双清地区储层异常高孔带分布特征与成因分析

An analysis of abnormal high porosity zone distribution and origin in reservoir rocks in Shuangqing area,Liaohe depression

利用储层实测孔隙度、测井孔隙度以及铸体薄片等资料,研究了辽河坳陷双清地区储层异常高孔带的分布特征及成因。研究区储层纵向上发育3个异常高孔带,其形成主要受岩性、岩相和成岩作用的影响与控制。异常高孔带主要分布在扇三角洲和湖底扇的河口坝、水下分流河道、辫状分流沟道和前缘—外扇的砂体中,这些砂体均为结构成熟度和成分成熟度较高的长石砂岩;影响异常高孔带形成的成岩因素主要有大气水淋滤、有机酸溶蚀和粘土矿物脱水作用。双清地区储层异常高孔带的深度下限为3 850m,这也是该区油气勘探的深度下限。

The data, such as measured porosity,logging porosity and cast thin section, are used to analyze distribution and origin of abnormal high porosity zones in reservoir rocks in Shuangqing area, Liaohe depression. Vertically, there are three abnormal high porosity zones in the reservoir rocks, and their origin is mainly controlled by lithology, lithofacies and diagenesis. These porosity zones mostly developed in various lacustrine sandbodies, such as fan delta, mouth bar, subaqueous distributary channel, braided distributary channel and frontal-outer fan. All these sandbodies are composed of fine arkoses that are mature in texture and composition, in which the main diagenetic elements to affect formation of abnormal high porosity zones are meteoric water leaching, organic aid solution and clay mineral dehydration. The abnormal high porosity zones are not deep than 3 850 m in Shuangqing area, and it should be the deepest limit for petroleum exploration there.