US 2010/0133010 A1 · Anisotropic Depth Velocity Model Estimation Above the Receiver Array in Walkaway or 3D VSP Data

Abstract

A walkaway VSP survey is carried out using a receiver array. Using a vertical VSP survey and arrival times of surface multiples on the walkaway VSP, vertical interval velocities and the anisotropy parameters δ and ε are estimated. This may then be used to process surface seismic data to do a prestack depth migration of surface seismic data and used for interpretation. For multi-azimuthal walkaway or 3D VSP data, we determine two VTI parameters ε and δ for multi-azimuth vertical planes. Then we determine five anisotropic interval parameters that describe P-wave kinematics for orthorhombic layers. These orthorhombic parameters may then be used to process surface seismic data to give a stacked image in true depth and for the interpretation purposes.

Claims18

Dependent claims

A method of evaluating an earth formation, the method comprising:

deploying an array of seismic receivers in a borehole and recording seismic signals in the array of receivers responsive to an activation at least one seismic source on the surface of the earth at least one location offset from the borehole;
estimating, from travel times of seismic waves from the at least one location that have been reflected at an interface in the earth formation and the surface of the earth to the plurality of receivers, a velocity model including velocities of vertically propagating seismic waves in a plurality of intervals, and an anellipticity parameter related to a normal moveout velocity of compressional waves for the plurality of intervals;
and
using the estimated velocity model for producing an image of the earth formation.

1 more element

Dependencies are inferred from the claim text.

Anisotropic Depth Velocity Model Estimation Above the Receiver Array in Walkaway or 3D VSP Data

Life of this patent

Anisotropic Depth Velocity Model Estimation Above the Receiver Array in Walkaway or 3D VSP Data

Life of this patent

Abstract

Claims18