Research And Application Of Self-optimizing Control Technology For Pre-installed Oil Lifting Process

During the process of oil lifting,due to the pumping rate of the pumping unit being greater than the underground oil seepage rate,it often leads to the phenomenon of "empty pumping" of the pumping unit,resulting in a large waste of electrical energy and economic losses.The conventional post control technology based on platform cloud computing has poor real-time performance and low engineering application value due to factors such as network signal quality and data transmission delay.At the same time,its control algorithm is not intelligent enough to effectively prevent the pumping unit from being in the "empty pumping" state.In response to this issue,this paper combines the actual operating conditions and structural characteristics of the pumping unit system to study the self-optimizing control algorithm for the pre hydraulic lifting process,as well as the soft measurement methods for key parameters such as indicator diagram and dynamic liquid level related to the algorithm.Based on this,a prehydraulic lifting process self-optimizing control device has been developed.The structure and operating principle of the pumping unit system were studied,and the problems that may occur during oil extraction operations were analyzed,the necessity of pre-installed self-optimizing inter pumping control technology for oil wells was clarified,the shortcomings and shortcomings of existing mechanical extraction methods and control methods were pointed out,and the development trend of pre-installed self-optimizing inter pumping control technology for oil wells was studied.The soft measurement methods for important parameters required by the self-optimizing control technology of the front-end oil lifting process were studied.Starting from the electrical parameters of the driving motor,we have established a series of mathematical models,and replaced hardware measurement with software calculation to achieve soft measurement of parameters.Firstly,the measurement method of electrical parameters related to the driving motor supplying energy to the pumping unit was studried;And based on the mechanical parameters of the four link structure of the pumping unit,a mathematical calculation model for the displacement of the donkey head lifting point was established with the inclination angle of the beam as the input.Using the electrical parameters of the driving motor and the inclination angle of the beam as the input,construct a mathematical calculation model for the load of the donkey head suspension point.By identifying the upper and lower dead points,determine the stroke period,and then perform singular value removal and filtering processing on the obtained indicator diagram,thus achieving soft measurement of the ground indicator diagram;At the same time,establish the correlation relationship between the hanging point load and the dynamic liquid level,in order to accurately soft measure the depth of underground dynamic liquid level.The definition and theoretical calculation method of the efficiency of the mechanical production system,as well as the variation law of the liquid level in the wellbore of low permeability and low production oil wells were studied.Based on this theory,we have studied the use of unscented Kalman filtering algorithm to real-time denoise and optimize the estimated liquid production value of oil wells,making the estimated liquid production value of a single well closer to the real value and better grasping the downhole working conditions.The relevant algorithms of self-optimizing control technology for front mounted oil lifting process were studied.Firstly,a self-optimizing algorithm based on the principle of "mountain climbing method" was studied to iteratively optimize the calculation of the start stop time of the pumping unit by comparing the electrical energy consumed during the two working hours before and after,in order to achieve the goal of "air defense pumping".Secondly,the principle of detecting oil well empty pumping based on power integration theory was analyzed.On this basis,a fusion method of empty pumping features based on electrical parameters and polished rod load was studied,and the grey prediction algorithm was applied to the control of oil well empty pumping.Finally,a grey self-optimization control model for oil well empty pumping that integrates electrical parameters and polished rod load was proposed to optimize and match the oil pumping process with the wellbore seepage law,And the feasibility of this method was verified through simulation.The technical implementation of self-optimizing control algorithm for pre-installed oil lifting process was studied.Designed the overall plan of the self-optimizing intelligent pumping measurement and control system for oil production well sites;We have completed the hardware design and software process design of the core intelligent measurement and control unit of the system based on a dual DSP structure,respectively achieving the functions of electrical parameter acquisition,soft measurement of indicator diagram and dynamic liquid level,and grey self-optimization control between oil wells.Finally,experimental verification was conducted on the indicator diagram and dynamic liquid level soft measurement method,as well as the grey self-optimizing control model for oil well pumping that integrates electrical parameters and suspension load.The on-site test results conducted at the First Oil Production Plant of Changqing Oilfield show that the average relative error of the indicator chart soft measurement method proposed in this article is 3.95%,which can accurately and stably achieve online real-time soft measurement indicator charts.The relative error of the dynamic liquid level depth obtained by the dynamic liquid level soft measurement method can be controlled within 10%,which can better reflect the underground working conditions;The proposed grey control algorithm for oil well pumping that integrates electrical parameters and suspension load can dynamically optimize and match the oil pumping process with the wellbore seepage law,achieving supply and drainage coordination.The average efficiency of the mechanical production system has been improved by 4.25%,with an average daily energy saving of 86.5kWh.It can effectively reduce electricity waste,avoid"empty pumping",deeply improve the efficiency of the mechanical production system,and has high practical engineering value.