Grid-characteristic method using Chimera meshes for simulation of elastic waves scattering on geological fractured zones

Abstract

Geological fracture zones play an important role in determining the amount of deposits in oil and gas fields. In practice, for modeling wave scattering in fractured zones, numerical methods are usually used on structured computational meshes to save computational resources. However, these numerical methods can only calculate wave scattering on cracks in the direction of the coordinate axes. To describe more realistic models of fractured fields, numerical methods are used on unstructured computational meshes or structured curvilinear computational meshes, which requires significant computing resources and is critical when solving inverse problems. In this article, we propose a numerical grid-characteristic method using Chimera meshes. In this method, we perform calculations on structured regular computational meshes, superimposing Chimera meshes rotated along the cracks. It is important that the Jacobian of rotation is set analytically, and the rotated computational meshes have a small local size, to save computational resources.