摘要: |
基于铸体薄片分析、扫描电镜、高压压汞和核磁共振测试等试验结果,对姬塬油田长8油层组的微观孔隙结构进行研究,并建立目标储层的孔隙结构分类标准。通过选取每种类型储层有代表性的样品开展真实砂岩微观模型水驱油试验,进一步研究微观孔隙结构特征与驱油效率的关系。结果表明:研究区长8储层的孔隙类型以粒间孔和长石溶孔为主,喉道类型以弯片状喉道为主;目标储层孔隙结构可以划分为Ⅰ、Ⅱ、Ⅲ3种类型,3种类型孔隙结构对应的储集空间和渗流能力依次下降;不同类型储层间的注水驱替类型、驱油效率和残余油分布特征存在较大差异,Ⅱ类储层是未来挖潜的主要方向;影响驱油效率的因素是多方面的,其中可动流体饱和度、可动流体孔隙度是比其他物性参数更能反映与驱油效率之间关系的重要参数。 |
关键词: 致密砂岩 微观孔隙结构 可动流体饱和度 分类标准 驱油效率 |
DOI:10.3969/j.issn.1673-5005.2020.01.009 |
分类号::TE 311 |
文献标识码:A |
基金项目:陕西省自然科学基础研究计划项目(2019JQ-823,2018JM5017);中国石油科技创新基金项目(2019D-5007-0204);国家自然科学基金项目(51974254,51774236) |
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Micro pore structure and water-flooding characteristics on tight sandstone reservoir |
HUANG Xing1,2, GAO Hui1, DOU Liangbin1
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(1.School of Petroleum Engineering, Xi 'an Shiyou University, Xi 'an 710065, China;2.Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil & Gas Reservoirs, Xi 'an 710065, China)
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Abstract: |
In this study, the micro pore structures of Chang 8 reservoir in Jiyuan Oilfield were investigated via thin slice analysis of cores, SEM, high pressure mercury penetration and NMR testing, and the classification criteria of the pore structures of the target reservoir were established. The relationship between micro-pore structure characteristics and oil displacement efficiency was further studied by selecting representative core samples of each reservoir type to conduct water-flooding displacement experiments with real microscopic sandstone models. The results shows that the primary pore type of Chang 8 reservoir is intergranular pore and feldspar dissolution pore, and the primary throat type is of curved lamellar throat. The pore structures of the target reservoir can be divided into three types(typesⅠ,Ⅱ and Ⅲ), and their corresponding storage capacity and flow ability of the three types decrease successively from type I to type III. There are great differences among different reservoir types in terms of water-flooding type, oil displacement efficiency and distribution characteristics of the residual oil. The type Ⅱ reservoir is the main target for improved oil recovery in the future. There are many factors that affect oil displacement efficiency, among them the mobile fluid saturation is the most suitable parameter to reflect the relationship with oil displacement efficiency. It has been proven that the reservoir types classified by this method are accurate and adoptable, which can provide a basis for the effective exploration and development of Chang 8 reservoir. |
Key words: tight sandstone micro pore structure mobile fluid saturation classification criteria oil displacement efficiency |