Study On Numerical Simulation Of Cross-well Electromagnetics And Methods Of Imaging

The development of domestic oil fields has entered middle and late currently,which are mostly water injection wells,there is a lot of residual oil-rich region in the oil layer,due to the cross-well electromagnetic imaging technology can detect the distribution of conductivity between the well region,it can detect residual oil distribution,testing well water vapor dynamic,so the technology is particularly important in the development of oil and gas wells.Compared with electric logging,its detection range is deeper and greater,and it can effectively solve the uneven issues of information type and the information quantum collected between "wells" and "cross-well",fundamentally change the inherent weaknesses of lateral detection capability insufficient of logging technology,improve reservoir description capabilities;and compared to magnetotelluric and ground-borehole electromagnetic method,it has higher imaging accuracy.Therefore,the research on cross-well electromagnetic Simulation and Imaging Methods is quite necessary.This paper based on the theory of current and magnetic sources vector Green function of horizontal layer anisotropy formation,simulated cross-wells electromagnetic response in tilt and layered anisotropic formation by using weakened BCGS algorithm of body integral equations.When simulating the scattered magnetic field generated by three-dimensional anomalies,the stratified anisotropic formation is taken as background formation.The data points are only distributed in anomalous bodies,thus the number of unknowns and the amount of calculation are greatly reduced.The results show that the axial component of the magnetic field is closely related to the inclination angle and the cross-well distance when the wells are inclined,its imaginary part can identify the background formation's interface more accurately when the inclination angle of the receiver well increases.The axial component of the scattered magnetic field is relatively large and is greatly influenced by the background formation's anisotropy,which can be used in detecting the presence of anomalous conductivities.The horizontal component of the scattered magnetic field is much smaller comparing with the total magnetic field,and it is not easy to detect the presence of anomalous conductivities by this component.Different anisotropy can make a great difference on the horizontal component of the total magnetic field,and its real part can be used to identify the background formation's interface accurately.In the inversion process,Born iteration(BIM)inversion will be used for the two-dimensional cross-well electromagnetic inversion theory and achieved good results.The inversion theory can be used to rapid inversion imaging of three-dimensional abnormal electrical conductivity block,inversion results show that can obtain the depth position location of conductivity anomaly block layer accurately and rapidly by Born iteration(BIM)inversion,compared to the position of actual abnormal block,there will be a shift in the horizontal direction.This has profound significance in practical applications of petroleum storage detection,and it provides fast,accurate and reliable references for further study of three-dimensional inversion imaging.