消除影响压实趋势线地质因素的方法--以莺歌海盆地为例

莺歌海盆地第四系和上第三系地层内除异常压力和压实作用外,影响声波时差的因素主要有岩性变化、成岩胶结作用、地层含天然气及裂缝的存在。这些因素在地层中往往同时存在,难以区分和辨识。借用地震处理过程中多道曲线叠合以增强信噪比的思路,通过局部区块上数口井声波时差压实曲线的叠合处理,反映地层孔隙特征的信息量得到增强,是可避开或消除影响声波速度地质因素的一种有效方法。进一步将这种方法移植到地震速度谱资料的处理中,获得的压力预测结果得到钻井实测压力的证实。

A Method for Eliminating Geology Factors of Affecting Compaction Trendline: an example from Yinggehai Basin

In the Quaternary formation and Upper-Tertiary formation of Yinggehai Basin, except for abnormal pressure and compaction, there are mainly four factors affecting acoustic time, which are lithology variation, cementation, gas in the formation and crack. They usually co-exist and are difficult to distinguish. According to the ideology of seismic processing, i.e., pre-stack noise attenuation/signal enhancement, we superpose multi-wells' acoustic time data of the same local region. In result, the information of reflecting pore characters enhances. It is an effective method to avoid other factors to disturb acoustic velocity. Furthermore, applying this method in processing velocity spectra, the predicted result of the formation pressure conforms to the measured pressure during drilling.