Cross-well electromagnetic imaging method based on automatic regularization
Cross-well electromagnetic technology can be used to obtain high-resolution resistivity images between wells,which is of great significance for monitoring formation fluid changes and enhancing oil and gas recovery.In this paper,a resistivity imaging method based on rigorous 2.5-dimensional electromagnetic modeling and inversion is developed using the Gauss-Newton method with a multiplicative cost function and automatic regularization.The regularization parameter is related to the data cost function such that it will be reduced automatically with the data cost function,and stop at the noise level to avoid the overfitting of the data.The tests on stratified formations and formations with abnormal bodies show that the method can achieve accurate resistivity imaging between wells.The cross-well resistivity imaging method is used to invert the electromagnetic data acquired by the newly developed cross-well electromagnetic imaging prototype instrument in Xinan region,and the imaging results are in good agreement with the resistivity curves of two wells,which verifies the effectiveness of the instrument,as well as the cross-well resistivity imaging method.
cross-well electromagnetic imagingmultiplicative cost functionautomatic regularizationGauss Newton method
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