韩城矿区H3井组煤体结构测井反演及三维地质建模

Logging inversion and three-dimensional geological modeling of coal structure in Hancheng H3 well group

为定量判识煤体结构,研究韩城H3井组煤体结构分布特征,在分析钻井取心资料的基础上,结合不同煤体结构煤层测井响应特征的差异,建立了煤体结构指数N和深侧向电阻率与微球聚焦电阻率比值R(LLD/MSFL)双参数判识煤体结构的方法。依据该反演模型完成29口井的煤体结构测井解释,厘清煤体结构纵向分布特征。进一步借助Petrel2015地质建模软件,采用随机建模方法实现了煤体结构空间分布特征的三维可视化。结果表明:在5号煤层中,N<40且R<81为Ⅰ类煤(原生-碎裂煤),N<42且8282

This paper is devoted to quantitatively identify coal structure and study the distribution characteristics of coal structure in Hancheng H3 well group.The drilling coring data and the differences of logging response characteristics of coal seams with different coal structure are analyzed.The method of identifying coal structure with dual parameters of coal structure index(N)and ratio of deep lateral resistivity to micro resistivity R(LLD/MSFL)is established.According to the inversion model,and the logging interpretation of coal structure in 29 wells was completed,and the vertical distribution characteristics of coal structure were clarified.Furthermore,the stochastic modeling method is used to realize the three-dimensional visualization of the spatial distribution characteristics of coal structure using the Petrel2015 three-dimensional geological modeling software.The results show that in No.5 coal seam,N<40 and R<81 are ClassⅠcoal(primary-cataclastic coal),N<42 and 8282<7?<108 are Class U coal(cataclastic-fragmented coal),and 65v/V<95 and R<95 are Class ID coal(fragmented-mylonitic coal).In No.l 1 coal seam,Nv42 and/?<70 are Class I coal(primary-cataclastic coal),28<A^<47 and 72<R<110 are Class H coal(cataclastic-fragmented coal),and 55<Nv89 and 49<7?<99 are Class HI coal(fragmented-mylonitic coal).The coal structure of No.5 coal seam in Hancheng H3 well group is mainly composed of Class ID coal and Class I coal,accounting for 43%and 37%,respectively.Class DI coal mainly distributes in the northeastern side of the study area and Class I coal distributes in the west and southeast of the study area.Class U coal only accounts for 9.2%,and there is also a small amount of parting(10.9%),and the thickness is thin.The coal structure of No.11 coal seam is mainly Class I coal,accounting for 62%and the thickness is thicker.Class U coal and Class DI coal are less,accounting for 20.6%and 12.1%respectively.Class D coal is mainly distributed in the eastern part of the study area and Class DI coal is mainly distributed in the central part of the study area.The thickness of Class U coal and Class IH coal is thinner and the parting is relatively less(5.5%).In general,the No.5 coal seam of Hancheng H3 well group is more affected by structure than No.1 1 coal seam.The coal is severely broken,and the structure coal is developed,which is unfavorable for coalbed methane exploitation.