基于测井参数宏观煤岩类型预测及三维地质建模

Macrolithotype prediction and 3D geological modeling based on logging parameters

为实现定量判别宏观煤岩类型分布特征,依据煤层气参数井煤岩描述结果,利用不同宏观煤岩类型在测井响应特征的差异性,建立宏观煤岩类型指数(HMLZ)。通过该判别方法完成SZB区块30口井宏观煤岩类型定量识别及验证,进一步采用随机建模方法实现宏观煤岩类型空间分布特征的三维可视化。结果表明HMLZ>20.0为光亮煤;10.0<HMLZ<20.0为半亮煤;5.5<HMLZ<10.0为半暗煤;HMLZ<5.5为暗淡煤。研究区3号煤层宏观煤岩类型主要为光亮煤和半亮煤,半暗煤次之,暗淡煤不发育。光亮煤平均厚度占比36%;半亮煤平均厚度占比46%,主要分布在区块的北部和南部煤层的中上段;半暗煤主要分布在区块的中部煤层的中下段,平均占15%;暗淡煤零星发育在区块的西南角煤层的底部,厚度较薄,占3%。总体来看,模型能有效地定量评价煤岩类型分布规律,为煤层气开发提供有力支撑。

In order to quantitatively distinguish the distribution characteristics of marcolithotypes,the authors in this research utilized the differences of logging response characteristics of different marcolithotypes to establish the marcolithotypes index HMLZ,according to the coal and rock description results of CBM parameter wells.The quantitative identification and verification of marcolithotypes of 30 wells in SZB block are completed through the discrimination index,and the 3D visualization of the spatial distribution characteristics of macrolithotypes are rea-lized using the stochastic modeling method.The results show that the HMLZ>20.0 is bright coal,and the 10.0<HMLZ<20.0 is semi bright coal.Besides,5.5<HMLZ<10.0 is semi dark coal and the HMLZ<5.5 is dull coal.The macrolithotypes of coal seam 3 in the study area are mainly bright coal and semi bright coal,followed by semi dark coal,and the dull coal is not developed.The average thickness of bright coal accounts for 36%,and the average thickness of semi bright coal accounts for 46%,which is mainly distributed in the middle and upper sections of coal seams in the north and south of the block.Semi dark coal is mainly distributed in the middle and lower section of the middle coal seam of the block,accounting for an average of 15%.The dull coal is sporadically developed at the bottom of the coal seam in the southwest corner of the block,with a thin thickness,accounting for 3%of the whole seam.Overall,the model can be used to quantitatively evaluate the distribution law of lithotype and provide strong support for CBM development.