饶阳凹陷马西地区古近系层序地层与隐蔽油气藏勘探

利用地震、测井、岩相等资料,对饶阳凹陷马西地区古近系进行了层序地层学研究,将其划分为3个二级层序和10个三级层序。层序Ⅷ、Ⅸ、Ⅹ为河流层序,可划分为基准面上升体系域和基准面下降体系域;层序Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ和Ⅶ为湖泊层序,每个层序可划分为低位体系域、湖侵体系域和高位体系域。在层序地层研究的基础上,认为马西地区同沉积构造坡折带的存在控制了砂体的展布、烃源岩的发育以及油气的运聚,因而对该地区隐蔽油气藏的形成起控制作用。建立了隐蔽油气藏在不同体系域中的发育模式,并提出了下一步勘探的有利方向。

Palaeogene sequence stratigraphy and subtle hydrocarbon exploration in the Maxi region,Raoyang depression,Hebei

The Palaeogene sequence stratigraphy in the Maxi region, Raoyang depression may be classified, on the basis of seismic data, well logs and sedimentary facies, into 3 second-order sequences and 10 third-order sequences. The third-order sequences VIII, IX and X are assigned to the fluvial sequences including the base-level rising systems tract and base-level falling systems tract. The third-order sequences Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ, Ⅵ and Ⅶ represent the lacustrine sequences, each of which consists of lowstand systems tract, transgressive systems tract and highstand systems tract. The syndepositional structural breaks in the Maxi region have exercised a major control on the distribution of sandstones, development of source rocks, migration of hydrocarbons, and accumulation of subtle hydrocarbons in this region. The model for the accumulation of subtle hydrocarbons shows that Sequences Ⅲ, Ⅳand V below the structural breaks may be regarded as the targets for the further exploration of hydrocarbons.