摘要
中非西部多瑟欧盆地西部隆起构造带和东部反转背斜Ⅲ、Ⅳ次级构造带广泛发育特征明显不同的花状反转构造,但目前对于这些花状反转构造类型的归属、演化进程及其与油气成藏关系的认识尚不清晰。为此,利用钻井、测井、地震等多种资料,采用平衡剖面、构造与油气成藏等分析技术开展了综合研究。研究结果表明:①早白垩世纽康姆—巴雷姆期,盆地为伸展断陷发育期,盆地结构构造及规模已具雏形;②东部反转背斜Ⅲ、Ⅳ次级构造带为受走滑断层F1、F2控制的花状反转构造带,其上广泛发育一种非常规的正花状反转构造,突出表现在花状构造向上发散部分以小型正断层为主,但地层形态却呈现为背形,而西部隆起构造带则发育大型常规正花状反转构造;③盆地经历了伸展断陷—走滑—拗陷3个大的演化阶段,在拗陷阶段又经历了3幕构造反转,正花状反转构造演化进程突出表现为短断长拗、强伸展—走滑、3幕脉冲式西强东弱反转特征;④构造反转活动控制着正花状反转构造和相应圈闭的发育和分布;⑤位于东部反转背斜Ⅲ—Ⅳ带上的正花状反转构造型圈闭可划分为源内成藏和源上成藏2种模式,并具有圈闭形成时间—有效烃源岩生排烃高峰—构造反转幕次—断层再活动时间匹配良好之特点。
Characteristically distinct flower reversal structures are widely observed in the structural zones in the western uplift and the III and IV secondary structural zones in the eastern reversal anticline of Doseo Basin,western Central Africa.However,these structures are indefinite in types,evolution process and relation with hydrocarbon accumulation.Based on drilling,logging and seismic data,a systematic study was conducted through analyzing equilibrium profiles,structures and hydrocarbon accumulation.Results show that(i)in the Early Cretaceous Neocomian–Barremian,the basin developed as an extensional rift,with its structural configuration and scale shaped initially;(ii)the III and IV secondary structural zones in the eastern reversal anticline are flower-shaped reversal structures controlled by strike-slip faults F1 and F2,and above them are the widespread development of an unconventional positive flower reversal structures.The prominent manifestation is that the upward divergent part of the flower shaped structure is mainly composed of small normal faults,but the geological morphology presents an antiform,while the western uplift structural belt develops large conventional positive flower reversal structures;(iii)the structural zones in the western uplift develop large-scale conventional positive flower reversal structures.The basin has evolved primarily in three stages:extensional rift,strike-slip,and depression.During the depression stage,it has also undergone three episodes of structural inversion.The evolution process of positive flower reversal structures are predominantly characterized by short rifting and long depression,strong extension–strike-slip,and three episodes of impulse reversion strong in the west and weak in the west;(iv)structural reversion activities controlled the development and distribution of positive flower reversal structures and associated traps;and(v)the traps of positive flower reversal structures at the III and IV secondary structural zones in the eastern reversal anticline are categorized into inner-source and above-source hydrocarbon accumulation models,and show good matches in terms of trap-formation time,peak hydrocarbon generation and expulsion of effective source rocks,episodes of structural reversion,and fault reactivation time.
作者
张懿
郑求根
ZHANG Yi;ZHENG Qiugen(Shanghai Branch of CNOOC(China)Co.,Ltd.,Shanghai 200335,China;School of Ocean Sciences,China University of Geosciences(Beijing),Beijing 100083,China)
出处
《天然气勘探与开发》
2025年第4期41-49,共9页
Natural Gas Exploration and Development
基金
中国石油股份有限公司前瞻性基础性项目“海外重点含油气盆地评价与勘探关键技术研究”(编号:2021DJ31)。
关键词
中非剪切带
多瑟欧盆地
正花状反转构造
演化进程
油气成藏
生储盖组合
Central African shear zone
Doseo Basin
Positive flower reversal structure
Evolution process
Hydrocarbon accumulation
Source-reservoir-cap combination
作者简介
张懿,男,1992年生,工程师,硕士,主要从事东海海域油气勘探与开发研究工作。地址:(200335)上海市长宁区北新泾街道通协路388号。E-mail:zhangyi78@cnooc.com.cn。
