彬长矿区延安组煤层发育特征及其控制因素分析

摘要

煤层是煤层气赋存的载体,分析煤层发育特征及其控制因素,有助于煤层开采与煤层气开发的研究.依据基础地质资料,利用基准面旋回与沉积相、岩性组合、测井曲线组合,以及煤层自身特征等方法,研究了彬长矿区延安组煤层发育特征,划分并对比了含煤地层.在此基础上,综合分析了煤层发育特征的控制因素.结果表明,延安组地层自下而上可划分为三段,其中,4#主采煤层位于延一段,主要发育在四级层序上升半旋回顶部的沼泽相中.4#煤层顶底板以碳质泥岩等细粒沉积为主,煤层的测井曲线组合特征为"三高一低一负",具有单层厚度大、横向有规律变化的特点.研究区经历了多期构造运动,而晚喜马拉雅运动对侏罗系煤层赋存状态影响最大.煤层多发育在地势低洼的泥炭沼泽环境中,气候湿润,属于亚热带～暖温带,有利于成煤作用的形成.%Coal is the carrier of coalbed methane, hence the analysis of the development characteristics of coal seam and the controlling factors contributes to the research on coal mining and coalbed methane development. According to the basic geological data, and by using the methods of the base level cycle, sedimentary facies, lithological, combination of logging curves and the feature of coal itself, the coal development features of Yanan forma tion in Binchang area are learned, the coal-bearing strata is correlated and the controlling factors are analyzed. The results show that Yanan formation can be divided into three parts from the bottom to the top, and 4 coal seam locates in Yan 1 member, which mainly deposits in swamp facies at the top of the upper half cycle of fourth order sequence. The top and bottom of 4 coal seam are carbon mudstone and other fine sediment, and the logging curves combination of the coal seam featured "three high, one low and one negative". The 4 coal seam has the feature of big monolayer thickness and regular changes horizontally. Several tectonic movements has occurred in the study area, and the late Himalayan movement has the greatest impact on the occurrence of Jurassic coal seam. Coal seam mainly deposits in the lowlying peat swamp facies, which belongs to the subtropical-warm temperate zone with wet weather, and is favorable to the coal formation.