高级检索

    辽河坳陷大洼地区中生界火山岩储层特征及成藏模式

    Characteristics and hydrocarbon accumulation models of Mesozoic volcanic reservoirs in the Dawa area of Liaohe depression

    • 摘要: 大洼地区毗邻大型生油洼陷—清水洼陷,多级断裂及多期不整合面构成复合油气输导体系,成藏条件优越。但本区火山岩储层岩性岩相复杂、喷发环境多变。为进一步明确储层发育特征及油气成藏主控因素,本次研究利用15口井107.73 m的岩心、270块薄片及测井资料综合分析,认为大洼地区Mz-Ⅰ段形成于水下喷发环境,发育溢流相玻质碎屑岩亚相玄武质火山角砾岩及溢流相熔岩亚相玄武岩;Mz-Ⅱ段形成于水上喷发环境,发育爆发相凝灰亚相流纹质凝灰岩及溢流相熔岩亚相安山岩。其中玄武质火山角砾岩储集性能最好,平均孔隙度19.3%,平均渗透率6.71×10-3 μm2,玄武岩物性最差,平均孔隙度9.2%,平均渗透率0.23×10-3 μm2。根据录测井及地震资料分析,认识到大洼地区中生界火山岩具有良好源储配置关系且发育多期次断裂及不整合面组成的复合油气输导体系。结合试油试采资料进一步确定油气藏的分布,明确成藏主控因素,建立油气成藏模式。研究表明,储层品质受控于岩性岩相、火山喷发环境及构造活动,油气成藏主要受控于源储配置关系及输导体系,油藏类型为构造-岩性复合型油藏,西侧近油源且近台安—大洼断层的有利岩性岩相带为有利勘探目标区。

       

      Abstract: The Dawa area is adjacent to the Qingshui large oil-generating sag, where the composite hydrocarbon migration system constituted by multi-stage faults and unconformities provides a favorable condition for hydrocarbon accumulation. However, the volcanic lithology and lithofacies are complex with changeable eruption environment in this area. In order to clarify the reservoir characteristics and the main controlling factors of hydrocarbon accumulation, based on 107.73 m core, 270 thin sections and logging data from 15 wells, the volcanic lithology and lithofacies are classified. It is suggested that the Mz-ⅠMember was formed in underwater eruption environment with overflow hyaloclastite subfacies basaltic volcanic breccia and overflow lava subfacies basalt. The Mz-Ⅱ Member was developed in abovewater eruption environment with explosive tuff subfacies rhyolitic tuff and overflow lava subfacies andesite. Among the volcanic lithofacies, the basaltic volcanic breccia shows the best physical property with porosity of 19.3% and permeability of 6.71×10-3μm2, and the basalt shows the worst physical property with porosity of 9.2% and permeability of 0.23×10-3μm2. Based on the logging and seismic data, it is recognized that the Dawa area possesses a favorable source-reservoir matching and composite hydrocarbon migration system constituted by multi-stage faults and unconformities. The hydrocarbon reservoir distribution is determined by production test data to definite the main controlling factors of hydrocarbon accumulation and establish accumulation models. The study shows that the reservoir quality is controlled by lithology, lithofacies, volcanic eruption environment and tectonic movement. The hydrocarbon accumulation is mainly controlled by source-reservoir configuration and migration system. The reservoir type is structural-lithologic composite reservoir. The favorable exploration target area is on the west side of the study area which develops favorable lithology and lithofacies and locates near oil source and Dawa fault. The west side of the study area and localities near oil source and Dawa fault are the priority prospects for exploration, where favorable lithology and lithofacies are developed.

       

    /

    返回文章
    返回