深水少井区中深层岩性地层圈闭评价方法——以珠江口盆地白云凹陷恩平组白云11目标评价为例

白云凹陷是珠江口盆地已证实的富生烃凹陷，主力生烃层系恩平组的勘探前景亟待深入研究。受持续的构造沉降影响，白云凹陷恩平组构造圈闭匮乏，但构造、沉积条件均有利于岩性地层圈闭发育与油气藏的形成。在详细分析恩平组地质条件基础上，搜索落实潜在的岩性地层目标21个，并优选白云11目标进行精细评价。结果表明，白云11目标为三级层序低位期的低位扇沉积，砂体发育，圈闭落实，储层物性良好，成藏条件优越，含气异常特征明显，为白云凹陷中深层有利的自生自储型勘探目标。恩平组自生自储型岩性地层油气藏是白云凹陷油气勘探新领域，而中深层少井条件下的岩性地层圈闭评价方法则为深水区该类油气藏的勘探评价提供了技术支持。

The evaluation methods of mid-deep litho-stratigraphic traps in deep-water and less-well blocks:a case study of Target Baiyun 11 in Enping Formation,Baiyun sag,Pearl River Mouth Basin

Baiyun sag is confirmed to be a hydrocarbon-rich sag in Pearl River Mouth Basin, where the exploration potential of chief source rocks in Enping Formation is urgent to be studied. Because of continuous subsidence, structural traps are insufficient in Enping Formation, Baiyun sag, but structural and depositional conditions are favorable to the development of litho-stratigraphic traps and hydrocarbon accumulation. Based on detailed geological conditions analysis, a total of 21 potential litho-stratigraphic targets were searched and confirmed, and Target Baiyun 11 was selected preferably for fine evaluation. Evaluation results show that Target Baiyun 11 is low-stand fan that deposited during lowstand systems tract in the third-order sequence, characterized by the development of sand bodies, traps confirmation, favorable reservoir physical properties, superior reservoir forming conditions and distinct gas-bearing anomaly, thus becoming the favorable self-generation and self-reserving exploration target of mid-deep reservoirs in Baiyun sag. The self-generation and self-reserving litho-stratigraphic reservoirs in Enping Formation are the new field for hydrocarbon exploration in the sag. Meanwhile, the evaluation method of lithologic trap in the deep-water and less-well conditions provides a technical support for the exploration and evaluation of such reservoirs in deep waters.