基于地震道多参数反演的岩性转换方法及其应用

Lithologic Conversion Method and Its Application Based on Seismic Trace Multi-parameter Inversion

利用地震数据来描述地层岩性特性,从而解决地下的岩性划分问题,是地球物理反演技术发展的目标。利用测井曲线进行常规岩性反演得到的波阻抗等数据体,仅能间接地反映目标区域的岩性分布情况。多参数反演技术利用地震数据的解释层位为控制手段,以测井曲线为出发点进行外推内插,并通过主组分分析形成初始地质模型,然后进行模型估算,最终得到波阻抗、伽马、电阻率等多参数数据体。利用阈值自动分层方法,依据物性与岩性的相关性,确定单个或多个参数的阈值对多参数体进行岩性转换。渭北平原某煤田的三维地震多参数数据体岩性转换实例表明,多参数岩性反演和基于阈值的岩性转换方法具有较好的适用性,其反演后的界面形态对应较好,单井岩性与转换后的岩性吻合度较高。

Using seismic data to describe lithologic characteristics of strata and so to solve underground lithologic classification is the purpose of geophysical inversion technology. The wave impedance and other data volumes from logging traces conventional lithologic inversion can only indirectly reflect lithologic distribution in target area. The multi-parameter inversion technology uses seismic data interpreted horizons as the control means, carries out extrapolation and interpolation start from logging traces, to form geological model through principal component analysis, then model estimation, finally obtains multi-parameter data volumes of wave impedance, gamma and resistivity etc. Through threshold automatic layering, on the basis of correlativity between physical property and lithology, to deter-mine thresholds of single or multiple parameters carry out lithologic conversion of multi-parameter volumes. A case study of 3D seismic multi-parameter data volume lithologic conversion in a Weibei Plain coalfield has shown that the multi-parameter lithologic inversion and threshold based lithologic conversion have better applicability, the interface configurations after inversion have better correspondence and rather perfect matching rate between individual well lithology and converted lithology.