Research On Pseudo-Random Electromagnetic Method For Interwell Reservoir Detection

At present,a large number of oil reserves exist in underground reservoirs in the form of residual oil.Therefore,in order to improve oil recovery,it is necessary to improve the recovery of residual oil.Inter-well is a main existing area of residual oil,so the exploration of inter-well reservoirs is of great significance.In view of this,this paper conducts basic research on pseudo-random signal electromagnetic method for inter-well reservoir detection in order to improve the recovery rate of remaining oil.Firstly,the general scheme of cross-well prospecting by pseudo-random electromagnetic method is given,and the principle of pseudo-random signal correlation identification technology based on Wiener-Hough equation is analyzed.Secondly,the characteristics of several common pseudo-random sequences are analyzed,and m-sequence is selected as the input signal of the system studied in this paper.The generation method,properties and parameter selection of m-sequence are analyzed and studied.Thirdly,based on the line source theory,the cross-well detection model is established by COMSOL Multiphysics software.The uniform and non-uniform cross-well detection model is given respectively,and the feasibility of the model is verified.Then,the potential distribution of the uniform cross-well detection model and its influence by the position of the receiving electrode are studied based on the excitation source m sequence,and the conductivity of the anomalous body is also studied.The influence of variation of burial depth and thickness on the potential distribution of non-uniform inter-well detection model is analyzed.Finally,based on pseudo-random correlation identification technology,the correlation identification of impulse response of open-hole inter-well detection model,uniform inter-well detection model and non-uniform inter-well detection model is carried out,and the difference of impulse response is analyzed.The results show that the pseudo-random signal electromagnetic method can effectively detect the inter-well reservoirs and lay theoretical foundation for improving the recovery of remaining oil.