In recent years, several large gas fields have been discovered in western Qiongdongnan Basin. It is important and necessary to illustrate their sedimentary characteristics and hydrocarbon migration so that more gas fields could be discovered in the future. Previous regional tectonic-sedimentary researchers show that large-scale source rock of the Yacheng Formation developed in the Ledong and Lingshui sags due to the Red River Fault pull-apart strike slip in early Oligocene. The main targets for hydrocarbon exploration in this area are the Miocene deep water reservoirs. In late Miocene, the Huangliu Formation reservoirs are composed of the early channels which were sourced by river systems in Hainan uplift and the consequent channels were sourced by Qiupen River in Kunsong uplift. Both axial channels exhibit unique spatial distribution patterns and geometries. The other kind of reservoir developed in the middle Miocene Meishan Formation, which compose of slope break-controlled submarine fan. They can be further classified into three types—slope channelized fan, basin floor fan, and bottom current reworked fan. The various fans have different reservoir quality. These two kinds of reservoirs contribute to four types of litho-stratigraphic traps under the actions of sedimentation and subsidence. The overpressure caused by hydrocarbon generation can fracture deeper strata and result in regional fractured network for hydrocarbon migration. Therefore, free gas driven by overpressure and buoyancy force can be migrated into Miocene litho-stratigraphic traps to accumulate. The revealed genesis of Miocene lithologic trap and hydrocarbon accumulation in the Qiongdongnan Basin would greatly contribute to the further hydrocarbon exploration in northern South China Sea and can be helpful for other deep water areas around the world.

中文翻译：

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南海北部琼东南盆地中新世岩性地层圈闭成因及油气成藏

近年来，在琼东南盆地西部发现了几个大型气田。说明它们的沉积特征和碳氢化合物运移是重要且必要的，以便将来可以发现更多的气田。先前的区域性构造沉积研究人员表明，由于渐新世早期的红河断裂拉动走滑带，乐东凹陷和陵水凹陷凹陷形成了崖城组的大型烃源岩。该地区油气勘探的主要目标是中新世深层水库。中新世晚期，黄柳组储层由海南隆起的早期河道组成，其结果是昆松隆起的秋蓬河。两个轴向通道均显示出独特的空间分布模式和几何形状。另一种是在中新世梅山组中发育的，由坡折控制的海底扇组成。它们可以进一步分为三种类型：斜通道风扇，台盆地板风扇和底流返修风扇。各种风扇具有不同的水库质量。在沉积和沉降作用下，这两种储层共同构成了四种类型的岩石地层圈闭。由碳氢化合物产生引起的超压可能会使较深的地层破裂，并导致烃类运移的区域性破裂网络。因此，由超压和浮力驱动的自由气可以迁移到中新世的地层圈闭中。