珠一坳陷北部洼陷带古近系潜在富生烃洼陷评价

摘要

珠江口盆地珠一坳陷北部洼陷带古近系可划分为8个洼陷，地震相类比分析认为有5个洼陷的文昌组发育中深湖相沉积，其中西江主洼、惠州5洼及惠州10洼的文昌组中深湖相分布规模较大；北部洼陷带恩平组沉积时期为局限性沼泽化浅水沉积，湖沼相煤系泥岩和浅湖相泥岩是恩平组主要烃源岩，其中惠州8洼恩平组湖沼相分布规模最大，而西江主洼则发育较大规模的浅湖相沉积。对比北部洼陷带文昌组与恩平组2套烃源岩的分布规模、热成熟程度及盆地生烃模拟等指标，综合分析认为西江主洼、惠州5洼、惠州10洼和惠州8洼为潜在富生烃洼陷，具有较好的勘探潜力。%In the northern sag belt,Zhu 1 depres-sion,Pearl River Mouth basin,there are eight Pa-leogene sags,five of which are believed to containWenchang formation sediments of semideep lacus-trine facies according to the analogy of seismic faci-es,with their larger distribution in Xijiang First,Huizhou 5 and Huizhou 10 sags.During Enpingformation sedimentation,the northern sag belt wasin a confined,palustral and shallow water environ-ment,and the main source rocks in Enping forma-tion are the coal-measure mudstone of lacustrine-palustral facies and the shale of shallow lacustrinefacies,with the largest distribution of the lacus-trine-palustral facies in Huizhou 8 sag and the lar-ger distribution of the shallow lacustrine facies inXijiang First sag.By comprehensively analyzingthe distribution,thermal maturity and basin hy-drocarbon-generation simulation indicators of thetwo sets of source rock in Wenchang and Enpingformation,it is considered that Xijiang First,Huizhou 5 Huizhou 10 and Huizhou 8 sags are la-tent hydrocarbon-rich sags with great explorationpotential.