陆丰北地区构造特征及恩平组勘探方向

Tectonic characteristics of Lufeng North area and the exploration direction of the Enping Formation

在三维地震资料精细解释的基础上,系统分析了珠江口盆地陆丰北地区的断裂体系和洼陷结构,探讨了恩平组的油气勘探潜力和方向。研究结果表明,陆丰北地区断裂系统具有典型的上、下双层结构,发育伸展型和张扭型2种应力类型的断裂组合样式;文昌期发育地堑式的陆丰07洼,恩平期发育半地堑式的惠州05洼和惠州11洼,厚度和面积均较大。陆丰凹陷控洼断裂在古近纪具有“翘翘板”的特点,即从早文昌期到晚恩平期活动强度整体向北迁移;陆丰北地区恩平期物源主要来源于西北侧和东边,以长轴断槽式源 汇体系和沟谷源 汇体系为主要物源通道,其中在恩平早期广泛发育中深湖相沉积,是该区的主力烃源岩,而恩平晚期裂陷作用减弱,以浅水三角洲沉积为主,相比陆丰南勘探成熟区的恩平组具有更好的储盖组合条件;惠州05底辟构造带和洼陷区的陡坡带发育大量的断背斜、断鼻和断块,是陆丰北地区探索恩平组勘探潜力可以优先开展评价的区域。

Based on the fine interpretation of three-dimensional seismic data,the fault system and subsag structure of the Lufeng North area in the Pearl River Mouth Basin were systematically analyzed,and the oil and gas exploration potentials and direction of the Enping Formation were discussed.The research results show that the fault system in the Lufeng North area presents a typical upper and lower double-layered structure,and it developed two fault assemblage patterns with the extensional and transtensional stress types,respectively.The garben-type Lufeng 07 subsag was developed in the Wenchang stage,and the semi-garben Huizhou 05/Huizhou 11 subsags were developed in the Enping stage,all of them have obvious thickness and area.The subsag-control ling faults in the Lufeng subsag exhibited the characteristics of"seesaw"in the Paleogene,that is,the activity intensity migrated northward from the early Wenchang period to the late Enping stage as a whole;the provenances of the Enping stage in the Lufeng North area mainly came from the northwest and east sides,taking the long-axis trough-type source-sink system and the gully source-sink system as the major provenance channels.Among them,the deep lake facies sediments were widely developed in the early Enping stage,and they were the main source rocks in this area.The rifting was weakened in the late Enping stage,and it mainly developed the shallow-water delta sediments,which own the better reservoir-caprock assemblage conditions than the Enping Formation in the mature exploration area of Lufeng South.The Huizhou 05 diapir structural zone and the steep slope of subsag developed a large number of fault anticlines,fault noses and fault blocks where the exploration potentials of the Enping Formation can be preferentially evaluated in the Lufeng North area.