Numerical simulation of high-resolution azimuthal resistivity laterolog response in fractured reservoirs

Abstract

The high-resolution azimuthal resistivity laterolog response in a fractured formation was numerically simulated using a three-dimensional finite element method. Simulation results show that the azimuthal resistivity is determined by fracture dipping as well as dipping direction, while the amplitude differences between deep and shallow laterolog resistivities are mainly controlled by the former. A linear relationship exists between the corrected apparent conductivities and fracture aperture. With the same fracture aperture, the deep and shallow laterolog resistivities present small values with negative separations for low-angle fractures, while azimuthal resistivities have large variations with positive separations for high-angle fractures that intersect the borehole. For dipping fractures, the variation of the azimuthal resistivity becomes larger when the fracture aperture increases. In addition, for high-angle fractures far from the borehole, a negative separation between the deep and shallow resistivities exists when fracture aperture is large as well as high resistivity contrast exists between bedrock and fracture fluid. The decreasing amplitude of dual laterolog resistivity can indicate the aperture of low-angle fractures, and the variation of the deep azimuthal resistivity can give information of the aperture of high-angle fractures and their position relative to the borehole.

Numerical Simulation Study on the Influence of Cracks in a Full-Size Core on the Resistivity Measurement Response

“…Their conclusions, supported by comparisons with actual data, yielded significant results. Deng et al [22] numerically simulated the lateral response of high-resolution azimuthal resistivity in fractured strata, linking azimuthal resistivity to fracture tilt and orientation and providing essential insights for logging interpretation in fractured reservoirs. With advancements in logging technologies, follow-drill logging has gained traction.…”

Numerical simulation and dimension reduction analysis of electromagnetic logging while drilling of horizontal wells in complex structures

“…A fast and accurate EM LWD modeling algorithm is required for the pre-drilling forward simulation, the real-time inversion and the post-drilling evaluation in directional wells (Tan et al 2012;Shao et al 2013;Wang et al 2019). The simulation of EM LWD in HA/HZ wells is essentially a 3D modeling problem (Deng et al 2010(Deng et al , 2015Zhang et al 2019a, b). A variety of accurate 3D EM LWD modeling algorithms, e.g., finite difference method, finite element method and finite volume method (Gao et al 2010;Rumpf et al 2014;Zhang et al 2019a, b), are therefore developed to address the 3D problem associated with tool structures, borehole and mud invasion.…”