Forward Modeling in Hydraulic Fracture Detection by Means of Electromagnetic Wave Logging While Drilling in Vertical Wells

In order to understand the distribution of oil and gas resources in low permeability reservoirs and better control the productivity of oil and gas wells, it is necessary to systematically study the fractures generated from hydraulic fracturing. Based on the theory of electromagnetic field, an analytical model in homogeneous and isotropic formations was established, then the formation and fracture model of vetical well was established using finite element software. Forward modeling was carried out on the amplitude ratio and phase difference of induced electromotive force between the receiving coils of electromagnetic wave logging tool. The results of the forward modeling showed that: signal amplitude ratio and phase difference around fracture change significantly; phase difference shows an obvious stratification, and there is higher resolution for propped fractures with different heights and different electrical conductivities of proppant. The most sensitive factor is the electrical conductivity of the proppant. A better simulation response was obtained under the source distance of the instrument was 0.25 m and the transmitting frequency was 400 KHz. The above research results indicated that it is feasible to use electromagnetic wave logging while drilling to detect hydraulic fractures in vertical wells. The research conclusions also provided a certain theoretical basis for the detection and evaluation of hydraulic fractures in vertical wells and could thus be applied in similar situations.