We develop an anisotropic plane-wave migration method based on wavefield extrapolation. In this new scheme, we decompose both source and receiver wavefields into plane waves by delaying shots. For each plane wave, we design a tilted coordinate system whose tilting angle depends on the propagation direction of the plane wave. The wavefield extrapolation is done by an implicit isotropic operator ...

We develop a new 3D wavefield-extrapolation method for a transversely isotropic (TI) medium with a symmetry axis. The wavefield extrapolation is done by an implicit isotropic extrapolation operator with an explicit correction operator. The explicit correction is a 2D convolution operator in the space domain, whose coefficients are estimated by a weighted least-squares method in the Fourier doma...

Constructing the seismic image in vertical time, as opposed to depth, eliminates the inherent ambiguity of resolving the vertical P -wave velocity from surface seismic data in transversely isotropic media with a vertical axis of symmetry (VTI media). By ray tracing in the space-time (x-τ)-domain, a traveltime map is built by interpolating the traveltime information along the rays onto a regular...

The scalar generalized-screen method in isotropic media is extended here to trans-versely isotropic media with a vertical symmetry axis (VTI). Although wave propaga-tion in a transversely isotropic medium is essentially elastic, we introduce an equiv-alent ‘acoustic’ system of equations for the qP-waves which we prove to be accuratefor both the dispersion relation and the po...

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...

Since the work of Postma (1955) and Backus (1962), much is known about elastic constants in vertical transversely isotropic (VTI) media when the anisotropy is due to ne layering of isotropic elastic materials. I review earlier work and then show that the P-wave anisotropy parameter c 11 =c 33 lies in the range 1 4 c 11 =c 33 h + 2i h1=(+ 2)i, when the layers are themselves composed of isotropic...

The main goal is to analyze the influence of cracks on azimuthal variations amplitude. We restrict our investigation a single set vertical, circular, and flat cavities aligned along horizontal axis. Such are embedded in either transversely isotropic background with vertical symmetry axis (VTI) or surroundings. employ effective medium theory obtain orthotropic VTI homogenised medium, respectivel...

Abstract Anisotropies exist in many sedimentary rocks, particularly naturally fractured reservoirs, causing horizontal stress anisotropies. Case studies indicate that when a rock formation contains high dip-angle fractures or factures (e.g. bedding planes), it has very distinguished stresses. In these cases, the conventional isotropic method for estimating stresses may give erroneous results. U...

The paper presents the results of laboratory studies on strength–strain properties shales representing four siltstone-claystone lithostratigraphic units occurring in Baltic Basin. Laboratory a triaxial stress state were conducted as single failure tests cylindrical samples oriented parallel and perpendicular to lamination within rocks. Mutually cut out from same drill core sections order determ...

A general analysis of poroelasticity for vertical transverse isotropy (VTI) shows that four eigenvectors are pure shear modes with no coupling to the pore-fluid mechanics. The remaining two eigenvectors are linear combinations of pure compression and uniaxial shear, both of which are coupled to the fluid mechanics. After reducing the problem to a 2 × 2 system, the analysis shows in a relatively...