沙湾凹陷与盆1井西凹陷构造过渡关系及地质意义

Tectonic Transition Relationship between Shawan Sag and Western Well Pen-1 Sag and Its Geological Significance

以地震和钻井资料为基础,结合构造地质剖面特征,应用断层相关褶皱理论,探讨沙湾凹陷与盆1井西凹陷过渡带的构造几何、运动特征。研究发现,沙湾凹陷与盆1井西凹陷过渡带存在古隆起,呈北西—南东向展布的不规则长条状;在此基础上,通过建立沙湾凹陷与盆1井西凹陷过渡带构造模型,认为古隆起基底为"隆起+半地堑"模式,受背冲式基底逆断层、伸展正断层共同控制,从中二叠世之后转变为"单独隆起"模式。古隆起的形成过程可分为晚石炭世—早二叠世的雏形期、中二叠世早期的发展期、中二叠世晚期的高峰期、晚二叠世—中侏罗世西山窑期的继承期以及中侏罗世末期—现今的改造期5个阶段。

Based on the seismic and drilling data and combining with geological sections, the paper discusses the the structural geometryand the characteristics of movement of the transitional zone from Shawan sag to the western Well Pen-1 sag by using fault-related fold theo-ries. The study shows that a paleohigh exists in the transitional zone, which exhibits a NW-SE trending, irregular strip. Based on which,through the structural model establishment of the transitional zone from Shawan sag to the western Well Pen-1 sag, it is considered that thebasement of the paleohigh had a pattern of＂uplift plus semi-graben＂and was controlled by both back-thrust reverse basement fault and ex-tensional normal fault, and changed to a pattern of＂sole uplift＂after the Middle Permian. The forming process of the paleohigh can be di-vided into 5 periods such as the prototype period from the Late Carboniferous to Early Permian, the development period at the early MiddlePermian, the peak period at the late Middle Permian, the inherited period from the Late Permian to Middle Jurassic and the reconstructionperiod from the end of the Middle Jurassic up to now.