MODELING AND ANALYSIS FOR ABNORMAL RESPONSE ON VARIABLE PHYSICAL PARAMETERS BY BOREHOLE-GROUND DC METHOD

To study the influence rules of the surface abnormal response on the variable physical parameters by borehole-ground DC method,we model the abnormal response with the finite element method.The results showed the distribution of the anomalies is clear when the anomalous body lies in the shallow position,and the distribution of the anomalies became unclear with the depth increasing.The surface abnormal response is insensitive to thickness of the anomalous body,but the response is very sensitive to the lateral dimension.All these rules will give some reference and guide to determine the distribution of the residual oil and the position of the water-injection front and the design of instrumental resolution.At the same time,the results laid the foundations for inversion and imaging of borehole-ground DC method.