山区纵、横波联合勘探的资料解释

Data interpretation of joint compressional and shear wave survey in mountainous region

综合利用纵、横波联合勘探资料,不仅有利于寻找地层圈闭、岩性圈闭、裂缝圈闭等非构造油气藏,而且能正确判断岩层中流体的性质、地下岩性变化及裂缝带的分布范围,提高资料解释成果的精度。本文以四川 HBC 地区为例,介绍了横波层位的标定、碳酸盐岩储层的构造解释及天然气富集带的判别等方法。在资料解释中,要特别注意纵、横波振幅比和速度比异常的分析。在HBC 地区的纵、横波振幅比异常和速度比异常多分布于构造的轴部和小鼻褶上。振幅比异常区一般为天然气聚集区,速度比异常多为裂缝发育带的反映。在上述两种异常同时存在的构造部位所布的探井,均取得了很好的钻探效果。

The joint utilization of compressional and shear wave data favours us to dis- cover nonstructural hydrocarbon traps such as stratigraphic trap,lithologie trap,fracture trap,etc.and to ascertain fluid situation in formation,lithologic variation and fracture zone,so that the accuracy of seismic data interpretation is improved greatly.I describe how to determine shear wave horizon,how to inter- prete carbonate reservoir and how to discover gas accumulation zone in HBC area in Sichuan Province.It is very important to pay more attention to analysing the ratio between compressional wave amplitude and shear wave amplitude,and the ratio between compressional wave velccity and shear wave velocity in data interpretation.The amplitude ratio anomaly and the velocity ratio anomaly in HBC area can be usually seen at anticlinal axis areas and small noses.Generally speaking,the amplitude ratio anomaly area reflects gas accumulation and the ve- locity ratio anomaly area exhibits dense fracture zone.Good results have been obtained from exploratory wells in the areas where there occur the two anomalies simultane- ously.