十屋断陷异常高孔带分布特征及成因

An analysis of abnormal high porosity zone distribution and origin in reservoir rocks in Shiwu fault depression

深层碎屑岩储层岩性致密、物性较差,寻找孔渗性较好的异常高孔带是深层勘探的重要目标.利用岩心的实测孔隙度、普通薄片和铸体薄片资料对十屋断陷深层碎屑岩岩石学特征和物性纵向分布特征进行了研究.结果表明,十屋断陷碎屑储层发育3个异常髙孔带,纵向分布范围分别为400～800m、1200～1800m、2200～2700m;大量沉积学研究和成岩参数测试分析结果表明,高孔带的形成主要受成岩作用的控制;第Ⅰ高孔带主要由大气水淋滤作用形成,第Ⅱ、Ⅲ高孔带主要由有机酸及黏土矿物脱酸性水的溶蚀作用形成.该预测结果为研究区深层油气勘探提供了科学依据.

The compact lithology and poor physical property is characteristic of the clastic rock reservoir in the deep zone.Searching the zone with anomalously high porosity is an important aim of the exploring in the deep zone.The data,such as measurement porosity of the core,logging porosity and cast thin section,are used to analyze the petrological characteristic and distribution and origin of abnormal high porosity zones in reservoir rocks in the Shiwu fault depression.Vertically,there are three abnormal high porosity zones in the reservoir rocks:400~800 m、1 200~1 800 m、2 200~2 700 m.Many researches about sedimentology and the analytic result of the diagenetic parameters testing show that the diagenesis controls the formation of the high porosity.The first high porosity zone is formed by the eluviation.The denudation by which the acidic water of organic acid and clay mineral are dehydrated has formed the second high porosity zone and the third high porosity zone.The prediction result provides scientific foundation for the additional exploration of the region.