西湖凹陷花港组储层综合分类方法探讨

Comprehensive Classification Scheme of Huagang Reservoir in Xihu Depression

以东海盆地西湖凹陷花港组主力储层为研究对象,以大量薄片、粒度、压汞和气水相渗等实验数据为基础,对花港组储层的岩性、物性和孔隙结构特征进行研究。认为花港组储层岩性以细砂岩为主,孔隙类型多样,孔隙结构较差,为低渗到超低渗储层。在储层特征研究基础上,重点探索利用储层动态渗透率与流动单元指数来表征储层的产能类别,共优选7大类储层参数,把储层划分为4大类,其中Ⅰ类、Ⅱ类储层具有自然产能,Ⅲ类储层则需进行压裂改造,Ⅳ类储层即使改造也效果较差,基本为无效储层。实际应用表明,本研究提出的花港组储层综合分类方案与实际测试结果基本吻合,推广应用前景良好。

This paper presents the lithology, physical properties, and pore structure of the Huagang reservoir based on a large experimental dataset of thin-section, granularity, mercury injection and gas-water phase permeability. The study shows that lithology of the Huagang Formation is dominated by fine sandstone with diverse pore types and poor pore structure, which constitutes a(ultra-)low-permeability reservoir. Based on the reservoir features, we focus on the use of reservoir dynamic permeability and flow unit index to categorize the reservoir capacity. Seven types of reservoir parameters are selected, and the reservoirs are divided into four categories, including Class Ⅰ and Ⅱ(with natural production capacity), Class Ⅲ(need to be fractured), and Class Ⅳ(ineffective reservoir). Practical application shows that the Huagang reservoir classification scheme proposed is consistent with the actual test results, and has good application potential.