Based on the analysis of the growth process of the southern boundary fault (FS), the location, type and characteristics of transfer zone developed at the Su south steep slope zone was studied. The control of this transfer zone on the sandbodies deposition at the steep slope zone during the Abu Garba syn-rifting period and the prediction of favorable area for forming lithological reservoirs as well as their accumulation model were also analyzed. Result shows that Southern boundary fault was composed by two segment faults and a synthetic transfer zone between two adjoining segment faults developed along this fault. This zone has an obvious impact on the the sandbodies depositing at the steep slope belt during Abu Gabra syn-rifting period, Sand ratio has an abnormally higher value in the position close to the transfer zone than that developed far away from transfer zone. The mode of transfer zone controlling the sandbodies deposition could be divided into two types. There is a potential favourable area for exploring the lithogical reservoirs at the steep slope belt, which is close to the hydrocarbon generation and expulsion center, located in the updip direction of the transverse anticlines and on the paths of oil and gas secondary migration.

基于渤海湾盆地牛庄洼陷的3D地震精细构造解释成果,本文揭示了伸展盆地内部正断层由旋转正断层向连通的铲式正断层递进演化过程,该演化过程划分为4个阶段:以旋转平面型正断层为主要类型的初始阶段,以多米诺断阶为主要类型的发展阶段,以单条独立铲式正断层为主要类型的成熟阶段以及以连通铲式正断层为主要类型的高成熟阶段;并建立了在伸展量的递进增加且浅层存在滑脱层的地质条件下,旋转平面型正断层向铲式正断层递进演化模式.通过分析研究区剖面伸展量数据以及系列断层断距的变化,认为伸展量在不同级别断裂(主干断裂与次级断裂)之间的分配方式是研究区该递进演化过程的主控因素.本文提出的伸展盆地内部正断层递进演化过程及其模式将有助于丰富与完善伸展盆地正断层递进演化理论,同时也可为伸展量较大的背景下,正断层样式演化程度较低的现象提供一种新的成因解释.

West and Central African superimposed rift basins are Meso-Cenozoic multicycle intra-continental rift basins developed on the Precambrian crystalline basement. Previous studies mainly focused on the formation and superimposition process of several prototype basins developed in a single superimposed basin, but it is rarely documented that research on the different contemporaneous complex superimposed rift basins in the same tectonic region as well as those superimposed rift basins with different prototypes basins in vertical through time has been carried out. Based on the geological, geophysical, and geochemical data obtained during the oil and gas exploration activities in the West and Central African superimposed rift basins recently, combined with the previous research results, this paper focuses on the basin evolution, formation and superimposition process of prototype basins through time of the West and Central African superimposed rift basins. Results show that since the breakup of Gondwana, affected by the relative movements among the Northwest African block, the Northeast African block, and the Central and South African block of the African continent and the tectonic events of the surrounding plates, the West and Central African superimposed rift basins have roughly experienced three phases of tectonic evolution, namely, Early Cretaceous, Late Cretaceous and Paleogene-Neogene. Early Cretaceous evolution phase is the key period of the formation and evolution of the rift basins, during which the boundary faults of these rift basins develop and act intensively. Three types of prototype basins are developed, including rift basin, strike-slip pull-apart basin and aulagu basin. Basement subsidence of these rift basins is the largest with the fastest subsidence rate among the total subsidence. Lower Cretaceous sedimentary filling has the largest percent in the total filling, and sedimentary systems in whole rifts system are non-marine elastic deposition. During Late Cretaceous evolution phase, these early prototype basins were inherited. However, the difference in rifting and the sedimentary filling among those rift prototype basins become larger. The Early Cretaceous sedimentary system also evolved into a marine-continental sedimentary system. During Paleogene-Neogene, the evolution of West and Central African superimposed rift basins became more complex, and the difference was further intensified. The rifting, strike-slip and compression-reversion occurred simultaneously in different basins, during which the rift prototype basins or inversion deformation developed. According to the differences in prototype basin type, sedimentary filling and vertical superimposition of the prototype basins in these three phases, these superimposed rifts in Central and Western Africa are divided into two types, inherited superimposed basins and reversed superimposed basins. They are further divided into eight subtypes, namely, early-developed superimposed basins, successive superimposed basins, dynamic superimposed basins, late-developed type I superimposed basins, late-developed type II superimposed basins, and rift-inverted superimposed basins, aurora-inverted superimposed basins, and strike-slip-inverted superimposed basins. The characteristics of different types of superimposed basins are discussed. These results are of great significance for deepening the understanding of the geological evolution of superimposed rift basins and guiding the search for favorable oil and gas enrichment areas and exploration activities in such basins worldwide.

中西非叠合裂谷盆地是发育在前寒武系结晶基底之上的中-新生代多旋回陆内裂谷盆地,以往的研究主要针对跨不同世代、不同性质原型盆地叠合构成的盆地,但对于由多期裂谷活动形成的叠合裂谷盆地,其叠合改造模式及其动力学机制研究尚不深入.本文基于近年来在中西非裂谷系油气勘探开发中获得的有关地质、地球物理和地球化学资料,结合前人研究成果,重点研究了中西非裂谷系盆地演化阶段、不同阶段原型盆地发育特征、多期叠合、改造类型、模式及其动力学背景.研究表明,自冈瓦纳大陆裂解以来,受非洲大陆周缘板块构造事件及西北非陆块、东北非陆块和中南非陆块间相对运动的影响,中西非裂谷系盆地大致经历了早白垩世、晚白垩世、古近纪-新近纪三个构造演化阶段.早白垩世阶段断裂活动最为强烈,是裂谷盆地主干断裂形成时期,在不同构造部位发育了裂谷盆地、走滑-拉分盆地和坳拉谷盆地三类原型盆地,盆地基底沉降速率最大,地层沉积充填厚度大,沉积体系均为陆相碎屑沉积,奠定了裂谷盆地形成演化的基础;晚白垩世阶段,早白垩世原型盆地继承发展,但盆地间裂谷发育程度差异性凸显,沉积充填特征差异变大,由早白垩世统一陆相沉积体系演变为海、陆相并存的沉积体系;古近纪-新近纪阶段,该裂谷系盆地发育变得更为复杂,差异性进一步加剧,裂谷作用、走滑作用和挤压反转作用在不同盆地同步发生,期间可持续发育裂谷盆地或发生挤压反转和构造变形.根据三个阶段原型盆地在盆地性质、沉积充填、垂向叠加、构造变形等方面的差异,将中西非叠合裂谷盆地划分为"继承叠合型"和"反转改造型"两类,进一步划分为"早断型"、"继承型"、"叠加型"、"晚断Ⅰ型"、"晚断Ⅱ型"以及"裂谷盆地反转型"、"走滑-拉分盆地反转型"、"坳拉谷盆地反转型"八种,并讨论了不同类型叠合盆地特征及其动力学背景.这些成果对于深化裂谷盆地形成演化地质认识,指导在全球该类盆地中优选油气有利富集区和油气勘探均具有重要意义.