摘要
根据鄂尔多斯盆地北部沉积埋藏史、成烃史、地热史和烃类包裹体分析、地层剥蚀厚度、沉积速度等资料,结合鄂尔多斯盆地上古生界普遍低压异常、储层致密、构造简单、含气层分散、天然气聚集受封存箱控制的特点,对盆地北部上古生界异常压力分布规律、压力成因及演化历史的研究认为,该区上古生界具备压力封存箱发育的地质环境。压力封存箱区域分布的特点是上古生界为一个高低压相间共存的复杂压力封存箱型含气系统,储层属异常低压-常压,泥岩仍保持幅度不等的高压。压力封存箱的形状、内幕结构、箱内砂泥岩的配置关系控制了箱内天然气藏的分布。
Abstract
Based on previous research data of sedimentary burial history,hydrocarbon-generating history,geothermal history,inclusion analysis,denuded thickness,deposition velocity,and etc.,in the northern Ordos basin,a study is initiated with the aim of understanding the pattern of abnormal pressure distribution,and the genesis and evolution of pressure in the Upper Paleozoic of the basin by combining its characteristics of universal low abnormal pressure,tight reservoirs,simple sturctures,dispersed gas pays,and compartment-controlled gas accumulation.The results confirm the existence of favorable geological conditions for developing compartments in the Upper Paleozoic of the basin.The Upper Paleozoic is recognized to be a complicate gas system with high and low pressure coexisted in compartments,i.e.the reservoir belongs to normal pressure-abnormal low pressure,while the mudstone still maintains high pressure.The study also suggests that the shape,inner structure,and sandstone-mudstone relationship of the compartment decide the distribution of gas reservoirs in the compartment.
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