CN111666536B - Polynomial fitting-based oil pumping unit indicator diagram acquisition method - Google Patents
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Abstract
The inventionThe utility model provides a pumping unit indicator diagram acquisition method based on polynomial fitting, which comprises the following steps: the wellhead controller RTU collects N point set load displacement original data according to the fixed interval of the stroke cycle, and reorganizes the indicator diagram data of the bottom dead center of the original data (S) i ,F i ) The method comprises the steps of carrying out a first treatment on the surface of the Data enhancement is carried out on the recombined displacement data points, and the data are expanded to (1+k) N point data sets S new The method comprises the steps of carrying out a first treatment on the surface of the Polynomial fitting is carried out on the data n times, and polynomial coefficients a are calculated 0 ,a 1 …a n To obtain Y (x) i ) A polynomial function; performing x on the obtained function i Substituting calculation to obtain new displacement data setBy means ofAnd removing the enhanced data to form new N-point indicator diagram dataThe method is simple and efficient, and the stability and accuracy of the acquired displacement data are improved well.
Description
Technical Field
The invention relates to the technical field of measurement, in particular to a polynomial fitting-based oil pumping unit indicator diagram acquisition method.
Background
The traditional method for acquiring displacement data by a smoothing method is difficult to meet the requirement on the accuracy of the work pattern data in the environment of a large-interference pumping unit, and can generate a lot of invalid work pattern data to influence the judgment of the well head condition by the large data and the calculation of the well head oil recovery, so that the effective rate of the work pattern data acquisition needs to be improved.
Disclosure of Invention
The object of the present invention is to solve at least one of the technical drawbacks.
Therefore, the invention aims to provide a polynomial fitting-based oil pumping unit indicator diagram acquisition method.
In order to achieve the above purpose, an embodiment of the present invention provides a method for collecting an indicator diagram of an oil pumping unit based on polynomial fitting, including the following steps:
step S1, the wellhead controller RTU collects N point set load displacement original data according to the fixed interval of the stroke cycle, and reorganizes the indicator diagram data of the bottom dead center of the original data (S) i ,F i ) The method comprises the steps of carrying out a first treatment on the surface of the Wherein { i|i.epsilon.1, 2,3, …, N }, S i Representing the displacement value of the i-th point, F i A load value representing the i-th point;
step S2, carrying out data enhancement on the displacement data points recombined in the step S1, and expanding the data points into (1+k) N point data sets S new ;
Step S3, performing polynomial fitting for n times on the data in the step S2, and calculating a polynomial coefficient a 0 ,a 1 …a n To obtain Y (x) i ) A polynomial function;
step S4, carrying out x on the function obtained in the step S3 i Substituting calculation to obtain new displacement data set
Step S5, using step S4And remove the enhanced data, combine F i Form new N-point indicator diagram data
Further, in the step S1, the range of N points is 200 to 250 points, and S is used at the same time i The lowest point reorganizes the work diagram data.
Further, in the step S2, the enhancement kN/2 is recorded as a new shift for each of the head and tail of the data pointData set S new WhereinThe increasing mode is as follows:
further, in said step S3, a fourth order and above polynomial is employed, based on a least squares fit, wherein for the dataset S new In x i As a function of the amount of the independent variable,is a dependent variable, wherein->And (3) performing polynomial fitting for n times by adopting a least square method, wherein m is a scaling coefficient.
Further, in the step S4, the sampling point is sampledScaling substitution calculation, wherein let ∈ ->Where i=1, 2,3, …, (1+k) N is substituted into the function Y (x) i )=a 0 +a 1 x i +a 2 x i 2 +…+a 6 x i 6 Obtaining a displacement dataset +.>
Further, a method for a controller or meter to collect analog displacement.
According to the polynomial fitting-based oil pumping unit indicator diagram acquisition method, a curve of oil pumping unit displacement with respect to time is fitted through least squares by using four or more polynomials, and direct fitting or piecewise fitting is performed according to the performance of an actual embedded platform. And generating a new indicator diagram based on the fitted displacement curve and combining the new indicator diagram with the measured load value. Compared with the traditional smoothing method, the method has better effect, can effectively ensure the monotonicity of the displacement of each stroke up and down, and greatly improves the effective rate of collecting the indicator diagram by the RTU or the instrument of the wellhead controller of the oil field. The method is simple and efficient, and the stability and accuracy of the acquired displacement data are improved well.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
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The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 is a flow chart of a method for acquiring an indicator diagram of a pumping unit based on polynomial fitting according to an embodiment of the present invention;
FIG. 2 is an original diagram;
FIG. 3 is a graph of fitted data versus raw data according to an embodiment of the present invention;
FIG. 4 is a graph comparing fitted displacement data with raw data according to an embodiment of the present invention;
FIG. 5 is a comparison of optimized diagram data versus original diagram data, according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
The invention provides a polynomial fitting-based oil pumping unit indicator diagram acquisition method, which is used as an optimization method of an oil pumping unit indicator diagram.
As shown in fig. 1, the method for collecting the indicator diagram of the pumping unit based on polynomial fitting in the embodiment of the invention comprises the following steps:
step S1, the wellhead controller RTU collects N point set load displacement original data according to the fixed interval of the stroke cycle, and reorganizes the indicator diagram data of the bottom dead center of the original data (S) i ,F i ) The method comprises the steps of carrying out a first treatment on the surface of the Wherein { i|i.epsilon.1, 2,3, …, N }, S i Representing the displacement value of the i-th point, F i The load value at the i-th point is indicated. In the embodiment of the invention, the range of N points is 200 to 250 points, and S is adopted at the same time i The lowest point reorganizes the work diagram data.
Specifically, load and displacement N point data are acquired at regular intervals during the stroke period. Then, according to the displacement minimum point, the indicator diagram data are recombined to form a data set (S i ,F i ) Wherein { i|i ε 1,2,3, …, N }, S i Representing the displacement value of the i-th point, F i The load value at the i-th point is indicated. S is S i When i is 1, the pumping unit is at the bottom dead center, and S is increased along with the increase of i i Gradually increasing to the top dead center displacement value, and then i increases, S i Gradually decreasing, at i=n, the displacement reaches a minimum again.
Step S2, carrying out data enhancement on the displacement data points recombined in the step S1, and expanding the data points into (1+k) N point data sets S new 。
Specifically, enhancing the original data includes:
for displacement S of indicator diagram i Data enhancement is performed. Increasing displacement data S i To N + = (1+k) N, noted as new displacement dataset S new WhereinThe increasing mode is as follows:
step S3, performing n times of polynomial fitting on the data in the step S2,calculating polynomial coefficients a 0 ,a 1 …a n To obtain Y (x) i ) Polynomial functions.
Specifically, a fourth-order and above polynomial is employed based on least squares fitting, wherein for the dataset S new In x i As a function of the amount of the independent variable,is a dependent variable, wherein->And (3) performing polynomial fitting for n times by adopting a least square method, wherein m is a scaling coefficient.
Taking 6 th degree polynomial as an example, a polynomial function Y (x i )=a 0 +a 1 x i +a 2 x i 2 +…+a 6 x i 6 . Calculating coefficient a 0 ,a 1 …a 6 The formula is as follows:
wherein N is + Representing the enhanced data set S of step S2 new Points.
Step S4, carrying out x on the function obtained in the step S3 i Substituting calculation to obtain new displacement data set
Specifically, in step S4, the sampling point is sampledScaling substitution calculation, wherein let ∈ ->Where i=1, 2,3, …, (1+k) N is substituted into the function Y (x) i )=a 0 +a 1 x i +a 2 x i 2 +…+a 6 x i 6 Obtaining a displacement dataset +.>
Step S5, generating a new indicator diagram by using the step S4And the enhanced data is removed therefrom and the data is transmitted,recombination F i Form new N point indicator diagram data +.>
The polynomial fitting-based oil pumping unit indicator diagram acquisition method is used for acquiring analog displacement by a controller or an instrument, and unified specification is carried out on the passing content of each required content setting.
The method for acquiring the indicator diagram of the oil pumping unit based on polynomial fitting is described below with reference to specific embodiments.
1) The original data of the indicator diagram is shown in fig. 2. In fig. 2, the number of displacement points of the indicator diagram is 200 points.
2) Let k=0.25, the new data set after expansion is obtained, the data set length is 250.
3) Let m be 100, with { x|x= 0.01,0.02,0.03,., 2.5} as an argument, with data set S new Polynomial fitting of degree 6 by least square method is performed for dependent variables to obtain a fitting function Y (x i ) The polynomial equation coefficient is a 0 =33.2618,a 1 =-245.1826,a 2 =277.5295,a 3 =1202.06,a 4 =-1618.9906,a 5 =672.5756,a 6 = -91.4594. Substituting { x|x= 0.01,0.02,0.03,..2.5 } into Y (x i )=a 0 +a 1 x i +a 2 x i 2 +…+a 6 x i 6 Obtaining a displacement datasetAs shown in fig. 3. Wherein curve A is data set S new The method comprises the steps of carrying out a first treatment on the surface of the Curve B is the displacement dataset +.>
4) From the slaveIn the step (c), the enhancement part data is removed, and new 200-point displacement data consisting of 26 th point and 225 th point is taken as shown in fig. 4.
5) FIG. 5 is a new indicator diagram curve B formed by taking the data of FIG. 4 as an abscissa and the load as an ordinate, and compared with the original indicator diagram A, the optimized curve effectively removes burrs in displacement and improves the collection efficiency of the effective indicator diagram.
According to the polynomial fitting-based oil pumping unit indicator diagram acquisition method, a curve of oil pumping unit displacement with respect to time is fitted through least squares by using four or more polynomials, and direct fitting or piecewise fitting is performed according to the performance of an actual embedded platform. And generating a new indicator diagram based on the fitted displacement curve and combining the new indicator diagram with the measured load value. Compared with the traditional smoothing method, the method has better effect, can effectively ensure the monotonicity of the displacement of each stroke up and down, and greatly improves the effective rate of collecting the indicator diagram by the RTU or the instrument of the wellhead controller of the oil field. The method is simple and efficient, and the stability and accuracy of the acquired displacement data are improved well.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (5)
1. The method for collecting the indicator diagram of the oil pumping unit based on polynomial fitting is characterized by comprising the following steps of:
step S1, the wellhead controller RTU collects N point set load displacement original data according to the fixed interval of the stroke cycle, and reorganizes the indicator diagram data of the bottom dead center of the original data (S) i ,F i ) The method comprises the steps of carrying out a first treatment on the surface of the Wherein { i|i.epsilon.1, 2,3, …, N }, S i Representing the displacement value of the i-th point, F i A load value representing the i-th point;
step S2, carrying out data enhancement on the displacement data points recombined in the step S1, and expanding the data points into (1+k) N point data sets S new The method comprises the steps of carrying out a first treatment on the surface of the Enhancement to the original data, comprising:
for displacement S of indicator diagram i Data enhancement and increase of displacement data S i To N + = (1+k) N, noted as new displacement dataset S new WhereinThe increasing mode is as follows:
step S3, performing polynomial fitting for n times on the data in the step S2, and calculating a polynomial coefficient a 0 ,a 1 …a n To obtain Y (x) i ) A polynomial function;
step S4, carrying out x on the function obtained in the step S3 i Substitution calculationDeriving a new displacement dataset
2. The method for collecting indicator diagram of oil pumping unit based on polynomial fitting according to claim 1, wherein in step S1, the range of N points is 200-250 points, and S is used at the same time i The lowest point reorganizes the work diagram data.
3. The method for acquiring pumping unit indicator diagram based on polynomial fitting according to claim 1, wherein in the step S3, a polynomial of four times and more is adopted, and the method is based on least square fitting, wherein for the data set S new In x i As a function of the amount of the independent variable,is a dependent variable, wherein->And (3) performing polynomial fitting for n times by adopting a least square method, wherein m is a scaling coefficient.
4. The method for collecting indicator diagram of pumping unit based on polynomial fitting according to claim 1, wherein in step S4, the sampling points are sampledScaling substitution calculation, wherein let ∈ ->Where i= 1,2,3, …, (1+k) N is substituted into the function Y (x) i )=a 0 +a 1 x i +a 2 x i 2 +…+a 6 x i 6 Obtaining a displacement dataset +.>
5. The polynomial fitting based method for acquiring an indicator diagram of a pumping unit of claim 1, wherein the method is used for a controller or a meter to acquire analog displacement.
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US9715480B1 (en) * | 2011-06-24 | 2017-07-25 | United States Of America As Represented By Secretary Of The Navy | Method for analytical reconstruction of digital signals via stitched polynomial fitting |
CN108805215A (en) * | 2018-06-19 | 2018-11-13 | 东北大学 | Based on the Dlagnosis of Sucker Rod Pumping Well dynamic liquid level flexible measurement method for improving drosophila algorithm |
CN108915668A (en) * | 2018-07-17 | 2018-11-30 | 东北大学 | A kind of Diagnosing The Faults of Sucker Rod Pumping System method based on gray level co-occurrence matrixes |
CN110185437A (en) * | 2019-07-22 | 2019-08-30 | 南京南大数字科技有限责任公司 | A kind of indicator card acquisition method suitable for low jig frequency frequency conversion oil well |
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Publication number | Priority date | Publication date | Assignee | Title |
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US9715480B1 (en) * | 2011-06-24 | 2017-07-25 | United States Of America As Represented By Secretary Of The Navy | Method for analytical reconstruction of digital signals via stitched polynomial fitting |
CN103899300A (en) * | 2014-03-25 | 2014-07-02 | 中国石油天然气股份有限公司 | Two-flow well testing analysis method and system based on indicator diagram |
CN108805215A (en) * | 2018-06-19 | 2018-11-13 | 东北大学 | Based on the Dlagnosis of Sucker Rod Pumping Well dynamic liquid level flexible measurement method for improving drosophila algorithm |
CN108915668A (en) * | 2018-07-17 | 2018-11-30 | 东北大学 | A kind of Diagnosing The Faults of Sucker Rod Pumping System method based on gray level co-occurrence matrixes |
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