琼东南盆地崖北凹陷构造沉积特征及油气勘探潜力  

Structural-sedimentary characteristics and oil and gas exploration potential of Yabei sag of the Qiongdongnan Basin

作　　者：宋瑞有 马光克 何小胡 万阳 贺礼文 SONG Ruiyou;MA Guangke;HE Xiaohu;WAN Yang;HE Liwen(CNOOC China Limited,Hainan Branch,Haikou 570312,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南海口570312

出　　处：《热带海洋学报》2024年第5期93-105,共13页Journal of Tropical Oceanography

基　　金：国家科技重大专项(KJGG2022-0404)。

摘　　要：崖北凹陷是南海琼东南盆地西北缘的边缘凹陷,勘探历程久,但受地震资料等因素制约而勘探程度低,钻井无商业发现,烃源条件落实程度低。为落实崖北凹陷油气地质条件,推动该凹陷的勘探进程,用新采集的高品质三维地震资料,结合已钻井资料,类比分析相邻盆地烃源岩地震相,厘清了崖北凹陷的断裂、构造、沉积特征和烃源岩分布,并依据区域地质应力背景分析了其成因机制,讨论了崖北凹陷油气成藏条件及勘探部署方向。结果认为崖北凹陷受5号断裂控制凹陷整体呈北断南超的构造沉积特征,纵向上“下断上拗”,新近系地层区域南倾、少有盆内断层发育,古近系断裂控凹,始新统中深湖相烃源岩主要发育在崖城9洼,崖城组煤系烃源岩发育在凹陷东南部位。最终认为,崖北凹陷烃源具有“西油东气”的特征,凹陷西部及西南斜坡和近崖城9洼的陡坡古近系圈闭是找油方向,而凹陷东南部位的凹中隆及围区圈闭天然气勘探前景好。The Yabei sag is a marginal sag in the northwest margin of the Qiongdongnan Basin in the South China Sea.The Yabei sag has a long exploration history,but restricted by factors such as seismic data,the exploration degree is low,there is no commercial discovery in drillings,and the implementation degree of hydrocarbon source conditions is low.In order to implement the oil and gas geological conditions of Yabei sag and promote the exploration process,using the newly acquired high-quality threedimensional seismic data,combined with the drilled wells,analogically analyzed the seismic facies of source rocks in adjacent basins,clarified the fault,structure,sedimentary characteristics and source rock distribution in the Yabei sag,and analyzed its genetic mechanism according to the regional geological stress background.The hydrocarbon accumulation conditions and exploration deployment direction in the Yabei sag were discussed.The results show that Yabei sag is controlled by No.5 fault.The sag is characterized by structural sedimentation of the North Fault and South overtopping.It is vertically faulted in the lower part and downwarped in the upper part.The Neogene strata are inclined to the South and few faults are developed in the basin.The Eocene middle deep lacustrine source rocks are mainly developed in the Yacheng 9 subsag,and the coal measure source rocks of the Yacheng formation are developed in the southeast of the sag.Finally,it is considered that the hydrocarbon source in the Yabei sag has the characteristics of"oil in the West and gas in the East".The western and southwest slopes of the sag and the steep slope Paleogene traps near the Yacheng9 subsag are the direction of oil exploration;however,the natural gas exploration prospect of the concave uplift and surrounding traps in the southeast of the depression is good.

关 键 词：油气勘探潜力 断裂特征 底辟 崖北凹陷 琼东南盆地 

分 类 号：P736.213[天文地球—海洋地质]