二维地震迭加偏移剖面“二步法偏移”地质解释方法

"Two-step migration" geologic interpretation method of 2D seismic stack migration section

为了解决二维迭加偏移剖面作图中存在的主联测线不能闭合的问题,利用自激自收地震反射波原理在层状均匀介质条件下推导出地下反射点位置与射线路径、目的层视倾角及目的层埋深之间的复杂关系,并计算反射点位置的偏移量及反射点到地面的垂直深度.地质作图可同时利用主测线联络测线,解决了目前二维迭加偏移剖面作图中存在的不能闭合及数据为法线深度等问题.用垂直深度作图,断裂系统联接合理,构造图精度高,构造形态可靠、逼真,可提高钻探成功率.

There is a problem in two-dimensional stack migration profile mapping that the in-line and the cross-line are not closed.The complex relationships between the location of the underground reflection point and ray-path,apparent dip of target stratum and buried depth of target stratum in seismic lines in homogeneous formation are derived on the basis of the principle of the self-stimulating and self-receiving seismic reflection.The relationships can be popularized to stratified medium condition to calculate the offset of the reflection point and the vertical depth of it to the surface.Geological mapping can meanwhile utilize the in-line and the cross-line to obtain the vertical depth of the reflection point to the surface,which solves the problems in two-dimensional stack migration profile mapping that the in-line and the cross-line are not closed and that the obtained data are normal depth.Vertical depth mapping can obtain rationally-linking fault system,high-accuracy structure map,and reliable and lifelike structural configuration.It can also increase the success rate of drilling.