【作者】 杨立成；

【导师】 李仲东；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2011， 硕士

【摘要】 针对大牛地气田构造简单、储层致密,常压—异常低压、含气层位多等特点,利用地质、测井、录井、测试等资料,在成藏基本条件的基础上重点对天然气输导体系、运移动力、成藏示踪、以及成藏期次等进行综合研究,进而建立成藏动力学模式,并进一步探讨影响天然气聚集的控制因素。研究发现,大牛地气田上古生界具有良好的烃源岩和储层条件,盖层质量好。通过研究砂体展布特征并结合前人研究的裂缝分布特征,认为研究区天然气聚集主要依靠砂体及砂体-裂缝型输导。研究泥岩压实特征并通过压力计算,认为研究区天然气运移主要动力为源储剩余压力差,浮力的作用较小。通过天然气烷烃气组分以及碳、氢同位素特征分析研究认为,该区主要为煤层气通过垂向运移形成富集,西南区烃源岩演化程度要高于东北区源岩演化程度。利用包裹体均一温度测试分析结合单井热演化史,认为大牛地上古生界气藏成藏主要分为两期:90～120℃和120～150℃,对应地质时间分别为早侏罗世—中侏罗世和中侏罗世—早白垩世末。其中早白垩世末为天然气成藏关键时期。根据烃源岩、产层及盖层分布等因素,将大牛地上古生界气藏分为两个成藏组合:源内成藏组合及近源成藏组合。源内成藏组合对应于太原组及山西组气藏,为自生自储式成藏,近源成藏组合对应于下石盒子气藏,为下生上储式成藏。综合研究区生储盖条件、输导体系、运移动力、成藏示踪、成藏期次等资料建立成藏模式,并分析认为大牛地上古生界天然气成藏主要为压力封存箱内煤系源岩生成的天然气在源储压差动力条件下经短距离垂向运移择优富集的结果。影响研究区天然气富集的主要因素为生气强度、储层质量、压力封存箱的内幕结构、输导体系以及成藏动力。更多还原

【Abstract】 With the feature of simple structure, tight reservoir, abnormal low pressure, several gas bearing intervals in the upper Paleozoic in Daniudi gasfield, using the comprehensive material of geology, well logging, drillinglog, testing, the transporting system, migration agent, tracer of migration and accumulation are focused on studying. And then establish the model of gas accumulation, and discuss the factors of gas accumulation.Study the condition of source rock, reservoir, cap, and research the types of transporting system through studying the distribution of sandstone combining with the distribution of fracture which was previous study. The result shows the gas migration and accumulation mainly through sand and sand-fracture transporting system. Through researching the compaction feature of mudstone, the pressure was calculated. It is discovered though the research that the difference of the pressure between resource rock and reservoir was the main migration agent. The results of gas component and carbon and hydrogen isotope show that coal gas migrated vertically and formed the gas accumulation. The maturity of resource rock in southwest is stronger than the one in northeast. Using the homogenization temperature of inclusions. combining with the thermal evolution history, the accumulation time could be divided two parts:90~120℃and 120～150℃, corresponding to Late Triassic -Middle Jurassic and middle Jurassic- late early Cretaceous respectively. And the late early Cretaceous was the key accumulation time. According to the factor of resource rock, production layer and cap, there are two accumulation combinations: inside source type and near source type. Inside source type corresponds to Taiyuan and Shanxi group while source type corresponding to Xiashihezi group.Basing on analyzing the resource rock, reservoir, caprock, transporting system, migration agent and tracer of migration and accumulation,it is pointed that the gas accumulation of Deniudi gas field in the upper Paleozoic was the result of coal gas accumulation through vertically migration under the differencepressure between resource and reservoir layers in the pressure compartment. The main factors of affecting gas accumulation are the gas generation intensity, the quality of reservoir,the internal composition of pressure compartment, transpoting system and migration agent.更多还原