箕状断陷控洼断裂上下盘油气成藏差异性及勘探实践——以南海北部珠江口盆地惠州凹陷X洼为例  

Difference of Hydrocarbon Accumulation Between Hanging and Foot Wall of Half Graben Boundary Fault and Exploration Practice:A Case Study of X Sag in Huizhou Depression,Pearl River Mouth Basin,Northern South China Sea

作　　者：姜大朋 何敏 张向涛 彭光荣 牛胜利 李振升 Jiang Dapeng;He Min;Zhang Xiangtao;Peng Guangrong;Niu Shengli;Li Zhensheng(Shenzhen Branch of CNOOC Ltd.,Shenzhen 518054,Guangdong,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518054

出　　处：《吉林大学学报（地球科学版）》2019年第2期346-355,共10页Journal of Jilin University：Earth Science Edition

基　　金："十三五"国家科技重大专项(2016ZX05024-004)~~

摘　　要：箕状断陷是中国东部陆架边缘盆地常见的洼陷样式,其陡坡带是有利的油气成藏区带之一。控洼边界断裂对于陡坡带油气成藏具有明显控制作用。断裂带内部结构导致下盘油气成藏模式不同于上盘。以珠江口盆地惠州凹陷X洼控洼边界断裂(X断裂)为例,分析认为其为一条长期继承性活动的大断层,发育完善的破碎带和断层核二元结构,并以此为基础分析了X断裂对下盘油气成藏的控制作用及其与上盘的差异。采用定性+定量的方法评价认为,X断裂发育连续的致密断层岩,在主要目的层具有良好的侧向封闭性;导致两盘成藏差异的是断层垂向封闭性。X断裂下盘油气成藏的运移方式异于上盘,由于断层核的遮挡,油气并不是直接充注圈闭,而是通过断层末端或者转换带的连通砂体以类似于螺旋楼梯式的方式运移至下盘。综合认为,X洼下盘断圈构造具有勘探潜力并得到了钻井证实。Half graben is a common sag pattern in the continental margin basins in East China,and its steep slope zone is one of the favorable oil and gas accumulating areas.Boundary faults play an important role in controlling the accumulation of oil and gas in steep slope zones.The internal structure of fault zone leads to different oil and gas accumulation models in footwall from those of hanging wall.Taking the X sag boundary fault in Huizhou depression of PRMB as an example,which is a long-term active fault developed with complete binary structure of fracture zone and fault core,we analyzed the control difference of the fault on oil and gas accumulation in the footwall and hanging wall.By means of qualitative and quantitative methods,we considered that the X fault developed continuous compact fault rocks with good lateral sealing in the main target layers;the vertical sealing of faults resulted in the difference of reservoir formation between the two pans;the migration of oil and gas into the reservoir of X fault footwall was also different from that of the hanging wall;because of the shielding of fault core,oil and gas were not directly charge in traps,but migrated to the footwall through connected sand bodies at the end of the fault or the transition zone in a manner similar to spiral staircase.In a word,the fault controlled structure in the X fault footwall has exploration potential,and which has been proved by drilling.

关 键 词：惠州凹陷 箕状断陷 控洼断裂 上下盘 断裂带内部结构 转换带运移 

分 类 号：P618.13[天文地球—矿床学]