment algorithm, including the following steps:

[0104] Step S61: the host computer 1 traverses the upper pressure data F of the entire upper pressure data curve E. up , take the maximum value at time t upmax , as the starting point p of the analysis, starting from this point p, c points are taken as the sliding window, c is preferably a natural number between 10 and 20, each sliding step is one point, and the pressure of the cth point is taken as F c-1+i+p , the pressure at the first point is F i-1+p , calculate the pressure change ΔF c , i is the number of window sliding times, i is preferably a natural number between 100-200, then:

[0105] ΔF c =F c-1+i+p -F i-1+p ; (6)

[0106] Step S62, determine whether ΔF is satisfied c <-Δf c , Δf c A threshold value can be set. If it is not satisfied, step S63 is executed; if it is satisfied, step S64 is executed; threshold Δf c According to the field experiment setting, the upper pressure of the pumping device 9 is increased by pulling the liquid scoop upward until the needle valve is opened to release the pressure, and the upper pressure of the pumping drops rapidly. Therefore, the threshold value Δf c It is the threshold value for judging the pressure difference at the needle valve opening point.

[0107] Step S63, continue sliding the window to find the point;

[0108] Step S64, the wire tension F s Make a judgment and take the tension at point c as F s c-1+i+p , the pressure at the first point is F s i-1+p , calculate the tension change ΔF s :

[0109] ΔF s =F s c-1+i+P -F s i-1+D ; (7)

[0110] Step S65, determine whether ΔF is satisfied s <-Δf s c , Δf s c The threshold value can be set; the threshold value Δf s c According to the field experiment setting, the pressure on the pumping device 9 increases when the liquid is pulled upward, and the wire tension increases until the needle valve is opened to release the pressure, the pressure on the pumping drops rapidly, and the wire tension also decreases rapidly, so the threshold value Δf s c It is the threshold value for judging the difference in wire tension at the needle valve opening point;

[0111] If not, execute step S67; if satisfied, execute step S66;

[0112] Step S66, then the time point t i-1+p Point is the needle valve opening point t op , the length of the steel wire at this time is h i-1+p , the wire length h at this time i-1+p As the needle valve opens the pumping depth h open ;

[0113] Step S67, return to step S63.

[0114] Step S7, the upper computer 1 runs the needle valve closing point judgment algorithm, starting from the wellhead discharge needle valve opening point, traverses the wellhead tubing pressure data of the entire wellhead tubing pressure data curve A, determines the needle valve closing point where the discharge is completed, takes the wire depth at the needle valve closing point as the pumping depth of the needle valve closing point, and subtracts the pumping depth of the needle valve closing point from the pumping depth of the needle valve opening point to obtain the wellhead discharge height h d .

[0115] Specifically, the host computer 1 runs the needle valve closing point judgment algorithm, which is as follows: after the needle valve opening point is determined, the host computer 1 queries the wellhead tubing pressure data F from the needle valve opening point backwards o , take d points as the sliding window, d is preferably a natural number between 100-150, each sliding step is one point, calculate the data in the window and sort them, and find the maximum value F omax and the minimum value F omin , and calculate F omax and F omin The difference ΔF o ;but:

[0116] ΔF o =F omax -F omin ; (8)

[0117] Determine whether the following conditions are met at the same time: ①ΔF o <Δf o ,②F omax <f oc ; Δf o ΔF o The decision threshold, threshold Δf o It can be set and determined according to field tests. After the needle valve is closed, the wellhead tubing pressure area is stable and there will be a small amount of pressure fluctuation, but the fluctuation is small. Therefore, the threshold Δf o is the threshold value for judging the oil pressure difference at the closing point of the needle valve; f oc The oil pressure threshold when closing the needle valve, threshold f oc The setting conditions are determined according to field tests;

[0118] If not, continue to slide the window to find the point; if both ① and ② are satisfied, the maximum value F is determined. omax <f oc And ΔF o <Δf o ; then the m-1th point is taken as the needle valve closing point t0, and the wire depth h at this point m-1 When the needle valve is closed after the drainage is completed, the suction depth h of the needle valve is closed close , m is the number of window sliding times, m is preferably a natural number between 10-20; at this time, the wellhead discharge height h can be obtained d for:

[0119] h d =h open -h close ; (9)

[0120] (9) In the formula, h open is the pumping depth when the needle valve is opened, h close It is the pumping depth when the needle valve is closed.

[0121] Step S8: The host computer 1 obtains the wellhead discharge height h. d , the host computer 1 runs the volume method to calculate the volume V of the liquid discharged this time, and according to the height h of the liquid get and wellhead discharge height h d Calculate the pumping loss Δh LR and the leakage rate η LR , where the volume V of the liquid discharged from the wellhead is:

[0122]

[0123] In formula (10), D is the inner diameter of the oil pipe; at the same time, the height of the liquid removal h can be obtained get With discharge height h d The leakage Δh LR and the leakage rate η LR for:

[0124] Δh LR =h get -h d ; (11)

[0125]

[0126] Step S9: the host computer 1 calculates the liquid level depth h obtained in step 4. liq , the wellhead discharge height h obtained in step 7 d Calculate the expected next liquid level depth for:

[0127]

[0128] Step S10, the host computer 1 determines whether to dredge the well according to the gas well pressure. If the gas well pressure returns to the original normal pressure, the well has been dredged. If the well is dredged, the liquid bailing operation is terminated. If the well is not dredged, the liquid level depth of the next dredge is predicted. The liquid bailing pumping device 9 is lowered to baile the liquid, and steps S1 to S10 are repeated until the well is unblocked.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid level recognition and liquid discharge volume metering system based on steel wire closed liquid discharge, characterized in that: The invention comprises a steel wire closed liquid discharge vehicle (8), a liquid bailing and pumping device (9), a gas production tree (12) and a metering device. The lower end of the gas production tree (12) is connected to an oil pipe (10). The steel wire closed liquid discharge vehicle (8) suspends the liquid bailing and pumping device (9) and lowers it into the oil pipe (10). The metering device comprises an upper computer (1), an oil pressure transmitter (4), a casing pressure transmitter (5), a steel wire metering module (6) and a downhole temperature and pressure meter (7). The oil pressure transmitter (4) and the casing pressure transmitter (5) are respectively arranged on the gas production tree (12) for collecting wellhead oil pipe pressure data and wellhead oil pipe casing pressure data. The steel wire metering module (6) is connected to the steel wire closed liquid discharge vehicle (8) for collecting steel wire tension data and steel wire lowering depth data; a pair of downhole temperature and pressure gauges (7) are respectively arranged at the upper and lower ends of the liquid bailing and pumping device (9) and are carried by the liquid bailing and pumping device (9) into the oil pipe (10) for collecting downhole temperature and pressure data; the upper computer (1) is wirelessly connected to the oil pressure transmitter (4), the casing pressure transmitter (5), the steel wire metering module (6) and the downhole temperature and pressure gauge (7) for receiving the collected liquid bailing data and then measuring the downhole liquid level depth and the amount of liquid discharged; The closing and opening time points of the needle valve are determined based on the pressure data, and the difference in wire depth at different time points is used as the wellhead discharge height of the discharge volume.

2. The liquid level identification and liquid discharge volume metering system based on steel wire closed liquid discharge according to claim 1 is characterized in that: The metering device further comprises a surface controller (2) and a wellhead wireless communication module (3); the wellhead wireless communication module (3) is arranged at the upper end of the gas production tree (12) and is used for wirelessly transmitting the liquid salvage data to the surface controller (2); and the surface controller (2) is used for wirelessly transmitting the liquid salvage data to the host computer (1).

3. A well cleaning method based on steel wire closed drainage, using the liquid level identification and drainage volume metering system based on steel wire closed drainage as described in any one of claims 1-2, characterized in that: The following steps are involved: Step S1, the metering device collects the liquid scooping data of the liquid scooping process in real time, and after a liquid scooping is completed, the liquid scooping data is wirelessly transmitted to the host computer (1); Step S2, the upper computer (1) plots the liquid bailing data into a data curve, wherein the data curve includes a steel wire tension data curve, a steel wire lowering depth data curve, a wellhead tubing pressure data curve, a wellhead tubing casing pressure data curve, a downhole temperature data curve, a pumping upper pressure data curve, and a pumping lower pressure data curve; Step S3, the upper computer (1) calculates the upper pumping pressure F according to the upper pumping pressure data curve. up (t), pumping pressure F of the pumping pressure data curve down (t) and the wellhead tubing pressure data curve of the wellhead tubing pressure F o Determine the starting needle valve closing point t0; Step S4, starting from the needle valve closing point t0, the upper computer (1) analyzes the upper pumping pressure data curve, the lower pumping pressure data curve and the steel wire lowering depth data curve to determine the time point when the liquid scooping pumping device (9) contacts the liquid surface, and obtains the steel wire depth when the liquid scooping pumping device (9) contacts the liquid surface according to the time point when the liquid scooping pumping device (9) contacts the liquid surface, and takes the steel wire depth when the liquid scooping pumping device (9) contacts the liquid surface as the liquid surface depth h. liq ; If the upper computer (1) cannot determine the time point when the liquid scooping and pumping device (9) contacts the liquid surface, it is determined that no liquid has been scooped this time; Step S5, the host computer (1) traverses the entire wire lowering depth data curve to determine the wire pulling time point, and uses the wire depth at the wire pulling time point as the wire scooping depth, and calculates the current scooping height h get ; Step S6, the host computer (1) traverses the entire pumping pressure data curve to determine the needle valve opening time point, and uses the wire depth at the needle valve opening time point as the pumping depth at the needle valve opening point. ; Step S7, the host computer (1) traverses the entire wellhead oil pipe pressure data curve to determine the needle valve closing point t0, and uses the wire depth at the needle valve closing point t0 as the needle valve closing point pumping depth ,but: Wellhead drainage height h d = Needle valve opening point pumping depth - Pumping depth at needle valve closing point ; Step S8, the host computer (1) calculates the wellhead discharge height h d Calculate the volume V of this discharge: ; Where D is the inner diameter of the oil pipe; The upper computer (1) calculates the height of the liquid according to the height h get and wellhead discharge height h d Calculate the amount of leakage from the pump and the leakage rate η LR : , ; Step S9, the host computer (1) determines the wellhead discharge height , liquid level depth h liq Calculate and predict the next liquid level depth : ; Step S10, the host computer (1) determines whether the well is open according to the gas well pressure. If the well is open, the liquid bailing operation is terminated; if the well is not open, the liquid level depth of the next liquid bailing operation is predicted. Repeat steps S1-S10 to lower the liquid bailing pumping device again to perform liquid bailing operations until the well is unblocked.

4. The well cleaning method based on steel wire closed drainage according to claim 3 is characterized in that: In step S3, the starting needle valve closing point t0 is determined by: pumping the upper pressure F up (t), pumping pressure F down (t) and wellhead tubing pressure F o satisfy: The time change point is taken as the starting needle valve closing point t0; The pumping pressure F up (t), pumping pressure F down (t) and wellhead tubing pressure F o Poor threshold.

5. The well cleaning method based on steel wire closed drainage according to claim 3 is characterized in that: In step 4, the host computer (1) analyzes the upper pressure data curve, the lower pressure data curve and the steel wire lowering depth data curve, specifically including: calculating the time points in the steel wire lowering process respectively. and The upper pressure or lower pressure of the pumping during the pumping process changes with the depth of the steel wire lowering h. (t) Gradient of change : ; Where: a is the number of points in the sliding window, i is the number of window sliding times, and a and i are natural numbers; For time point The pressure of The pressure of for The wire depth at For time point Wire depth when Negative value or below the threshold Δf liq When the liquid extraction device (9) has not reached the liquid surface, Greater than the threshold Δf liq When the liquid is sucked out, it is determined that the liquid suction device (9) has reached the liquid surface.

6. The well cleaning method based on steel wire closed drainage according to claim 5 is characterized in that: The gradient Including the gradient of pumping pressure and the pressure gradient on the pump ; If the pressure gradient under pumping First greater than the threshold Δf liq When the liquid scooping and pumping device (9) reaches the liquid surface, the time point As the inflection point of the pumping pressure, y is the number of sliding times of the pumping pressure judgment window; if the gradient of the pumping pressure After it is greater than the threshold Δf liq At this time, the time point As the inflection point of the upper pumping pressure, z is the sliding number of the upper pumping pressure judgment window, and y and z are natural numbers.

7. The well cleaning method based on steel wire closed drainage according to claim 6 is characterized in that: The host computer (1) analyzes the upper pressure data curve of the pumping, the lower pressure data curve of the pumping and the wire lowering depth data curve, and also includes: The upper computer (1) fits the upper pumping pressure at the inflection point of the lower pumping pressure and the lower pumping pressure at the inflection point of the upper pumping pressure to determine whether the slope of the change function of the upper pumping pressure and the lower pumping pressure is positive and the slope difference is less than a threshold value Δk; The upper computer (1) calculates the wire tension data curve of the wire tension before and after the upper pressure inflection point and the lower pressure inflection point of the pumping, and calculates the wire tension change ΔF s , determine whether |ΔF is satisfied s |>Δf s , Δf s is the wire tension change threshold; If both conditions are met, then the depth of the steel wire at the pressure inflection point is As the liquid depth h liq ; If it is not satisfied, the window will continue to slide to find the upper pressure inflection point and the lower pressure inflection point of the pumping. If the window slides to the end and is not satisfied, it is determined that no liquid is collected this time.

8. The well cleaning method based on steel wire closed drainage according to claim 3 is characterized in that: In step 5, the host computer (1) traverses the entire wire lowering depth data curve to determine the wire pulling time point, and uses the wire depth at the wire pulling time point as the wire scooping depth, and calculates the current scooping height h get Specifically, the host computer (1) traverses the entire wire lowering depth data curve, and takes the time point corresponding to the maximum wire lowering depth as the time point t at which the wire is at the longest lowering position. max , calculate the change in wire length ∆h1 of the adjacent points from this position, then: ; Among them, x is the time from the time point t max The starting point is x, which is a natural number, h x From time point t max The starting point x is the wire depth at this time, h x+1 is the wire depth of the next point of point x; When ∆h1<-1m is satisfied, 10 points are taken from point x as the sliding window, each sliding step is one point, and the depth of the 10th point is taken as , the first point depth is , k is the number of sliding windows, k is a natural number, then: ; Where ∆h 10 It represents the difference between the wire depth at the 10th point and the 1st point in the sliding window. If ∆h 10 <-10m, judge The point is the wire pull-up point, record the wire length at this time As the depth of the wire pull-up point, The height of the liquid is h get ,but: .

9. The well cleaning method based on steel wire closed drainage according to claim 3 is characterized in that: In step 6, the upper computer (1) traverses the entire pumping pressure data curve to determine the needle valve opening time point, and the wire depth at the needle valve opening time point is used as the pumping depth at the needle valve opening point. , specifically including: Step S61, the host computer (1) traverses the entire downhole pressure data curve and takes the maximum value point position As the starting point p of the analysis, c points are taken from this point as the sliding window, each sliding step is one point, and the pressure of the cth point is taken as , the first point pressure is , calculate the pressure change , i is the number of window sliding times, c and i are natural numbers, then: ; Step S62, determine whether < , is the threshold; if not satisfied, execute step S63; if satisfied, execute step S64; Step S63, continue sliding the window to find the point; Step S64, the wire tension F s Make a judgment and take the tension at point c as , the first point pressure is , calculate the change in tension ,but: ; Step S65, determine whether s <- s , is the threshold value; If not, execute step S67; if satisfied, execute step S66; Step S66, then the time point Point is the needle valve opening point t op , the length of the steel wire at this time is Pumping depth h as the needle valve opening point open ; Step S67, return to step S63.

10. The well cleaning method based on steel wire closed drainage according to claim 3, characterized in that: In step 7, the host computer (1) traverses the entire pumping pressure data curve to determine the needle valve opening time point, specifically: the host computer (1) queries the wellhead oil pipe pressure data F from the needle valve opening point backward o , sliding window to find the maximum value and minimum value ,but and The difference for: ; Determine whether both are satisfied: < and <f oc , ; If not satisfied, continue to slide the window; if satisfied at the same time, then the m-1th point at this time is used as the needle valve closing point t0, m is the number of window sliding times, and m is a natural number.

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