Research On Diagnosis And Production Calculation Technology Of Rod-Pumped Well Based On Dynamometer Card

At present,the oil field is facing with several challenges as follows: oil production of single well reduces,and the number of well constantly increases;the work site environment of oil field is complex and harsh;the underground condition is complex,and the failure of pumping well occurs frequently.Therefore,it is necessary and urgent to apply a digital information technology to achieve the real-time monitoring of well conditions and automatic production calculation.The analysis of oil well condition and production calculation is the main daily technical management work of oil field,and is the "barometer of oil well" to judge if it works normally.As an important basis for the diagnosis and production calculation,dynamometer card can reflect the working status of oil well.In this paper,it focuses on dynamometer card as the object of study and designs a complete set of pumping well condition analysis and production calculation system.In each step of this system,the technique was studied in details:1.Pre-processing and spectrum analysis of dynamometer card.First,remove the dynamometer card with errors to improve the efficiency and accuracy of calculation of diagram processing.Then,study the de-noising method of dynamometer card,compare the FFT denoising to wavelet denoising in the dynamometer card processing,and apply wavelet denoising as the final choice to process dynamometer card.Finally,extract the noise signal of dynamometer card,calculate the vibration intensity of noise signal,and make a quantization of the vibration and sanding of the dynamometer card.2.Judgment of special working conditions and reduction of pump dynamometer card.First,adopt the area analysis method dynamometer card to analyze the dynamometer card with pre-processing and denoising.Compute the dynamometer card area after the noise reduction processing,compare it to the theory of the dynamometer card area,and define the dynamometer card of the smaller size as the special working condition.Then,study the reduction of pump dynamometer card.According to the information of the rod,oil property,rod wave equation and the damping coefficient,compute the pump dynamometer card.3.The recognition of dynamometer card to classify the pump dynamometer card after reduction.The paper studies the comprehensive diagnosis grading method,that is,adopting the combination of the expert recognition technology and image recognition technology to achieve the recognition of dynamometer card and the diagnosis of well working condition.First,based on the dynamometer card and pump dynamometer card achieved by 1 and 2,respectively,adopt the image recognition technology to recognize the pump dynamometer cards with normal-sized area and make a class discrimination of the pump dynamometer cards.Then,apply the expert recognition to refine the class discrimination to correct the errors in image recognition.4.Quantization of the dynamometer card.Through the dynamometer card recognition technique,the well condition has been diagnosed,and then the next step is to make a quantitative analysis of pumping system.According to the physical meaning of the dynamometer card,make an accurate extraction of valve opening and closing points,compute the effective stroke of plunger,and compute the oil well liquid production with a combination of the diagnosis of working conditions.In addition,make an analysis of the pump efficiency,balance rate,rod stress of the oil well and the efficiency of the system to achieve the analysis of the overall conditions of the oil pumping system.