Method for determining seismic anisotropy
AssigneeBaker Hughes Incorporated
InventorsXiao Ming Tang, Vladimir Dubinsky, Yibing Zheng
Life of this patent
Estimating the term…
Abstract
The method disclosed is useful for estimating anisotropic properties of an earth formation. The method includes extracting travel time values of components of the acoustic wave induced from a downhole tool and reflected from a boundary bed formation. The method further includes obtaining a travel time ratio of the wave components and using the travel time ratio to estimate the anisotropic properties of the formation.
Claims12
A method of analyzing signal data reflected from a bed boundary comprising:
- obtaining travel time data of a first component of the reflected signal data that is selected from the list consisting of a vertical shear wave component, a horizontal shear wave component, and a compressional wave component;
- obtaining travel time data of a second component of the reflected signal data;
- taking the ratio of said travel time data of the first and second components;
- using the ratio to estimate a formation anisotropic property that is selected from the list consisting of P-wave anisotropy, S-wave anisotropy, a difference parameter, and combinations thereof;
- and
- extracting a horizontal shear wave component with the following relationship:
- SH=XX·cos2 α+(XY+YX)·sin α cos α+YY·sin2 α.
A method of analyzing a subterranean formation comprising:
- traversing a downhole tool within a wellbore, wherein the tool comprises a signal transmitter and a reflected signal receiver and wherein a bed boundary is within the subterranean formation;
- inducing a signal into the formation with the transmitter wherein the signal reflects from the bed boundary to create a reflected signal;
- recording the reflected signal with the receiver;
- obtaining travel time information about components of the reflected signal that are selected from the list consisting of a vertical shear wave component, a horizontal shear wave component, and a compressional wave component;
- estimating anisotropic properties that are selected from the list consisting of P-wave anisotropy, S-wave anisotropy, a difference parameter, and combinations thereof of the subterranean formation based on a ratio of the reflected signal component travel times;
- and
- extracting a horizontal shear wave component with a relationship selected from the list consisting of SH=XX·cos2 α+(XY+YX)·sin α cos α+YYsin2 α and qSV=XX·sin2 α−(XY+YX)·sin α cos α+YY·cos2 α.
A method of analyzing signal data reflected from a bed boundary comprising:
- obtaining travel time data of a first component of the reflected signal data that is selected from the list consisting of a vertical shear wave component, a horizontal shear wave component, and a compressional wave component;
- obtaining travel time data of a second component of the reflected signal data;
- taking the ratio of said travel time data of the first and second components;
- using the ratio to estimate a formation anisotropic property that is selected from the list consisting of P-wave anisotropy, S-wave anisotropy, a difference parameter, and combinations thereof;
- and
- extracting a vertical shear wave component with the following relationship:
- qSV=XX·sin2 α−(XY+YX)·sin α cos α+YY·cos2 α.
Dependencies are inferred from the claim text.