老厂矿区煤体结构测井判识与分布规律

煤体结构是制约煤储层可改造性的最重要地质因素之一。基于视电阻率、人工伽玛和自然伽玛射线测井响应,通过钻孔及煤层对比分析,建立了滇东老厂矿区晚二叠世龙潭组煤体结构的判识方法,并对9、13、19号三套主煤层的煤体结构及其分布特征进行了研究。结果表明,在利用测井响应曲线判识煤体结构时,采用对比的方法可以减少相应误差,从而更准确判识出结果。煤体结构变化与构造发育程度相关。平面上,一勘区构造较为简单,原生结构煤(Ⅰ类)较发育;白龙山井田受次级褶曲及断层发育的影响,构造煤(Ⅲ类)最发育;雨旺井田构造相对简单,主要发育过渡型(2类)煤。垂向上,随着煤层埋深增加,Ⅰ+Ⅱ类煤的厚度比例有增高趋势,且皆超过60%,揭示出深部煤层受构造破坏的影响程度较浅部低。

Logging discrimination of coal structures and their distribution in the Laochang mining area, eastern Yunnan Province

The coal body structure is one of the most important geological factors that restrict the reformability of coal reservoirs. Based on apparent resistivity, artificial gamma, and natural gamma-ray logging responses, a method for identifying the coal structures of the Longtan Formation of the Late Permian Laochang mining area in eastern Yunnan was established through borehole and coal seam analysis. And the coal structures and their distribution characteristics of the three main seams of No.9, No.13 and No.19 were studied. The results show that when using the logging response curve to identify the coal structure, the comparison method can reduce the corresponding error, and thus more accurately discriminate the results. The structural change of the coal body is related to the degree of structural development. On a plane, the structure of a survey area is relatively simple, and the primary structural coal (Type I) is relatively well developed. The Bailongshan minefield has been affected by the secondary folds and faults, where structural coal (Type III) is the most developed. The structure of the Yushang minefield is also relatively simple with transition (Type II) coal. Vertically, with increasing depth of the coal seam, the proportion of thickness of the type I+II coal tends to increase, all exceeding 60%, revealing that the coal seam at depth was less affected by structural damage than that in the shallow subsurface.