Microlocal analysis of borehole seismic data

TL;DR

This paper uses microlocal analysis to evaluate the potential for reconstructing subsurface sound speed from borehole seismic data, highlighting conditions for artifact-free imaging and limitations in certain geometries.

Contribution

It provides a microlocal analysis framework for borehole seismic data, identifying when accurate reconstruction is possible and characterizing artifacts in different data acquisition geometries.

Findings

Dense array data allows artifact-free reconstruction without caustics.

Walkaway and crosswell geometries produce strong, nonremovable artifacts.

Reconstruction feasibility depends on the background ray geometry and caustic presence.

Abstract

Borehole seismic data is obtained by receivers located in a well, with sources located on the surface or in another well. Using microlocal analysis, we study possible approximate reconstruction via linearized, filtered backprojection of an isotropic sound speed in the subsurface for three types of data sets. The sources may form a dense array on the surface, or be located along a line on the surface (walkaway geometry) or in another borehole (crosswell). We show that for the dense array, reconstruction is feasible, with no artifacts in the absence of caustics in the background ray geometry, and mild artifacts in the presence of fold caustics in a sense that we define. In contrast, the walkaway and crosswell data sets both give rise to strong, nonremovable artifacts.