东濮凹陷盐岩成因与油气聚集

Discussion on Genesis of Halites and Petroleum Accumulation in Dongpu Depression

东濮凹陷是一个油气丰富的盐源盆地 ,油气富集与盐岩有着密切关系 ,许多学者对东濮凹陷北部盐岩的成因都进行过有益的探讨。沙三3 亚段岩心中出现的红色地层是盐岩形成于浅水的标志 ,将东濮凹陷的蒸发岩和海水蒸发成岩的序列相比较后认为 ,东濮凹陷的盐岩为海侵的浅水蒸发成盐 ,在湖盆的沉积过程中存在低水位体系域、湖盆收缩体系域和高水位体系域。湖平面的频繁变化形成了盐与泥岩、页岩的互层以及砂岩与泥岩、页岩的互层 ,前者是很好的盖层和生油岩 ,后者是良好的生、储、盖组合。浅水成盐的模式证明了砂体可与盐岩同期发育 。

Dongpu is a petroleum prolific salty depression.The oil in place proven shows that there is a close relationship between petroleum accumulation and halites.Many scholars have studied the forming factors of the halites in the northern part of the depression.The theory of halites formed in deep-water has been dominating.Based on the cores observed,on the facts of appearance of red layers(shallow water remarks)and on the compression between the evaporating rocks in this depression and the evaporating rocks from sea water,this paper reveals that the halites were formed from marine invasion shallow water.There were three system tracts in the depositional process of the depression,namely the low level,the receding and the high level.The halites and the main sand bodies were deposited during the period of low level;the dark clay sandstones and shale were deposited during the period of high level.Frequent changes of the lacustrine level formed the multiple source-reservoir-cap assemblages.