流体封存箱与天然气成藏——以鄂尔多斯盆地苏里格气田为例

Fluid Compartment and Gas Accumulation – Take Sulige Gas Field in Ordos Basin for Example

引入流体封存箱理论,探讨了异常压力与流体封存箱形成的关系,并建立了流体封存箱模型。通过气源岩埋藏史、构造热演化史、次生孔隙发育史、成岩圈闭孕育史及天然气运聚史等五史分析研究,并结合气液包裹体均一温度及自生伊利石K—Ar同位素测年资料,将鄂尔多斯盆地苏里格气田盒8、山1气藏的形成时间确定为晚侏罗世—早白垩世。并在此基础上,总结了研究区天然气成藏演化模式。通过对研究区生、储、盖、圈、运、保等天然气成藏要素的综合研究,总结了天然气富集规律:生烃强度控制了天然气的富集程度;优势运移通道是天然气运聚的基本途径;储层物性优劣是影响天然气富集的关键因素。

With introduction of the fluid compartment theory, this paper discusses the relations between abnormal pressure and fluid compartment and establishes the fluid compartment model. Based on analysis of source rock buried history, structural thermal development history, secondary porous and fractural development history, diagenetic trap history and natural gas migration and accumulation history and combined with the homogenization temperature of gas-liquid inclusions and authigenicillite K and Ar isotopic dating data, the time for development of He-8 and Shah-1 gas reservoirs of Sulige Gas Field in Ordos Basin is determined as Late Jurassic - Early Cretaceous. The paper also summarizes the natural gas accumulation and development pattern in the study region on the basis of the above-mentioned conclusion. It makes a comprehensive study of the natural gas accumulation elements in the study region, such as sourcing, reservoir, capping, sealing, migration and storage. The summarized natural gas abundance law indicates that sourcing intensity controls natural gas abundance degree while the favorable migration channels are the basic paths for natural gas migration. The physical properties of reservoir are the key factors to influence natural gas abundance.