Westerngeco L.l.p.

Keshan Zou

Jianchun Dai

Haibin Xu

Adam P Koesoemadinata

Andrew E Hannan

Method for subsurface exploration. In one implementation, the method may include receiving a gamma value at a subsurface interface, wherein the gamma value is a ratio of Vp/Vs at the subsurface interface. Vp is the average P wave velocity and Vs is the average S wave velocity. The method may further include receiving a converted wave reflection coefficient at the subsurface interface. The converted wave reflection coefficient is a function of a density contrast at the subsurface interface and a shear velocity contrast at the subsurface interface. The method may further include determining a P wave incident angle such that the converted wave reflection coefficient is a function of substantially only the density contrast at the P wave incident angle. The P wave incident angle is referred to herein as &#x3b8;. The method may further include calculating the density contrast based on the converted wave reflection coefficient at &#x3b8;.

Determining density contrast at subsurface interface

A method for generating an average gamma factor for recorded PS data and recorded PP data. The method includes mapping one or more arrival times of the recorded PS data onto one or more expected arrival times of the recorded PP data using an estimated average gamma factor, identifying one or more corresponding pairs of events in the recorded PS data and the recorded PP data using forward modeling, applying geophysical reasoning on the corresponding pairs of events and generating the average gamma factor.

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Missouri City, TX, United States of America

Keshan Zou