吴起地区延10段致密砂岩储层孔隙结构及分形特征  

Pore Structure and Fractal Characteristics of Yan 10 Tight Sandstone Reservoir in Wuqi Area

作　　者：刘阳 庞雄奇[1,2] 丁超[3] 陈迪 李敏[1,2] LIU Yang;PANG Xiong-qi;DING Chao;CHEN Di;LI Min(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;College of Geoscience,China University of Petroleum(Beijing),Beijing 102249,China;School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an 710065,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)地球科学学院,北京102249 [3]西安石油大学地球科学与工程学院,西安710065

出　　处：《科学技术与工程》2023年第29期12474-12483,共10页Science Technology and Engineering

基　　金：中海油深圳分公司重大生产科研项目(SCKY-2020-SZ-21)。

摘　　要：侏罗系延安组延10段为典型的致密储层,是非常规油气聚集的重要场所,孔隙结构复杂、非均质性强。为了厘清其孔隙结构特征和非均质性,选取延10段储层12块样品,借助高压压汞实验、常规物性测试、X射线衍射、铸体薄片鉴定和扫描电镜分析等技术手段,根据压汞曲线的形态和储层物性将储层划分为3种类型,分析孔隙结构特征,利用分形几何理论计算分形维数,研究非均质性,并讨论其地质意义。结果表明:由Ⅰ类储层到Ⅲ类储层,排驱压力依次增大,物性变差,孔隙结构变复杂。延10储层分形曲线存在明显的拐点,呈两段式,分形维数分别为D_(1)和D_(2),D_(1)大于D_(2),D_(1)为2.982 8~2.999 4,平均为2.993 9,D_(2)为2.454 7~2.746 4,平均为2.619 7,大孔喉的非均质性更强。延10储层中不同矿物组分含量的差异影响着储层的非均质程度,储层非均质程度的高低影响着储层物性的好坏和孔隙结构的复杂程度。Yan 10 of Jurassic Yan'an Formation is a typical tight reservoir.The tight reservoir is an important place for unconventional oil and gas accumulation,with complex pore structure and strong heterogeneity.In order to clarify the pore structure characteristics and heterogeneity,12 samples from the Yan 10 reservoir were selected for high-pressure mercury injection,routine physical property testing,X-ray diffraction,casting thin section identification,and scanning electron microscope.Three types of reservoirs were classified in terms of the shape of mercury injection curve and physical properties,and the pore structure characteristics were analyzed.The fractal dimension was calculated by using fractal geometry theory,the heterogeneity was studied,and the geological significance of fractal dimension was discussed.The results show that the displacement pressure increase sequentially,the physical properties become poor,and the pore structure becomes complex from Class Ⅰ reservoir to Class Ⅲ reservoir.There is an obvious inflection point in the fractal curve of Yan 10,presenting two-stage fractal characteristics.Two fractal dimensions of D_(1) and D_(2) are obtained.D_(1) is larger than D_2.D_(1) ranges from 2.982 8 to 2.999 4,with an average of 2.993 9.D_(2) ranges from 2.454 7 to 2.746 4,with an average of 2.619 7.The heterogeneity of large pore throats is stronger than that of small pore throats.The degree of reservoir heterogeneity is affected by difference of mineral component content.The reservoir physical properties and pore structure are affected by heterogeneity.

关 键 词：吴起地区 致密砂岩储层 高压压汞 孔隙结构 分形特征 

分 类 号：TE121[石油与天然气工程—油气勘探]