周口坳陷北部凹陷构造演化及上古生界油气成藏探讨

周口坳陷北部凹陷构造相对较简单，是坳陷内部油气勘探的一个重要区域。以地震剖面详细分析解释为基础，将该区古生代以来的构造演化划分为5个阶段：早古生代稳定沉一抬阶段；晚古生代稳定沉降阶段；中生代隆起剥蚀阶段；古近纪断陷沉降阶段；新近纪坳陷沉降阶段。在构造演化史分析的基础上。结合研究区埋藏史图。认为上古生界沉积之后经历埋深、剥蚀、再埋深的过程．最终形成一系列断块。本溪组到下石盒子组的煤层段和暗色泥岩段作为该区主力烃源岩，自古近纪以来进入二次生烃阶段，并大量生成天然气。区内上古生界油气藏聚集类型多样，上古生界油气成藏模式分为3种：自生自储、新生古储和古生新储。

Discussion on tectonic evolution and hydrocarbon accumulation of Upper Palaeozoic formation in northern Zhoukou depression belt

The northern depression belt, characterized by simple tectonics, is one of the most profitable exploration targets in Zhoukou Depression. Based on the detailed interpretation of seismic profile, this region has experienced five evolutionary stages since Palaeozoic Era. They are early Palaeozoic stable subsidence and uplift stage, late Paleozoic stable subsidence stage, Mesozoic era uplift and erosion stage, Paleogene faulted and subsidence stage and Neogene depression subsidence stage. Combined with the analysis of structural evolution and burial history, Upper Palaeozoic formation experienced deep burial, extreme denudation, secondary deep burial and finally formed a series of blocks. Hydrocarbon source rock, coal and dark mudstone from Benxi Formation to Xiashihezi Formation have occurred secondary hydrocarbon generation and have generated large mass natural gases since Paleogene. There are several modes of oil and gas accumulation and three patterns of hydrocarbon accumulation in Upper Palaeozoic oil and gas accumulation in this region, which are source-reservoir, Cenozoic source-Paleozoic reservoir and Paleozoic source-Cenozoic reservoir types.