珠江口盆地陆丰南地区古近系全油气系统特征与油气藏有序分布

Characteristics of Paleogene Whole Petroleum System and Orderly Distribution of Oil and Gas Reservoirs in South Lufeng Depression,Pearl River Mouth Basin

珠江口盆地陆丰凹陷古近系发育多种类型的油气资源,尤其形成了具有多样特征的复合类和改造类油气藏,利用经典“含油气系统”理论难以解释油气藏成因机制和分布规律.基于全油气系统新概念阐述了它们的形成分布.结果表明,在古近系储层致密演化过程中,文昌组和恩平组两套烃源岩提供了早期排出烃、晚期排出烃、源内滞留烃三种原始烃量,源岩内部和周边砂岩储集层因成岩-压实差异发育了油气自由动力场、局限动力场和束缚动力场,全油气系统内三类原始烃量和3个动力场的耦合作用造成自下而上呈现出“页岩油气-致密油气-常规油气”的有序分布.这种规律性认识对于研究区不同类型油气资源分布预测和勘探具有重要的指导意义.

Many types of oil and gas resources have been developed in the Paleogene of Lufeng Depression,Pearl River Mouth Basin,especially the complex and reformed oil and gas reservoirs with various characteristics.It is difficult to explain the genetic mechanism and distribution law of oil and gas reservoirs by using the classical“petroleum system”theory.Based on the new concept of the whole petroleum system,in this paper it expounds their formation and distribution.It is found that during the tight evolution of Paleogene reservoirs,the two sets of source rocks of Wenchang Formation and Enping Formation provided three kinds of original hydrocarbon quantities:early discharged hydrocarbon,late discharged hydrocarbon and retained hydrocarbon in the source.Due to the diagenetic compaction difference,the sandstone reservoirs inside and around the source rock developed oil and gas free dynamic field,limited dynamic field and bound dynamic field,The coupling effect of three kinds of original hydrocarbon quantities and three dynamic fields in the whole oil and gas system forms an orderly distribution of“shale oil and gas,tight oil and gas and conventional oil and gas”from bottom to top.This understanding of regularity has important guiding significance for the distribution prediction and exploration of different types of oil and gas resources in the study area.