珠三坳陷琼海凸起油气运聚研究

A study on the migration and accumulation of oil and gas in Qionghai uplift, Zhusan depression

琼海凸起发现多个油田和含油构造，但本身不具备生烃能力，因此研究油气来源问题对下一步勘探部署十分重要。成藏流体在油区范围内呈非均质性分布，这种特征实际上是油气运聚、成藏复杂性的真实记录。从该角度出发，详细解剖文昌１３－２油田原油成熟度、含氮化合物及原油物性等非均质性分布特点，并以此为基础，细划出各油田的充注方向和充注期次，同时结合区域地质资料，探讨了珠三坳陷琼海凸起油气运聚特征。研究认为，该区目前发现的油气主要来源于文昌Ｂ凹陷文昌组滨浅湖相烃源岩，且存在珠江期和粤海─第四纪两次大的运移期。琼海凸起与文昌Ｂ凹陷过渡部位的北部斜坡带是油气运移的必经之道，具备油气富集、非构造圈闭发育的条件，是今后勘探部署的有利场所。

A lot of oil and gas traps and petroliferous structures have been discovered in Qionghai uplift. However all of them have no ability of oil and gas generation; and therefore it is very important to study origin of oil and gas for further exploration. Pool forming fluids exhibit heterogeneous distribution characteristics in this oil region. This characteristic is really an actual record of complexity in oil and gas migration and accumulation as Well as pool forming. Starting from this viewpoint, heterogeneous distribution characteristics of maturation of crude oil, nitrogenous compounds, and properties of crude oil from Wenchang 13-2 oil field are analyzed in detail. On the basis of analytical results, the filling direction and filling stages are classified in great detail. Combined with regional geological information , the characteristics of oil and gas migration and accumulation in Qionghai uplift, Zhusan depression are thoroughly studied. The study recognizes that the oil and gas discovered so far are mainly originated from shallow lake shore source rocks in Wenchang Formation in Wenchang B sag, and 2 migration stages──Zhujiang era and Yuehai era-Quaternary stages are observed. The north slope between Qionghai uplift and transitional zone of Wenchang B sag is the necessary pathway for oil and gas migration, Where existed conditions for oil and gas enrichment and development of non-structural traps; and which are the favorable places for further exploration.