High-yielding oil wells were recently found in the first member of Paleogene Shahejie Formation, the Binhai area of Qikou Sag, providing an example of medium- and deep-buried high-quality reservoirs in the central part of a faulted lacustrine basin. By using data of cores, cast thin sections, scanning electron microscope and physical property tests, the sedimentary facies, physical properties and main control factors of the high-quality reservoirs were analyzed. The reservoirs are identified as deposits of slump-type sub-lacustrine fans, which are marked by muddy fragments, slump deformation structure and Bouma sequences in sandstones. They present mostly medium porosity and low permeability, and slightly medium porosity and high permeability. They have primary intergranular pores, intergranular and intragranular dissolution pores in feldspar and detritus grains, and structural microcracks as storage space. The main factors controlling the high quality reservoirs are as follows: (1) Favorable sedimentary microfacies of main and proximal distributary gravity flow channels. The microfacies with coarse sediment were dominated by transportation and deposition of sandy debris flow, and the effect of deposition on reservoir properties decreases with the increase of depth. (2) Medium texture maturity. It is shown by medium-sorted sandstones that were formed by beach bar sediment collapsing and redepositing, and was good for the formation of the primary intergranular pores. (3) High content of intermediate-acid volcanic rock detritus. The reservoir sandstone has high content of detritus of various components, especially intermediate-acid volcanic rock detritus, which is good for the formation of dissolution pores. (4) Organic acid corrosion. It was attributed to hydrocarbon maturity during mesodiagenetic A substage. (5) Early-forming and long lasting overpressure. A large-scale overpressure compartment was caused by under-compaction and hydrocarbon generation pressurization related to thick deep-lacustrine mudstone, and is responsible for the preservation of abundant primary pores. (6) Regional transtensional tectonic action. It resulted in the structural microcracks.

最近在齐口凹陷滨海地区古近系沙河街组的第一段发现了高产油井，为断层湖盆中部的中深层优质油藏提供了一个例子。利用岩心，铸件断面数据，扫描电镜和物性测试，分析了优质储层的沉积相，物性和主要控制因素。储层被确定为坍落型湖底扇沉积物，其特征是泥岩中的泥屑碎片，坍落变形结构和Bouma序列。它们主要表现出中等孔隙率和低渗透率，略有中等孔隙率和高渗透率。他们有主要的晶间孔，长石和碎屑颗粒的粒间和粒内溶解孔以及结构微裂纹作为储藏空间。控制优质储层的主要因素如下：（1）主，近端重力流道的有利沉积微相。含沙质泥沙的微相主要由砂质泥石流的输运和沉积所控制，沉积对储层物性的影响随深度的增加而减小。（2）中等质地成熟度。它由中型砂岩显示，这些砂岩是由滩坝沉积物的塌陷和再沉积形成的，有利于形成主要的粒间孔。（3）中酸性火山岩碎屑含量高。储层砂岩中各种成分的碎屑含量高，尤其是中酸性火山岩碎屑，对形成溶蚀孔隙有利。（4）有机酸腐蚀。这归因于中成岩作用A阶段的烃成熟度。（5）早期形成和持久的超压。大型超压隔室是由与厚深湖相泥岩有关的欠压实作用和烃类产生的增压作用所致，并负责保存大量的初级孔隙。（6）区域性张性构造作用。这导致了结构微裂纹。大型超压隔室是由与厚深湖相泥岩有关的欠压实作用和烃类产生的增压作用所致，并负责保存大量的初级孔隙。（6）区域性张性构造作用。这导致了结构微裂纹。大型超压隔室是由与厚深湖相泥岩有关的欠压实作用和烃类产生的增压作用所致，并负责保存大量的初级孔隙。（6）区域性张性构造作用。这导致了结构微裂纹。