临清坳陷中晚二叠系储层沉积结构及演化

临清坳陷是我国东部重要的油气资源研究区.采用储层沉积学、地层学及石油地质学等多种学科研究方法,对临清坳陷煤成气储层沉积结构特征及储层砂体空间分布进行研究,在此基础上总结了典型储层沉积体系和沉积相的空间分布,这对于该区油气资源勘探具有重要意义.研究结果表明：该区中晚二叠世是陆表海盆地由海相向陆相沉积转换的后期,因此主要沉积体系以大型河控浅水三角洲沉积体系和河流-湖泊复合沉积体系为主.临清坳陷二叠系储层砂体沉积结构可分为4种典型类型,为河床滞留相与泛滥平原相组合(CL-FP)、边滩相与天然堤相组合(PB-NL)、分流河道相与分流间湾相组合(DC-IB)和决口扇相与泛滥平原相组合(CV-FP).全区储层沉积砂体呈现一定不均性,中二叠系砂体较厚,向西北、西南方向变薄.晚二叠系砂体局部地区厚度很大,呈现东西厚中间薄特点,成为该区最好的储层砂体.研究结果为该区煤成气资源下一步勘探主要目标提供指导意义.

Sedimentary structure and evolution of middle-late permian reservoir at Linqing depression

Linqing depression is an important research area of the oil and gas resources in east china. The reservoir sedimentology, stratigraphy and petroleum geology as the main research means was taken. The sedimentary structure of coal-formed gas reservoir and the spatial distribution of the reservoir sandstone at Linqing depression were researched. And the typical reservoir sedimentary system and the spatial distribution of the sedimentary facies were summarized, which have an important meaning to the oil and gas resources exploration of the area. The findings indicate that late Permian is at the later time of the sedimentary facies conversion of the epicontinental sea basin from marine sedimentation to continental sedmimentation. So the main sedimentary systems are the large-scale fluvial-controlled shallow-water deltaic depositional system and the composite sedimentary system of rivers and lakes. The sedimentary structure of the permian reservoir sand body in Linqing depression is divided into four typical types: the combined of the riverbed lag facies and the flood plain facies (CL-FP), the combined of the point bar facies and natural levee facies (PB-NL), the combined of the distributary channel facies and the distributary interchannel facies (DC-IB), the combined of the crevasse splay facies and the flood plain facies (CV-FP). The sandstones as reservoir show ununiformity character, the middle Permian sand body is thicker, which becomes thin to the northwest and southwest direction. The thickness of the late Permian sand body is big in some areas, the characteristic of the central area is thinner while the east and west part is thicker is presented, which becoming the best reservoir sand body of the area. The research results offer the guide for the further exploration of the coal gas resources in this area.