摘要
致密储层岩石渗透率低,储集空间受其微纳米级孔隙控制,毛管力作用显著增强。认识油气的微观充注特征是分析运聚成藏的基础。利用自研的岩心流体驱替在线三维显微成像系统,开展致密储层样品油充注过程观测,提出样品整体和孔隙两级的含油特征综合定量分析方法。以相同流程的驱替在线核磁共振测试为对照,揭示不同时刻在线二维直接数字化摄影(Digital Radiography,DR)的平均差值,可用于评价样品整体含油量变化;基于高精度孔隙网络抽提的孔隙级流体饱和度计算方法,实现了图像可分辨的孔隙与孔喉油充注程度的定量评价。通过多层次数据、不同方法的组合,可满足不同研究对动态特征捕捉、孔隙分辨能力及成像视野等差异化需要。分析结果表明,鄂尔多斯盆地不同致密储层两块岩石样品的含油饱和度随注油量的增加,均呈现开始上升较快、后期减缓的特点;相同注入流速下,相对高渗样品油充注初期含油饱和度上升速度更快,最终含油饱和度较高;随着注油量的增加,较高渗样品的大孔隙含油饱和度持续增加,低渗样品大孔隙的含油饱和度呈U形变化,表现出油、水反复占据孔隙的特点。
The reservoir space of tight reservoir with low-permeability is controlled by micro and nano scale pores,making the influence of capillary force significantly enhanced.Therefore,understanding the microscopic charging characteristics of oil and gas is the basis for analyzing the migration and accumulation of reservoirs.In this paper,the self-developed on-line three-dimensional microscopic imaging system for core fluid displacement is used to observe the oil charging process of two tight reservoir samples,and core-level and pore-level quantitative analysis methods for oil content characteristics are proposed.Taking the on-line nuclear magnetic resonance testing with the same process of displacement as a contrast,it is revealed that the average difference of on-line 2D DR(Digital Radiography)images at different times can be used to evaluate the overall oil content change of the sample.The calculation method of pore level fluid saturation based on high-precision pore network extraction algorithm realizes the quantitative evaluation of oil charging degree of the CT resolved pores and pore throats.The combination of multi-level data and different methods can meet the different needs of different researches on dynamic feature capture,pore resolution and imaging field of vision.The analysis results show that the oil saturation of two rock samples from different tight reservoirs in the Ordos Basin increases rapidly at the beginning and slows down later with oil injection increasing.At the same injection flow rate,the oil saturation of the sample with higher permeability increases faster at the initial oil charging stage,making its final oil saturation higher.With the increase of oil injection,the oil saturation of macropores in the sample with higher permeability continuously increases,while that of macropores in the sample with lower permeability shows a U-shaped change,showing the characte-ristics of repeated occupation of pores by oil and water.
作者
江文滨
林缅
姬莉莉
曹高辉
张立宽
窦文超
郑思平
陈卓
邱鑫
JIANG Wenbin;LIN Mian;JI Lili;CAO Gaohui;ZHANG Likuan;DOU Wenchao;ZHENG Siping;CHEN Zhuo;QIU Xin(Key Laboratory for Mechanics in Fluid Solid Coupling Systems,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;School of Engineering Science,University of Chinese Academy of Sciences,Beijing 100190,China;Key Laboratory of Oil and Gas Resources Research,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)
出处
《石油实验地质》
CAS
CSCD
北大核心
2023年第2期366-377,共12页
Petroleum Geology & Experiment
基金
中国科学院A类战略性先导科技专项(XDA14010304)
国家自然科学基金项目(42030808,41690132和41872163)
中国科学院仪器设备功能开发技术创新项目(2020BA19)联合资助。
关键词
在线显微成像
油充注
直接数字化摄影
孔隙网络
致密储层
on-line microscopic imaging
oil charging
Digital Radiography(DR)
pore network
tight reservoir
