歧口凹陷沙南低凸起的幕式构造活动及对沉积过程的控制

渤海湾盆地的海域部分勘探程度较低,歧口凹陷东西两侧构造幕次认识仍有争议.位于盆地中的掀斜凸起对断陷盆地幕式构造活动有较好的动力学响应.以新三维地震资料为基础,应用平衡剖面、断层生长指数等研究手段,对渤海海域西部、歧口凹陷东部的沙南低凸起的构造演化进行详细的解剖.研究表明沙南低凸起在古近系曾经发生过两次隆升、三次沉降;断层生长指数与平衡剖面显示东三时期沙南低凸起曾经强烈活动,反映出这一地区东营组沉积时期是一个构造幕的开始.隆升的低凸起分割了湖泊水系,并为其周围地区提供了间歇性物源.沙南低凸起北部的砂质滩坝、近岸水下扇等砂体易于形成岩性地层油气藏,具有很好的油气勘探潜力.

The Tectonic Movement of ShaNan low salient and its influence to sedimentary process in the north Qikou depression of Bohai Bay Basin

The sea area of the Bohai bay basin is in low exploration degree. The understanding of tectonic phase on both east and west sides of qikou depression is still in dispute. The tilting salient in the basin has a good dynamic response to the episodic tectonic movement of fault basin. In this paper , detailed analysis of tectonic evolution on ShaNan low salient of eastern Qikou sag in western bohai sea is proposed, based on the new 3D seismic data and the application of research means ,such as balanced section technique and fault growth index and so on. Research shows that ShaNan low salient once had two times of uplift and three times of settlement. Fault growth index and balanced section shows that ShaNan low salient once had a strong activity in Ed3, which reflects that Dongying Member deposition in this area is the beginning of a tectonic phase. The uplift of the low salient segments the lake and provides intermittent provenance for surrounding area. Sandy beach-bars and nearshore subaqueous fans in northern ShaNan low salient are apt to form stratigraphic and subtle reservoirs with good hydrocarbon exploration potential.