The Research On Electromagnetic Response Characteristics Of Cross-hole Formation Resistivity

China’s oil recovering rate is about30%~40%, and a large number of crude oil is theremaining oil left in the ground. Crosswell is the major regions for residual oildistribution.This article studies on the formation resistivity characteristics of electromagneticresponse to detect the problems for Crosswell remaining oil distribution. Crosswell resistivitymeasurement is very important for improving the recovering rate to detect crosswell remainingoil as a metal-cased hole formation resistivity logging methods.In the first place, a brief introduction of research status of electromagnetic logging waslaunched both at home and aboard. Following this, both the basic theory and the keytechnology of transient electromagnetic defect detection were studied. On this basis, beginningwith maxwell’s equations and the introduction of vector, it will change the problem of themaxwell’s equation into a solution of vector helmholtz equation. By means of electromagneticanalysis software COMSOL, Set up different Cross-Wells simulation models of longitudinaland radial direction respectively, and get the numerical solutions of cross-well electromagneticfield of vertical line source under different models. Uniform space, homogeneous half space,and all three layer model of electromagnetic field on the response characteristics wereanalyzed. Respectively in three layers of the earth models, for example, changing the emissioncurrent, the transmitting frequency, the line source system parameters and the parameters suchas resistivity well, it will get electromagnetic field numerical simulation of the response tovarious parameters response characteristics of the electromagnetic field. Then the inversionmodel for crosswell formation resistivity imaging and its algorithm are studied, and theobjective function and specific inversion iteration algorithm are given. Moreover, adopting theobject-oriented method, this paper is designed and developed the crosswell resistivity imagingsystem, and completed the formation resistivity imaging display.Finally, the conclusions of this paper are given and the suggestion for further research isprovided.