东非裂谷系东支油气成藏主控因素及勘探潜力

发布时间：2018-08-30 17:14

【摘要】：东非裂谷系东支是新生代形成的陆内裂谷盆地群,南洛基查盆地位于东支裂谷系肯尼亚地区北部,自2012年以来已相继发现8个油田,累计发现2C储量766 MMbbl。通过对南洛基查盆地地震、钻井等地质资料综合研究,厘清了其油气地质特征及成藏规律。作为小型箕状断陷湖盆,盆地具有西断东超构造特征,西侧陡坡带以形成构造—岩性复合圈闭为主,东侧缓坡带以断块构造圈闭为主。盆地沉积充填为河流—(扇)三角洲—湖泊沉积体系,呈现出初始裂陷期—扩张期—萎缩期旋回特征。盆地发育渐新统—下中新统和中—下中新统2套成藏组合。根据对南洛基查盆地已发现油气田的解剖,认为成熟烃源岩、有效储集层及成藏要素间的合理配置是东支裂谷系油气规模成藏的主控因素。结合重力、地震、沉积厚度等资料综合分析,认为凯里奥山谷盆地、图尔卡纳盆地西北陆上和凯里奥盆地同样具有良好勘探潜力,值得重点关注。
[Abstract]:The eastern branch of the East African Rift Valley system is a Cenozoic intracontinental rift basin group. The South Lokica Basin is located in the northern part of Kenya in the Eastern Branch Rift system. Since 2012, 8 oilfields have been discovered successively, with an accumulative 2C reserves of 766 MMbbl.. Based on the comprehensive study of seismic and drilling geological data in the Nanluojicha Basin, the oil and gas geological characteristics and reservoir forming laws of the basin are clarified. As a small grain-shaped faulted lacustrine basin, the basin has the characteristics of western fault-east superstructure, the west steep slope zone is dominated by the formation of tectonic-lithologic complex traps, and the east gentle slope zone is dominated by fault-block structural traps. The sedimentary filling in the basin is a fluvial (fan) delta-lacustrine sedimentary system, showing the characteristics of the initial rifting period, the spreading period and the shrinking period. The basin developed 2 sets of assemblages of Oligocene-Lower Miocene and Miocene-Lower Miocene. Based on the anatomy of the oil and gas fields found in the South Lokicha Basin, it is considered that the rational allocation of mature source rocks, effective reservoirs and reservoir forming elements is the main controlling factor for the formation of oil and gas reservoirs in the eastern branch rift system. Based on the comprehensive analysis of gravity, earthquake and sedimentary thickness, it is concluded that the Kailio Valley Basin, the northwestern land of Turkana Basin and the Kailio Basin also have good exploration potential and deserve to be paid more attention to.
【作者单位】：中国石油勘探开发研究院;
【基金】：国家油气重大专项(2016ZX05029) 中国石油天然气股份公司重大科技专项(2013E-0501)资助
【分类号】：P618.13

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