Detection and measure of the shear‐wave birefringence from vertical seismic data: Theory and applications

Abstract

An original method is presented that allows us to measure the local shear-wave birefringence properties over any depth interval. It requires the acquisition of two shear-wave vertical seismic profiles (VSPs), each with different initial polarizations of the shear wave. The method is based on the estimation of a two by two matrix (called the propagator matrix) that represents a linear operator between two states of polarization. No information is required about layering above the zone of interest (in particular, about the weathering zone). If these two states of polarization correspond to the direct downgoing shear wave at two different depths z 1 and z2, the operator represents the transmission properties between the two depths. Under the previous hypothesis, this operator is independent of the source polarization and can be accurately estimated by a least-squares method in the frequency domain. Physically, this operator is a multicomponent deconvolution, whose column vectors represent the state of polarizations at a depth Z2 for two linear and INTRODUCTION

Estimation of stress and geomechanical properties using 3D seismic data

“…Since elastic information is derivable from seismic data via AVO inversion, then the in-situ stress state can be estimated from anywhere where seismic waves have intersected the rocks at a wide (>40°) angle. Furthermore, the anisotropic stress equations of Iversen (1995) can be recast using parameters from linear slip theory (Schoenberg and Sayers, 1995), which can be derived from wide-angle, wide-azimuth, 3D seismic data (e.g., Lefeuvre et al, 1992;Varela et al, 2009), as shown here.…”

Integrated Reservoir Characterization: Beyond Tomography

“…Shear and compressional vibrators were used, with a far offset vertical vibrator used to provide signals for orientation of the three component downhole sonde. These data were then analyzed for the presence of shear wave splitting using the propagator matrix technique of Lefeuvre et al (1992).…”

Data‐matrix asymmetry and polarization changes from multicomponent surface seismics

“…This has been observed in both multicomponent seismic reflection data (Squires et al, 1989;Lewis et al, 1991), and vertical seismic profiles (VSPs) (Winterstein and Meadows, 1991). Although most processing techniques designed for multicomponent VSPs have taken into account polarization changes (e.g., Winterstein and Meadows, 1991;Lefeuvre et al, 1992;Zeng and MacBeth, 1993a), those designed for multicomponent seismic reflection data often assume constant polarization direction (e.g., Alford, 1986;Thomsen, 1988;Li and Crampin, 1993a).…”

“…The polarization direction of the leading split shear wave may give information about the orientation of in-situ stresses, and these stresses strongly affect several reservoir characteristics related to drilling, simulation and production (Bruno and Winterstein, 1994). In recent years, many processing techniques have been developed to estimate and interpret this polarization azimuth from recorded multicomponent seismic data (e.g., Alford, 1986;Thomsen, 1988;Winterstein and Meadows, 1991;Li and Crampin, 1993a;Lefeuvre et al, 1992;Zeng and MacBeth, 1993a, b;MacBeth et al, 1994). The polarization azimuth of the leading split shear wave, as related to the direction of the maximum in-situ stress, may vary both laterally with structural location and vertically with depth due to material properties, stratigraphy, bedding, and faults (Warpinski and Teufel, 1991).…”