Research On Adaptive Technology Based On Dynamic Inversion Of Electric Indicator Diagram For CBM Wells

This project has been supported by the major national oil-gas science and technology projects: large oil-gas fields and CBM development "research and application demonstration of drainage adaptive control technology based on wellbore flow field".The article is based on the characteristics of the drainage equipment,aiming at the problem of inaccurate and discontinuous measurement of bottom hole flowing pressure in CBM wells.Through dynamic analysis,a mathematical model for calculating bottom-hole flow pressure based on dynamic inversion electrodynamometer diagram is established by optimization algorithm.It measured input electricity Parameters of drainage and mining equipment,used the established dynamic model,got Bottom-hole flow pressure of drainage.Furthermore,an adaptive control system for drainage and mining is constructed,the problem of discontinuous calibration in bottom hole flowing pressure measurement is solved.In order to realize the continuous,stable and real-time control of CBM drainage and production,it lays a foundation for stable and high production of CBM.Firstly,this paper analyses and calculates the motion and force of pumps,and calculates the suspension motion parameters and the solving formulas of each torque.To obtain differential equation of motion of the mechanical system,it established the equivalent dynamic model of the mechanical system of pumping unit.Analyze the real motion law of the pumping unit is order to determine the real crank speed by using the idea of iteration.The paper analyzed mechanical characteristics of different motors and carrying out the balance analysis of pumps under the condition of crank real motion based on motor driving characteristics.Then,the paper starts from the dynamics model of pumping unit,analies the actual well condition,tests the power of motor,calculating the crank power according to the equivalent dynamics model,compares the calculated crank power with the test power,takes the minimum error of test power and calculation power as the objective function to obtain the optimal indicator diagram by using Powell optimization algorithm.Secondly,the paper carries out the significance analysis of the influencing factor of indicator diagram test accuracy.The results show that system efficiency,motor characteristics and system inertia have direct effects,and different factors have significant effects on the eigenvalues of indicator diagrams.It established the significant factors of system parameters influencing the measurement accuracy,designed orthogonal experiments,quantifying the sensitivity of the influencing factors of the indicator diagram by variance analysis,and judged the order of the influencing factors on the characteristic values of the indicator diagram and the relationship between the influencing factors.In order to realize continuous and reliable testing of drainage equipment,by realizing the self-correction of parameters and improving the accuracy of testing.Thirdly,the paper analies the working process of pumps,analysis force of Underground Suspension Load.Establishment of Mathematical Model for Calculating Bottom Flow Pressure Based on Indicator Diagram,Field test results show that the model meets the requirements of field test accuracy.Finally,the self-adaptive control system of electrodynamometer diagram for drainage and recovery parameters of CBM wells is compiled by using MATLAB.The functions includes data acquisition,balance analysis,indicator diagram inversion calculation,bottom hole flow pressure calculation and stroke adjustment.It can effectively control the exploitation of CBM and improve the efficiency of the exploitation of CBM.