Method for discriminating intermittent liquid outlet indicator diagram of rod-pumped well

Abstract

The invention belongs to the technical field of rod-pumped well extraction, and particularly provides a rod-pumped well intermittent liquid outlet indicator diagram discrimination method, which comprises the following steps: utilizing a ground indicator diagram acquired in real time to obtain the maximum and minimum load mean values of the ground indicator diagram through a geometrical characteristic method and a standard error method; then the maximum load mean value standard deviation and the minimum load mean value standard deviation of all the sample ground indicator diagrams are obtained respectively, the intermittent liquid outlet well is recognized according to a specific threshold value, continuous and automatic judgment of intermittent liquid outlet of the rod-pumped well is achieved, the oil well intermittent opening intelligent level is effectively improved, and the oil well intermittent opening efficiency is improved. The problems that the workload is large, the efficiency is low, the development requirement of intelligent intermittent pumping of an oil field cannot be met, and the method for determining the intermittent liquid outlet condition of the oil well is high in cost, high in failure rate and incapable of being effectively applied in the existing manual statistical analysis for determining the liquid outlet condition of the oil well are solved. The method meets the development requirement of intelligent intermittent pumping of an oil field, is high in judgment accuracy, reduces the workload, is high in efficiency, is low in cost, and is effectively applied to actual production.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical production of oil pumping wells, and in particular relates to a method for distinguishing an intermittent liquid discharge indicator diagram of an oil pumping well. Background Art

[0002] For the "three lows" oil fields with low permeability, low production and low pressure, as the production of oil wells decreases year by year, the contradiction between the formation fluid supply capacity and the production parameters of the pumping wells becomes increasingly prominent, and intermittent fluid wells begin to appear in large numbers. If these wells continue to be mined around the clock, it will inevitably cause energy waste and affect the life of the downhole pumping pump. Therefore, oil fields mostly adopt intermittent pumping for production. With the advancement of oilfield intelligence and the construction of the Internet of Things, inter-well pumping, as one of the most realistic and potential technical means for oilfields to control and reduce investment, is also facing the transformation from manual to intelligent. One of the important bases for determining the inter-well pumping system is to clarify the intermittent fluid discharge law of the oil well, which requires timely acquisition of the fluid discharge status of the oil well for analysis. However, as the number of inter-well pumping wells in oil fields gradually increases, the workload of manual statistical analysis to determine the fluid discharge status of the oil well becomes huge and inefficient, and cannot meet the development needs of intelligent inter-well pumping in oil fields.

[0003] After consulting relevant patents, there are currently two methods used to obtain the liquid discharge of oil wells: one is to use a mechanical device to obtain the liquid discharge, involving the patent "An intermittent oil well liquid discharge indication and non-return device" (CN201120382347.9), which uses the wellhead mechanical device to flip to determine the wellhead liquid discharge status. This method is relatively direct, but the cost is high and the failure rate is high and it cannot meet the needs of oil field digital development; the other method is mainly to use the analysis of the oil well indicator diagram to determine the intermittent liquid discharge of the oil well. This method is currently mainly used for oil well working condition diagnosis and production calculation, but there is still a lack of effective application for the judgment of intermittent liquid discharge in oil wells, and there is still room for further exploration and utilization. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem that the manual statistical analysis in the prior art to determine the intermittent liquid discharge status of the oil well is labor-intensive and inefficient, and cannot meet the development needs of intelligent intermittent pumping in the oil field; the second purpose is to overcome the problem that the method for determining the intermittent liquid discharge status of the oil well in the prior art is high in cost, high in failure rate, and cannot be effectively applied.

[0005] To this end, the present invention provides a method for distinguishing an intermittent liquid discharge indicator diagram of a pumping well, comprising the following steps:

[0006] 1) Collect the ground performance diagrams of the pumping units within the target time period;

[0007] 2) converting all the ground dynamometer diagrams collected in step 1) into pump dynamometer diagrams;

[0008] 3) Solve the load line B_FMU on the pump dynamometer card and the load line B_FMD below the pump dynamometer card for each pump dynamometer card according to the four geometric feature points obtained from each pump dynamometer card; the four geometric feature points are the leftmost point P in the pump indicator diagram L , the rightmost point P R , the uppermost point P U , and the lowermost point P D ;

[0009] 4) Determine the opening and closing points of the four valves in each pump dynamometer card; the opening and closing points of the four valves are the fixed valve opening point P SO , the fixed valve closing point P SC , the traveling valve opening point P TO and the traveling valve closing point P TC ;

[0010] 5) Determine the opening and closing points of the four valves in each surface indicator diagram according to the opening and closing points of the four valves in each pump dynamometer card;

[0011] 6) Solve the standard deviation of the maximum load mean DM_FMU and the standard deviation of the minimum load mean DM_FMD of each surface indicator diagram;

[0012] 7) Judge whether each surface indicator diagram discharges liquid according to the standard deviation of the maximum load mean and the standard deviation of the minimum load mean of each surface indicator diagram;

[0013] 8) Determine the liquid-producing period and non-liquid-producing period of the oil well within the target time period according to whether each surface indicator diagram discharges liquid.

[0014] Preferably, in step 3), both the load line B_FMU on the pump dynamometer card and the load line B_FMD below the pump dynamometer card are solved by the iterative method. Let B_BAND = (F D - F U ) / 8, and B_BAND is the threshold; the calculation method of the load line B_FMU on the pump dynamometer card is: take an upward stroke, start iterative calculation from point P L to point P R , and the iterative condition is |F(i) - F U | < B_BAND; the calculation method of the load line B_FMD below the pump dynamometer card is: take a downward stroke, start iterative calculation from point P R to point P L , and the iterative condition is |F(i) - F D | < B_BAND.

[0015] Preferably, the calculation formula of the load line B_FMU on the pump dynamometer card is:

[0016]

[0017] Among them, Fi is the sample load value at point i, U i is the sample position value of point i.

[0018] Preferably, the calculation formula of the load line B_FMD under the pump work diagram is:

[0019]

[0020] Preferably, the method of determining the switch points of the four valves in each pump performance diagram in step 4) is the same and both adopt the method of solving the standard deviation of the average load change through the stationary point.

[0021] Preferably, the method of solving the standard deviation of the average load change by the stationary point determines the fixed valve opening point P in each pump power diagram. SO The method comprises the following steps:

[0022] 4.1) The pump performance diagram is divided into F1 area, F2 area, F3 area and F4 area, where the fixed valve opening point P SO In the F1 area, fixed valve closing point P SC In the F2 area, the floating valve opening point P TO In the F3 area, the floating valve closing point P TC In the F4 area;

[0023] 4.2) In the F1 region, between point P1 and point K, assume that one point is the fixed valve opening point P SO , then from P1 to P SO , the standard deviation of load variation is shown in formula (3)

[0024]

[0025] Where: F1, F2, ..., F n : P1 to P SO All load production variation sample data;

[0026] The average value of all load changes from P1 to PSO;

[0027] n: is the number of load changes between sample points;

[0028] From P SO At point K, the standard deviation of load change is shown in formula (4):

[0029]

[0030] Among them: F n+1 ,F n+2 ,……,F n+m :P SOSample data of all load production changes to K;

[0031] P SO The mean value of all load changes to K;

[0032] m: is the number of load changes between sample points;

[0033] The standard error of the load change between adjacent points in the above two samples to the overall average load change is shown in formula (5):

[0034] Z(P SO )=σ1+σ2 (5)

[0035] When Z=min{Z(P SO )}, P SO That is the fixed valve opening point;

[0036] 4.3) Using the method in step 4.2), the fixed valve closing point P is obtained. SC , Floating valve opening point P TO and the travel valve closing point P TC .

[0037] Preferably, the calculation method of the maximum load mean DM_FMU standard deviation of the ground dynamometer diagram in step 6) is shown in formula (6):

[0038]

[0039] Among them: N≤144.

[0040] Preferably, the calculation method of the minimum load mean DM_FMD standard deviation of the ground dynamometer diagram in step 6) is shown in formula (7):

[0041]

[0042] Preferably, the method of determining whether each ground dynamometer chart has liquid discharge in step 7) is:

[0043] When σ DM_FMU <1 and This means that this ground indicator diagram does not discharge fluid at this time;

[0044] When σ DM_FMU <1 and This means that liquid is leaking from this ground indicator diagram at this time.

[0045] Preferably, the target time period of step 1) is one day, and a ground dynamometer diagram is collected every 10 minutes.

[0046] Beneficial effects of the present invention:

[0047] The method for distinguishing the intermittent liquid discharge indicator diagram of the pumping well provided by the present invention mainly utilizes the surface indicator diagram collected in real time, and is carried out through the following 8 steps: 1) collecting the surface indicator diagram of the pumping unit within the target time period; 2) converting all the surface indicator diagrams collected in step 1) into pump diagrams; 3) solving the upper load line B_FMU and the lower load line B_FMD of the pump diagram in each pump diagram according to the four geometric feature points obtained from each pump diagram; the four geometric feature points are the leftmost point P in the pump diagram. L , the rightmost point P R , the top point P U , the lowest point P D ; 4) Determine the switch points of the four valves in each pump diagram; the switch points of the four valves are fixed valve opening points P SO , Fixed valve closing point P SC , Floating valve opening point P TO and the travel valve closing point P TC ; 5) Determine the switching points of the four valves in each ground dynamometer diagram according to the switching points of the four valves in each pump dynamometer diagram; 6) Solve the maximum load mean DM_FMU standard deviation and the minimum load mean DM_FMD standard deviation of each ground dynamometer diagram; 7) Determine whether each ground dynamometer diagram is producing liquid according to the maximum load mean standard deviation and the minimum load mean standard deviation of each ground dynamometer diagram; 8) Determine the liquid production period and non-liquid production period of the oil well within the target time period according to whether each ground dynamometer diagram is producing liquid; Continuous and automatic judgment of intermittent liquid production of pumping wells is realized, which effectively improves the intelligent level of intermittent opening of oil wells and meets the development needs of intelligent intermittent pumping in oil fields. The judgment accuracy rate reaches more than 95%, which reduces the workload, has high efficiency, low cost, and can be effectively applied to actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention will be further described in detail below with reference to the accompanying drawings.

[0049] Figure 1 It is a flow chart of the method for distinguishing the intermittent liquid output indicator diagram of a pumping well;

[0050] Figure 2 It is the composition diagram of the ground construction drawing;

[0051] Figure 3 It is the composition diagram of the pump work diagram;

[0052] Figure 4 It is the switch point search diagram of the four valves in the pump performance diagram;

[0053] Figure 5 It is an intermittent discharge curve. DETAILED DESCRIPTION

[0054] Embodiment 1:

[0055] like Figure 1-Figure 5 As shown, a method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well comprises the following steps:

[0056] 1) Collect the ground indicator diagram of the pumping unit within the target time period;

[0057] The ground dynamometer is a curve showing the relationship between the load and displacement of the pumping unit suspension point. It is obtained by synchronously collecting displacement sensors and load sensors from the pumping unit well RTU. A ground dynamometer contains 200 data points, each of which contains load displacement information. Figure 2 As shown in the figure, the horizontal axis of the ground indicator diagram is the displacement value, and the vertical axis is the load value.

[0058] Load line DM_FMU on the ground dynamometer diagram: from the fixed valve opening point to the fixed valve closing point, all the data points in between correspond to the load mean, also known as the maximum load mean of the ground dynamometer diagram.

[0059] The load line DM_FMD under the ground dynamometer diagram: from the opening point of the traveling valve to the closing point of the traveling valve, all the data points in the middle correspond to the load mean, also known as the minimum load mean of the ground dynamometer diagram.

[0060] Ground dynamometer load difference DM_FL: the difference between the mean value of the maximum load on the ground dynamometer and the mean value of the minimum load on the ground dynamometer.

[0061] 2) converting all the ground dynamometer diagrams collected in step 1) into pump dynamometer diagrams;

[0062] The relationship curve between the load and displacement at the connection between the sucker rod and the pump plunger is obtained by converting the ground indicator diagram into the pump diagram. The conversion method of the ground indicator diagram into the pump diagram is an existing technology, and its specific conversion method will not be introduced in detail here.

[0063] 3) Based on the four geometric characteristic points obtained from each pump performance diagram, solve the upper load line B_FMU and the lower load line B_FMD in each pump performance diagram; the four geometric characteristic points are the leftmost point P in the pump performance diagram L , the rightmost point P R , the top point P U , the lowest point P D ;(See Figure 3 )

[0064] 4) Determine the switch points of the four valves in each pump power diagram; the switch points of the four valves are fixed valve opening points P SO , Fixed valve closing point P SC , Floating valve opening point P TO and the travel valve closing point P TC ;

[0065] The standard error refers to the standard deviation of the sample mean in repeated equal-precision measurements, reflecting the degree of variation of the sample mean from the population mean. When the sample changes, the sample mean also changes, and at the same time, the degree of variation of the sample mean from the population mean also changes accordingly. Using this property of the standard error method, the points on the pump dynamometer card that are most likely to be the opening and closing of the traveling valve and the fixed valve can be deduced.

[0066] 5) Determine the opening and closing points of the four valves in each surface dynamometer card based on the opening and closing points of the four valves in each pump dynamometer card;

[0067] 6) Solve the standard deviation of the maximum load mean DM_FMU and the standard deviation of the minimum load mean DM_FMD of each surface dynamometer card;

[0068] 7) Determine whether each surface dynamometer card discharges fluid based on the standard deviation of the maximum load mean and the standard deviation of the minimum load mean of each surface dynamometer card;

[0069] 8) Determine the fluid-producing period and the non-fluid-producing period of the oil well within the target time period based on whether each surface dynamometer card discharges fluid.

[0070] The method for discriminating the intermittent fluid-producing dynamometer card of a pumping unit well provided by the present invention mainly uses the real-time collected surface dynamometer card. Through the above 8 steps, the continuous and automatic discrimination of the intermittent fluid production of the pumping unit well is realized, effectively improving the intelligent level of the intermittent operation of the oil well, meeting the development needs of intelligent intermittent pumping in the oilfield, with a judgment accuracy rate of over 95%, reducing the workload, high efficiency, low cost, and can be effectively applied to actual production.

[0071] Preferably, in step 3), both the load line B_FMU on the pump dynamometer card and the load line B_FMD on the lower part of the pump dynamometer card are solved by the iterative method. Let B_BAND = (F D -F U ) / 8, and B_BAND is the threshold; the calculation method of the load line B_FMU on the pump dynamometer card is: take an upstroke, start iterative calculation from point P L to point P R , and the iterative condition is |F(i)-F U |<B_BAND; the calculation method of the load line B_FMD on the lower part of the pump dynamometer card is: take a downstroke, start iterative calculation from point P R to point P L , and the iterative condition is |F(i)-F D |<B_BAND.

[0072] According to the actual on-site operation, let B_BAND = (F D -F U ) / 8, which has the best practicability and applicability and high calculation accuracy.

[0073] Preferably, the calculation formula of the load line B_FMU on the pump work diagram is:

[0074]

[0075] Among them, F i is the sample load value at point i, U i is the sample position value of point i.

[0076] Preferably, the calculation formula of the load line B_FMD under the pump work diagram is:

[0077]

[0078] Preferably, the method of determining the switch points of the four valves in each pump performance diagram in step 4) is the same and both adopt the method of solving the standard deviation of the average load change through the stationary point.

[0079] Preferably, the method of solving the standard deviation of the average load change by the stationary point determines the fixed valve opening point P in each pump power diagram. SO The method comprises the following steps (see Figure 4 ):

[0080] 4.1) The pump performance diagram is divided into F1 area, F2 area, F3 area and F4 area, where the fixed valve opening point P SO In the F1 area, fixed valve closing point P SC In the F2 area, the floating valve opening point P TO In the F3 area, the floating valve closing point P TC In the F4 area;

[0081] With fixed valve opening point P SO For example, from point P1 to the fixed valve opening point P SO At this stage, the sucker rod string is in a loaded state, so in the pump performance diagram, from point P1 to the fixed valve opening point P SO The load variation between sample points in the region is large; similarly, the load variation from the fixed valve opening point to point K is small. Here, the load variation between adjacent points in the region is set as a single sample point, and the average load variation between all adjacent points in the region is set as the average load variation of the overall sample. Therefore, the standard deviation of the average load variation can be solved by the stationary point to find the fixed valve opening point P SO .

[0082] 4.2) In the F1 region, between point P1 and point K, assume that one point is the fixed valve opening point P SO , then from P1 to P SO , the standard deviation of load variation is shown in formula (3)

[0083]

[0084] Where: F1, F2, ..., F n : P1 to P SO All load production variation sample data;

[0085] The average value of all load changes from P1 to PSO;

[0086] n: is the number of load changes between sample points;

[0087] From P SO At point K, the standard deviation of load change is shown in formula (4):

[0088]

[0089] Among them: F n+1 ,F n+2 ,……,F n+m :P SO Sample data of all load production changes to K;

[0090] P SO The mean value of all load changes to K;

[0091] m: is the number of load changes between sample points;

[0092] The standard error of the load change between adjacent points in the above two samples to the overall average load change is shown in formula (5):

[0093] Z(P SO )=σ1+σ2 (5)

[0094] When Z=min{Z(P SO )}, P SO That is the fixed valve opening point;

[0095] 4.3) Using the method in step 4.2), the fixed valve closing point P is obtained. SC , Floating valve opening point P TO and the travel valve closing point P TC .

[0096] Through the above method, the remaining three points (fixed valve closing point P SC , Floating valve opening point P TO and the travel valve closing point P TC After determining the four valve switch points of the pump power diagram, the four valve switch points of the ground indicator diagram can be inferred.

[0097] Generally speaking, the intermittent flow of liquid from oil wells is difficult to grasp. The flow intervals of oil wells are constantly changing, but the overall phenomenon is as follows: the maximum load does not change significantly, the minimum load becomes significantly smaller when liquid is flowing, and becomes significantly larger when no liquid is flowing, showing an overall sawtooth change trend.

[0098] In the actual judgment process, the ground dynamometer chart collected in one day is taken as a sample. The system generally collects a set of ground dynamometer chart data every 10 minutes as required, which means that there are a maximum of 144 sets of ground dynamometer chart data in one day. First, the four valve switch points of each ground dynamometer chart are determined according to the above method, and the maximum load mean DM_FMU and the minimum load mean DM_FMD of the ground dynamometer chart can be obtained. Then, the standard deviation of the maximum load mean and the standard deviation of the minimum load mean of all sample ground dynamometer charts are calculated respectively, and the intermittent liquid wells are identified according to the specific threshold. The specific algorithm process is as follows:

[0099] (1) Solve for the mean standard deviation of the maximum load on the ground dynamometer diagram

[0100] Preferably, the calculation method of the maximum load mean DM_FMU standard deviation of the ground dynamometer diagram in step 6) is shown in formula (6):

[0101]

[0102] Among them: N≤144.

[0103] (2) Solve the minimum load mean standard deviation of the ground dynamometer diagram

[0104] Preferably, the calculation method of the minimum load mean DM_FMD standard deviation of the ground dynamometer diagram in step 6) is shown in formula (7):

[0105]

[0106] (3) Criteria for determining intermittent discharge

[0107] Preferably, the method of determining whether each ground dynamometer chart has liquid discharge in step 7) is:

[0108] When σ DM_FMU <1 and This means that this (i-th) ground indicator diagram does not discharge liquid at this time;

[0109] When σ DM_FMU <1 and This means that this (the i-th) ground indicator diagram is leaking liquid at this time.

[0110] Preferably, the target time period of step 1) is one day, and a ground dynamometer diagram is collected every 10 minutes.

[0111] Embodiment 2:

[0112] A method for distinguishing an intermittent liquid discharge indicator diagram of a pumping well comprises the following steps:

[0113] Collect the ground indicator diagram of the oil pumping unit within the target time period; specifically, collect the ground indicator diagram data of the oil pumping unit through the oilfield SCADA control system, and select all the ground indicator diagram data of one day as samples;

[0114] 2) converting all the ground dynamometer diagrams collected in step 1) into pump dynamometer diagrams; specifically, converting the collected ground dynamometer diagrams into pump dynamometer diagrams by using a ground dynamometer diagram to pump dynamometer diagram conversion module and adopting a corresponding mathematical model;

[0115] 3) Based on the four geometric characteristic points obtained from each pump performance diagram, solve the upper load line B_FMU and the lower load line B_FMD in each pump performance diagram; the four geometric characteristic points are the leftmost point P in the pump performance diagram L , the rightmost point P R , the top point P U , the lowest point P D ;

[0116] Specifically, the pump power is obtained by analyzing the data of the pump power diagram. Figure 4 After the geometric feature points are obtained, the upper load line and the lower load line of the pump work diagram are obtained by using the iterative algorithm using the upper and lower load line module of the pump work diagram;

[0117] 4) Determine the switch points of the four valves in each pump power diagram; the switch points of the four valves are fixed valve opening points P SO , Fixed valve closing point P SC , Floating valve opening point P TO and the travel valve closing point P TC ;

[0118] Specifically, pump power Figure 4 The valve switch point solving module uses the upper load line of the pump work diagram, the lower load line of the pump work diagram and the standard error algorithm to obtain the opening and closing points of the fixed valve and the floating valve in the pump work diagram;

[0119] 5) Determine the switch points of the four valves in each ground indicator diagram according to the switch points of the four valves in each pump performance diagram;

[0120] Specifically, ground power indicator Figure 4 The valve switch point solution module is based on the pump power Figure 4 The four valve switch points of the ground indicator diagram can be inferred from the valve switch points;

[0121] 6) Calculate the maximum load mean DM_FMU standard deviation and the minimum load mean DM_FMD standard deviation of each ground dynamometer diagram;

[0122] 7) Determine whether each ground dynamometer diagram is leaking liquid based on the maximum load mean standard deviation and the minimum load mean standard deviation of each ground dynamometer diagram;

[0123] 8) Determine the period of oil wells producing and not producing liquid within the target time period based on whether each surface dynamometer diagram produces liquid;

[0124] 9) Export the corresponding curve through the drawing module ( Figure 5 ), the purple line in the figure (the fourth line from the top to the left) indicates The green line (based on the leftmost end, the first line from top to bottom) indicates The brown line (based on the leftmost end, the second line from top to bottom) represents the mean The blue line (based on the leftmost end, the third line from top to bottom) represents the minimum load mean line of the ground dynamometer diagram.

[0125] According to the diagnostic criteria for intermittent fluid discharge, the portion above the intersection of the blue line and the green line is the period of no fluid discharge, and the remaining portion is the period of fluid discharge.

[0126] The invention is based on the surface dynamometer data of the pumping well, and uses the geometric characteristic method and the standard error method to judge the intermittent liquid discharge of the pumping well. The surface dynamometer data of the oil field collected by the oil field SCADA system is used to obtain the maximum load mean value and the minimum load mean value of the surface dynamometer through the geometric characteristic method and the standard error method. Then, the maximum load mean standard deviation and the minimum load mean standard deviation of all sample surface dynamometers are respectively obtained, and the intermittent liquid discharge wells are identified according to the specific threshold value. Finally, the continuous automatic judgment of the intermittent liquid discharge of the pumping well is realized, and the judgment accuracy rate reaches more than 95%.

[0127] In the description of the present invention, it is necessary to understand that if there are terms such as "upper" and "lower" indicating an orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present invention.

[0128] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well, characterized in that: The steps include: 1) Collect the ground indicator diagram of the pumping unit within the target time period; 2) converting all the ground dynamometer diagrams collected in step 1) into pump dynamometer diagrams; 3) Based on the four geometric characteristic points obtained from each pump performance diagram, solve the upper load line B_FMU and the lower load line B_FMD in each pump performance diagram; the four geometric characteristic points are the leftmost point P in the pump performance diagram L , the rightmost point P R , the top point P U , the lowest point P D ; 4) Determine the switch points of the four valves in each pump power diagram; the switch points of the four valves are fixed valve opening points P SO , Fixed valve closing point P SC , Floating valve opening point P TO and the travel valve closing point P TC ; 5) Determine the switch points of the four valves in each ground indicator diagram according to the switch points of the four valves in each pump performance diagram; 6) Calculate the maximum load mean DM_FMU standard deviation and the minimum load mean DM_FMD standard deviation of each ground dynamometer diagram; 7) Determine whether each ground dynamometer diagram is leaking liquid based on the maximum load mean standard deviation and the minimum load mean standard deviation of each ground dynamometer diagram; 8) Determine the period of time during which the oil well produces liquid and the period during which the oil well does not produce liquid according to whether each surface dynamometer diagram produces liquid.

2. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 1, characterized in that: In step 3), both the load line B_FMU on the pump dynamometer card and the load line B_FMD below the pump dynamometer card are solved by the iterative method. Let B_BAND = (F D - F U ) / 8, where B_BAND is the threshold. The calculation method of the load line B_FMU on the pump dynamometer card is as follows: for one upstroke, start iterative calculation from point P L to point P R , and the iterative condition is |F(i) - F U | < B_BAND; the calculation method of the load line B_FMD below the pump dynamometer card is as follows: for one downstroke, start iterative calculation from point P R to point P L , and the iterative condition is |F(i) - F D | < B_BAND.

3. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 2, characterized in that: The calculation formula of the load line B_FMU on the pump work diagram is: Among them, F i is the sample load value at point i, U i is the sample position value of point i.

4. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 2, characterized in that: The calculation formula of the load line B_FMD under the pump work diagram is:

5. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 1, characterized in that: The method for determining the switch points of the four valves in each pump performance diagram in step 4) is the same and both use a method of solving the standard deviation of the average load change through the stationary point.

6. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 5, characterized in that: The method of solving the standard deviation of the average load change through the stationary point determines the fixed valve opening point P in each pump power diagram. SO The method comprises the following steps: 4.1) The pump performance diagram is divided into F1 area, F2 area, F3 area and F4 area, where the fixed valve opening point P SO In the F1 area, fixed valve closing point P SC In the F2 area, the floating valve opening point P TO In the F3 area, the floating valve closing point P TC In the F4 area; 4.2) In the F1 region, between point P1 and point K, assume that one point is the fixed valve opening point P SO , then from P1 to P SO , the standard deviation of load variation is shown in formula (3) Where: F1, F2, ..., F n : P1 to P SO All load production variation sample data; The average value of all load changes from P1 to PSO; n: is the number of load changes between sample points; From P SO At point K, the standard deviation of load change is shown in formula (4): Among them: F n+1 ,F n+2 ,……,F n+m :P SO Sample data of all load production changes to K; P SO The average value of all load changes to K; m: is the number of load changes between sample points; The standard error of the load change between adjacent points in the above two samples to the overall average load change is shown in formula (5): Z(P SO )=σ1+σ2 (5) When Z=min{Z(P SO )}, P SO That is the fixed valve opening point; 4.3) Using the method in step 4.2), the fixed valve closing point P is obtained. SC , Floating valve opening point P TO and the travel valve closing point P TC .

7. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 1, characterized in that: The calculation method of the maximum load mean DM_FMU standard deviation of the ground dynamometer diagram in step 6) is shown in formula (6): Among them: N≤144.

8. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 1, characterized in that: The calculation method of the minimum load mean DM_FMD standard deviation of the ground dynamometer diagram in step 6) is shown in formula (7):

9. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 1, characterized in that: The method of step 7) determining whether each ground dynamometer chart has liquid discharge is as follows: When σ DM_FMU <1 and This means that this ground indicator diagram does not discharge fluid at this time; When σ DM_FMU <1 and This means that liquid is leaking from this ground indicator diagram at this time.

10. The method for distinguishing the intermittent liquid discharge indicator diagram of a pumping well as claimed in claim 1, characterized in that: The target time period of step 1) is one day, and a ground dynamometer diagram is collected every 10 minutes.

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