珠江口盆地顺德北凹陷新生代断裂特征与演化分析  

Analysis of Cenozoic faults characteristics and evolution in North Shunde sag,the Pearl River Mouth Basin

作　　者：龚宇 呙诗阳 周晨 窦婧瑛 GONG Yu;GUO Shiyang;ZHOU Chen;DOU Jingying(Research Institute of Hainan Branch of CNOOC China Limited,Haikou,Hainan 570100,China)

机构地区：[1]中海石油(中国)有限公司海南分公司研究院,海南海口570100

出　　处：《世界石油工业》2025年第2期45-57,共13页World Petroleum Industry

基　　金：中国海洋石油集团有限公司“十四五”重大科技项目“南海北部深水区勘探关键技术”(KJGG2021-0100)。

摘　　要：为了深入探究顺德北凹陷的断裂特征、凹陷形成与演化过程,解决因以往研究不足而导致的油气成藏机理不清等问题,依托新采集的1500 km^(2)高精度三维地震资料和2口新钻井资料,在对顺德北凹陷地层识别和断裂解释的基础上,运用断裂走向、活动性分析、平衡剖面恢复等技术,系统开展断裂特征分析、构造样式识别、演化分析和成凹机制研究。研究结果表明,顺德北凹陷发育始新世、渐新世、中新世3期断裂,依据断裂的控制作用可进一步划分为Ⅰ级控凹断裂、Ⅱ级控洼断裂、Ⅲ级控带断裂、Ⅳ级控圈断裂及Ⅴ级伴生断裂。在走滑、斜向伸展双重应力作用下,形成了弱走滑—强斜向伸展、强走滑—弱斜向伸展、弱走滑—弱斜向伸展这3类不同的叠加构造样式。凹陷在不同时期呈现出不同成凹模式,断陷期为强斜向伸展—弱走滑成凹模式,断—拗转换期为强斜向伸展—强走滑成凹模式,拗陷期为弱斜向伸展—弱走滑成凹模式。并且三期差异成凹过程分别控制了凹陷内烃源岩、储层、盖层的分布。结论认为,该项研究成果对顺德北凹陷油气成藏机理研究具有推进作用,同时也可为类似边缘凹陷的构造分析提供借鉴,助力相关区域的油气勘探工作。In order to deeply explore the fault characteristics,formation and evolution process of Shunde North Sag,solve the problem of restricting the research on hydrocarbon accumulation mechanism due to insufficient previous research,and improve the exploration level of this area.The method adopted is to rely on the newly acquired 1500 km^(2) high-precision 3D seismic data and two new drilling data.Based on the stratigraphic identification and fault interpretation of Shunde North Sag,technologies such as fault strike,activity analysis,and balanced cross-section restoration are used to systematically carry out fault characteristic analysis,structural style identification,evolution analysis and sag-forming mechanism research.The research results show that there are three periods of faults in Shunde North Sag,namely Eocene,Oligocene and Miocene.According to the controlling effects of faults,they can be further divided into GradeⅠsag-controlling faults,GradeⅡsub-sag-controlling faults,GradeⅢzone-controlling faults,GradeⅣtrap-controlling faults and GradeⅤassociated faults.Under the dual stress of strike-slip and oblique extension,three different superimposed structural styles have been formed,namely weak strike-slip-strong oblique extension,strong strike-slip-weak oblique extension,and weak strike-slip-weak oblique extension.The sag has different sag-forming models in different periods.The rifting period is a strong oblique extension-weak strike-slip sag-forming model,the rifting-depression transition period is a strong oblique extension-strong strike-slip sag-forming model,and the depression period is a weak oblique extension-weak strike-slip sag-forming model.And the three-period differential sag-forming processes respectively control the distribution of hydrocarbon sources,reservoirs and caps in the sag.It is concluded that the research results play an important role in promoting the research on hydrocarbon accumulation mechanism in Shunde North Sag.At the same time,it can also provide effective reference for th

关 键 词：珠江口盆地 顺德北凹陷 新生代 断裂特征 构造演化 成凹机制 

分 类 号：TE12[石油与天然气工程—油气勘探] P631.4[天文地球—地质矿产勘探]