Using the multi-component induction logging data to evaluate the geometric parameters of the hydraulic fracture

Abstract

Hydraulic fracturing technology can effectively improve the seepage capacity of low-porosity and -permeability reservoirs. Geometric parameters evaluation (height, aperture and length) of hydraulic fracture is essential at different stages of fracturing. This paper presents a new method to evaluate the three parameters of small-scale fractures by multi-component induction logging based on numerical simulations. First, the model of calculation of the induced electric field with vertical hydraulic fractures is established using a three-dimensional finite element method (3D FEM), and the algorithm is verified correctly by comparing it with the analytical solution. Five coil systems of xx, xz, yy, yz and zz that are sensitive to the geometric parameters of the fracture are determined. The relationships between the geometric parameters of the fracture and the measurement signals of five coils are then investigated. The results show that the length and aperture of the fracture have a power exponent relationship with the measurement voltage, while the height parameter is closely related to the logging curves. Based on the relationships, the calculation models of the geometric parameters are established and the applicable range of it is analyzed. It is demonstrated that the complete characterization of fracture geometric can be realized by combining multi-spacing and multi-coil systems. Finally, the influence of the borehole and surrounding formation on the measurements is also considered, and the results indicate that the resistivity of the formation has less influence on the signals than the resistivity of the mud. Compared to the current instrument, the new method can evaluate all three geometric parameters of the hydraulic fracture.