二连盆地层序地层样式及油气意义

依据凹陷的层序地层特征、结构类型、凝缩段发育程度、成油条件和勘探成效，对二连盆地内部３２ 个凹陷进行分类评价，最终把下白垩统划分为４ 个超层序、６ 个层序，建立了四类湖盆的层序地层样式。指出层序地层样式和湖盆发育类型控制生油凹陷的优劣和油气藏展布。继承型湖盆成湖期多，从而形成了多期凝缩段、多套生油层系和可供开采的商业性油藏，取得了较高的勘探成效（ 阿南、额仁淖尔、吉尔嘎朗图凹陷） ，它们均属有利生油凹陷。晚盛型凹陷虽然具有相当规模的湖侵体系域，但由于成湖期短，有机质演化程度低，生油潜量和勘探成效远不如继承型湖盆，只能列为较有利生油凹陷，进行择优钻探。早盛型和衰退型湖盆，由其缺乏有利于油气形成的沉积环境，最终使其成油条件较差，不能列为油气勘探的对象。

Type of stratigraphic sequence in Erlian basin and its significance in oil/gas exploration.

Based on the sequence stratigraphy character, textural type, development level of condensed section, oil generation condition and exploration effectiveness of the depression, 32 depressions in Erlian basin are classified and estimated, in the end, 4 supersequences and 6 sequences in the Lower Cretaceous series have been divided, sequence stratigraphy mode of the 4 types of lake basin have been set up. It is point out that good and bad of hydrocarbon depression and oil gas pool arrangement are controlled by mode of sequence stratigraphy and development type of lake basin. There are multiple lake basin formation periods in the inherited lake basin so as to form multiple shrinkage periods, multiple source formations and commercial gas/oil reservoirs for exploitation, to give a rater higher exploration efficiency (Anan, Eren Nur, Jargalangt sags). Although there are fairly developed region of lake transgression system in the prevail depression yet the lake basin forming period was rather short, accompanied by a low degree of evolution of organisms, and therefore the potential of hydrocarbons and exploration efficiency is far inferior to the above one. It can be classified as fairly favorable hydrocarbon generation sag and can be explored by selective drilling for exploration. Due to lack of the sedimentary conditions in early prevail and recession lake basins favorable conditions for hydrocarbon generation and thus the conditions of hydrocarbon generation are inferior, they cannot be considered as targets for oil/and gas exploration.