基于叠前AVO数据的波形指示反演预测煤体结构

Prediction of coal body structure by waveform indication inversion based on prestack AVO data

煤体结构是煤层气有利区带评价优选及影响勘探开发成效的关键因素。目前主要基于煤心和测井判定煤体结构类型,基于地震资料预测三维空间煤体结构类型仍处于探索阶段。针对沁水盆地M区块,首先根据井中取心直接鉴定的煤体结构类型作为有效的定性依据;然后利用岩石物理分析技术,优选剪切模量μ和密度ρ的乘积得到的弹性参数μρ作为识别煤体结构类型的敏感弹性参数;再基于包含叠前AVO信息的地震数据,通过波形指示反演技术预测μρ体;最后根据原生煤与构造煤的μρ值域差异,预测原生煤与构造煤的空间分布。该区预测结果符合地质规律,且与实钻井吻合程度高达82%,能有效指导生产实践。

The coal body structure is the key factor to evaluate and optimize favorable zones of coalbed methane,and it can affect the exploration and development of the coalbed methane.At present,the structure type of a coal body is mainly determined based on coal core and well logging,and the threedimensional spatial prediction for the structure type of the coal body based on seismic data is still in the exploration stage.This paper studies a block in Qinshui Basin.Firstly,the structure type of the coal body directly identified by borehole coring is taken as an effective qualitative basis,and then the Lame coefficient μρ is selected as the sensitive elastic parameter for identifying the structure type of the coal body by using the petro-physical analysis technology.In addition,the seismic data including prestack AVO information is innovated to predict the Lame coefficient μρ body through waveform indication inversion technology.Finally,according to the μρ value range difference between primary coal and structural coal,the distribution law of primary coal and structural coal is predicted.The prediction results in this research area conform to the geological law,and its coincidence degree with the actual drilling is as high as 82%.Therefore,the research results can effectively guide production and practice.