摘要
在前陆冲断带天然气成藏的诸多控制因素中,断裂的发育决定着圈闭的形成、油气的运移聚集以及盖层的封闭性,以断层发育为核心的断源储盖的空间组合样式决定了油气的输导能力、圈闭的封闭性和充满度,从而最终控制了天然气的成藏。根据库车坳陷前陆冲断带不同地区的构造特点、生储盖组合关系以及成藏主控因素的不同,解剖已知油气藏的成藏特征,构建了库车坳陷前陆冲断带断源储盖组合样式,并阐述了4种不同断源储盖组合对天然气成藏的控制作用。其中,克深型断源储盖组合为最佳,向下既沟通侏罗系气源,向上又未断开库姆格列姆膏盐岩盖层,既是天然气运聚的良好通道,又未破坏盖层的封闭性,从而造成天然气的连片分布。克拉苏型由于断层不仅断开了巴什基奇克储层,而且还断开了膏盐岩盖层,因此圈闭的侧向封堵性是其成藏的关键。大宛齐型是盐上成藏,穿盐断层的输导以及盐上圈闭的有效性是其成藏的关键。依其克里克型则是自生自储,其成藏的关键是上倾控圈断层是否封闭以及断层两盘的岩性对接关系。
Fault development plays a vital role in all the factors controlling gas accumulation in foreland thrust belt, which determines the migration and accumulation of oil and gas, the formation of trap, and the sealing capacity of caprocks. Therefore, the combinations of fault- source-reservoir-cap, of which fault development is the core, determine the channel capacity of oil and gas, the sealing features and the fullness degree of traps, and ultimately control the accumulation of gas. According to the structure characteristics, the association of source- reservoir-cap, the main controlling factors of accumulation and the analysis of the known hydrocarbon reservoirs in different regions of the foreland thrust belt in Kuqa Depression, the combinations of fault-source-reservoir-cap were founded and the control of different combinations on gas accumulation was elaborated in this paper. The combination of fault-source-reservoir-cap in Keshen is the most optimal, which is connected with Jurassic gas at the bottom and does not cut through Kumugelemu's gypsum-salt cap on the top. Not only does it act as a good channel of gas accumulation and migration, but also the closure of caprock is not destroyed, resulting in the continuous distribution of gas. In Kelasu region the fault cuts through both Bashenjiqike's reservoir and gypsum-salt cap. For these reasons, whether the closure of the cap can accumulate gas is the lateral sealing trap. Gas is accumulated above gypsum-salt rocks in Dawanqi, thus the main factors for gas accumulation are channel capacity of faults that cut through gypsum-salt rocks and suprasalt trap effectiveness. Ichicklick's source and reservoir are in the same region, so the key factors of gas accumulation are the sealing ability of the updip faults which control the trap and the lithology joint relationship of each wall.
出处
《中国石油勘探》
CAS
2013年第5期10-14,共5页
China Petroleum Exploration
基金
国家自然科学基金项目"西藏措勤盆地白垩纪中期构造事件及其油气地质意义"(41172129)
关键词
前陆冲断带
断源储盖组合样式
控藏作用
库车坳陷
塔里木盆地
foreland thrust belt, fault-source-reservoir-cap combinations, control, Kuqa Depression, Tarim Basin