primary assumption in most problems of elasticity theory in petroleum geophysics is that the elastic media is isotropic. laboratory experiments confirmed that most rocks are anisotropic. if in one medium, properties vary with directions, it is named as anisotropic. knowledge about anisotropy reduces risk and cost of hydrocarbon production. in the present study, anisotropy of a carbonate reservo...

Anisotropy in shales is becoming an important issue in exploration and reservoir geophysics. In this study, the crystallographic preferred orientation of clay platelets that contributes to elastic anisotropy was determined quantitatively by hard monochromatic X-ray synchrotron diffraction in two different shales from drillholes off the coast of Nigeria. To analyze complicated diffraction images...

Geophysical imaging provides a unique perspective on metasomatism, because it allows the present day fluid distribution in the Earth’s crust and upper mantle to be mapped. This is in contrast to geological studies that investigate midcrustal rocks have been exhumed and fluids associated with metasomatism are absent. The primary geophysical methods that can be used are (a) electromagnetic method...

S U M M A R Y We examine seismic velocity and anisotropy at the interface between the Australian and the subducting Pacific Plate in southern North Island, New Zealand using receiver functions from teleseismic earthquakes recorded on two L-shaped seismic arrays. IRIS station SNZO makes up the corner of the southern array. Velocity models are tested with a ray theoretical method that allows both...

This article describes a parallel implementation of a ray tracing algorithm in a heterogeneous anisotropic geological medium. The shortest path method, which was used for calculations, can give ray path and travel time of seismic wave propagation even for a random and discontinuous velocity field. The high precision required in such calculations was obtained by employing a dense computational g...

A model is presented that simulates anisotropy development in a subducting slab from the upper–lower mantle boundary (661 km) to the core–mantle boundary (2891 km). Two phases are considered: orthorhombic MgSiO3-perovskite and cubic magnesiowuestite (Mg,Fe)O. Single crystal elastic properties at mantle conditions are obtained from existing density functional theory calculations and quasiharmoni...

A marine VSP is designed to estimate the orientation and density of fracturing within a gas-producing dolomite layer in the southern North Sea. The overburden anisotropy is firstly estimated by analysing shear waves converted at or just below the sea-bed, from air-gun sources at four fixed offset azimuths. Full-wave modelling helps confirm that the background has no more than 3% vertical birefr...