鄂尔多斯盆地东缘上古生界煤系叠置含气系统发育的沉积控制机理

发布时间：2018-05-08 00:25

本文选题：鄂尔多斯盆地东缘 + 晚古生代　；参考：《天然气工业》2017年11期

【摘要】：鄂尔多斯盆地东缘煤层气、致密砂岩气及页岩气"三气"共存,该区上古生界煤系储层垂向上存在着多个独立的含气系统,目前对该类煤系叠置含气系统发育的沉积控制机理尚缺乏系统深入的研究。为此,基于该区临兴区块上石炭统本溪组—下二叠统山西组钻井岩心观察及钻井、测井资料分析结果,探讨了上述问题。研究结果表明:(1)该区煤系叠置含气系统的发育受控于层序格架内具低孔隙度、低渗透率和高突破压力的含菱铁矿层(关键层)的空间展布;(2)关键层的发育受控于区域海侵事件层的空间分布,主要发育于最大海泛面附近并构成叠置含气系统隔水阻气的边界;(3)二级层序内最大海泛面附近广泛发育的关键层,构成了全区稳定发育的含气系统边界,三级层序最大海泛面附近发育的关键层常因后期(水下)分流河道冲刷切割而保存不全,促使相邻层序的煤系储层组合成统一的含气系统,为该区煤层气与致密砂岩气的共采创造了有利的地质条件。
[Abstract]:Coalbed methane, tight sandstone gas and shale gas coexist in the eastern margin of Ordos Basin. There are several independent gas-bearing systems in the upper Paleozoic coal series reservoir vertical direction. At present, the depositional control mechanism of the superimposed gas bearing system of this kind of coal measures is still lack of systematic and deep research. Therefore, based on the core observation and drilling data analysis of the upper Carboniferous Benxi formation and lower Permian Shanxi formation in Linxing block, the above problems are discussed. The results show that the development of superimposed gas-bearing system of coal measures in this area is controlled by the low porosity in the sequence framework. The development of the key layers with low permeability and high breakthrough pressure is controlled by the spatial distribution of regional transgressive event layers. The key layers, which are mainly developed near the largest sea flooding surface and constitute the boundary of the superimposed gas-bearing system to prevent water and gas, are widely developed near the largest sea panoramic surface in the second order sequence, and constitute the boundary of the gas-bearing system which develops stably in the whole area. The key layers developed near the largest sea flooding surface of the third order sequence are often not preserved completely due to the scour and cutting of the distributary channel in the late stage (underwater), which urges the coalbed reservoirs of the adjacent sequences to be combined into a unified gas-bearing system. It creates favorable geological conditions for coproduction of coalbed methane and tight sandstone gas in this area.
【作者单位】：煤层气资源与成藏过程教育部重点实验室;中国矿业大学资源与地球科学学院;中联煤层气有限责任公司;
【基金】：国家科技重大专项(编号:2016ZX05044-002-001、2016ZX05066-001-004) 国家自然科学基金项目(编号:41672146、41541046)
【分类号】：P618.13

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