泌阳凹陷古城油田油气成藏过程分析及勘探方向

在对泌阳凹陷古城油田油气成藏条件及其空间配置关系进行分析的基础上,利用流体包裹体技术确定油气成藏期,结合生烃史模拟、油源精细对比和构造演化史分析结果,分析油气运移充注方式,剖析油气成藏过程。结果表明:古近系核一上亚段至核三下亚段生成的大量低成熟油气缓慢向古城鼻状构造充注,形成一定规模的古油藏(第一期充注成藏);早喜马拉雅期(古近纪廖庄期末构造抬升期)构造运动造成区域性地层抬升剥蚀和大量断层活动,导致早期古油藏的破坏和核三上亚段生成的成熟油气大规模快速充注,驱替核三下亚段生成的油气,形成了大量断块、断鼻油气藏,奠定了现今古城油田油气分布格局(第二期充注成藏);晚喜马拉雅期(新近纪凤凰镇末期)构造运动导致第一、第二期形成油气藏的调整和少量高成熟油气的再次充注,形成了现今的古城油田(第三期充注成藏)。

Discussion on Pool-forming and Its Exploration Potential in Gucheng Oilfield ,Biyang Sag

Based on analysis of the conditions of pool-forming and their space-matching relationship of Gucheng oilfield in Biyang Sag, thepool-forming stages are determined by using fluid inclusion technique, combined with the results of hydrocarbon generation simulation,fine oil-source correlation and tectonic evolution history, the styles of oil migration & charging and the processes of pool-charging arediscussed in detail. The above results indicate that there exist three stages of oil charging: (1) In the first stage of oil charging, the large amountof low-mature oil-gas generated from the upper part of first member of Eogene Hetaoyuan Formation, slowly poured toward to Gucheng nosetectonic, and formed a certain oil-gas reservoirs;(2) In the second stage during Early Himalayan, the tectonic activity resulted in uplifting anderosion of regional strata and faults activity, meanwhile destroyed the paleo-reservoirs and oil full-charged largely and rapidly ,which generatedfrom the upper part of third member of Hetaoyuan Formation, so drove and replaced oil/gas generated from the lower part of third member ofHetaoyuan Formation, finally formed lots of fault-block and fault-nose reservoirs, laid a foundation for the distribution framework of presentGucheng oilfield;(3) In the third stage during Later Himalayan, new tectonic movements resulted in the adjustment of oil/gas reservoirs formedin the first and second pool-forming stages, and made a few high-mature oil/gas recharge and formed present Gucheng oilfield.