利用叠前克希霍夫积分偏移提取纵横波进行油气检测

The extraction of P-wave and S-wave for hydrocarbon detection using prestack Kirchhoff integral migration

新疆石油局地球物理研究所,乌鲁木齐 830011

Institute of Geophysics, Xinjiang Petroleum Administration, Urumqi 830011

纵波(υ_p)通过岩石基质和孔隙流体传播,而横波(υ_s)只通过岩石基质传播。当地层含气或油时,υ_p发生变化,υ_s变化不大。利用υ_p、υ_s资料联合解释,可提高可靠性。当前野外地震勘探主要是纵波勘探,如何从常规剖面中提取横波,是当今研究的热点。本文介绍了利用Kirchhoff积分偏移直接从常规地震剖面中提取转换横波,用于烃类检测,并在准噶尔盆地腹部王西沙漠地区获得了成功,为今后的岩性勘探、储层预测、直接找油找气提供了一种新手段。

P-wave propagates through rock matrix and pore fluid while S-wave can only propagatethrough rock matrix. When the strata contain gas or oil,P-wave velocity will change but S-wavevelocity will hardly change. The combmed interpretation using both P-wave and S-wave data canimprove reliability. How to pick up the S-wave from the conventional sections is a hotspot of current research. In the paper. the Kirchhoff integral migration is used to extract the converted S-wave directly from the conventional seismic sections for the hydrocarbon detection. Its applicationin the Shixi desert area of the central Zhunger basin is successful. It provides a new way for theIithology exploration,reservoir prediction and hydrocarbon direct searching.