沧东凹陷南皮斜坡孔二段沉积特征与油气勘探

Sedimentary characteristics and hydrocarbon exploration of Ek^2 of Nanpi slope area,Cangdong sag,Huanghua depression,North China

应用沉积学和石油地质理论,通过沉积背景分析、岩心观察、砂分散与油气成藏模式构建等手段,对黄骅拗陷沧东凹陷南皮斜坡古近系孔店组第二段(孔二段)沉积特征与控砂控藏模式进行了研究,认为南皮斜坡是一个继承性发育的缓坡,孔二段受东光凸起、沧县隆起物源及徐黑凸起物源的影响,斜坡砂体发育,且具有凸起顺向供砂、侵蚀沟槽输砂、单一坡-折控砂的规律,以发育辫状河三角洲-远岸水下扇沉积为主。中斜坡发育三角洲前缘主体,埋藏适中,储集物性好,砂岩与烃源岩匹配,圈闭条件良好,且位于油气运移的有利指向区,是岩性地层油气藏勘探的重点领域;低斜坡发育优质烃源岩,夹三角洲前缘远端-远岸水下扇砂体及薄层的云质岩类,是致密油勘探的有利地区。

Using sedimentology and petroleum geology, based on the analysis of sedimentary background,the core observation,the sand distribution and by building the hydrocarbon accumulation patterns,this paper studies the sedimentary characteristics and the models of controlling sand and oil reservoirs in Member 2 of Paleogene Kongdian Formation （Ek^2 ）of the Nanpi slope area,Cangdong sag of the Huanghua depression. The researches show that the Nanpi slope is a successively developing gentle slope.Because the influence of the provenance from the Dongguang salient,the Cangxiang uplift and the Xuhei salient,the sand bodies are well-developed in Ek^2 .In the pattern that the sand bodies are supported forward from the salient,transported in erosion grooves,and controlled by the single slope-break,there mainly develops the braided river delta-off shore subaqueous fan. There mainly develop the bodies of delta front in the middle slope,where the sand bodies matching the source rocks are buried in a moderate depth,have better physical properties,at the same time,have good trap conditions,and are located in the favorable directional zone of hydrocarbon migration.So the middle slope is the important exploration area of lithostratigraphy reservoir.In the low slope, there develop the superior source rocks which are intercalated with the sand bodies formed by far delta front-off shore subaqueous fan and the thin dolomite.So the low slope is the favorable exploration area of tight oil.