CO2近混相驱的关键科学问题与展望  

Prospects and key scientific issues of CO near-miscible flooding

作　　者：陈浩 刘希良[1,2] 贾宁洪 张可[3] 杨冉[2] 杨胜来 CHEN Hao;LIU Xiliang;JIA Ninghong;ZHANG Ke;YANG Ran;YANG Shenglai(State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum-Beijing,Beijing 102249,China;College of Safety and Ocean Engineering,China University of Petroleum-Beijign,Beiijng 102249,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,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)安全与海洋工程学院,北京102249 [3]中国石油勘探开发研究院,北京100083

出　　处：《石油科学通报》2020年第3期392-401,共10页Petroleum Science Bulletin

基　　金：国家自然基金青年基金(51704303)资助。

摘　　要：CO2驱是一种具有广阔前景的提高油藏采收率的方法。自上世纪60年代以来,诸多学者对CO2驱进行研究,开展了多项室内实验和矿场试验。CO2注入对原油的影响非常复杂,主要包括:溶解、膨胀、降粘、扩散和传质等,各机制相互耦合、协同作用。原油组成不同,微观上各机理所起作用各异。另外,杂质气体的混入、水盾对油气体系的分隔以及孔隙尺度效应的存在,加剧了各微观机理作用机制的差异。本文综述了当前国内外CO2驱油现状,并结合油气勘探开发的实际需求,阐述了CO2驱油技术在油田推广应用的现状和问题。目前,对于CO2驱油的研究以及现场应用对最小混相压力过度关注,使得能否实现混相成了油田实施CO2驱油的决定因素。许多具有优势条件的油藏,仅仅因为无法达到最小混相压力而被否决。因此,针对工程实践更易实现的CO2近混相驱技术,提出了限制其发展的三大主控因素,探讨并展望了该技术未来的应用前景和发展方向。室内实验和矿场试验已充分证明了CO2近混相驱技术在改善油田开发效果方面的优势。较低的注入压力和操作成本,明显放宽了传统混相驱技术对我国普遍存在的储层条件、原油品质和气源匮乏等的限制。然而,近混相的定义并未完全统一,压力区间的确定方法仍属空白,典型特征和驱替机理尚未明确。实际应用过程中,"杂质气体混入"、"水盾阻隔"及"孔隙尺寸效应"对近混相的影响不可避免。非纯条件下产出气中CO2的浓度下限如何确定,油、气、水三相条件下的绕流、错流和马格朗尼流等不同形式的水盾阻隔效应如何表征,润湿性、孔隙分布和孔隙尺寸效应如何影响混相程度,各因素之间如何协同作用等诸多问题,亟待开展深入研究,以应对我国CO2近混相驱技术在推广和应用过程中的关键科学问题和随之而来的工程问题。CO2 flooding is a promising enhanced oil recovery(EOR) method. Since the 1960s, many scholars have conducted studies of CO2 flooding, including laboratory experiments and oil field pilot tests. The effects of CO2 injection on crude oil are complex, mainly including dissolution, expansion, viscosity reduction, diffusion and mass transfer. The effects of different mechanisms on the level of miscibility are also different due to the different compositions of crude oil. In addition, the mixing of impurity gases, water shielding, and pore scale effects aggravate the difference of various mechanisms. This paper reviews the current research into the CO2 flooding method. Besides, combined with the actual demand of oil and gas exploration and development, this paper summarizes the status and existing problems of CO2 flooding during its promotion and application. At present, the research and field application of CO2 flooding often pays too much attention to the minimum miscibility pressure, which makes the realization of achieving a miscible supplement the determinant of implementing CO2 flooding in oil fields. Many reservoirs with favorable conditions are rejected simply because they cannot meet the minimum miscibility pressure. Therefore, focusing on the near-miscible CO2 flooding technique, which is easier to realize in practical applications, three key factors limiting the effective development are proposed. The application and development of CO2 near-miscible flooding in the future are discussed. Both experiments and field tests have fully verified the advantages of this technique in improving oilfield development. Lower injection pressure and operation cost obviously eased the limitation of miscible flooding in the characteristics of reservoir, quality of oil and gas sources of China. However, a definition of near-miscible flooding is still not agreed, the determination of the near-miscible pressure interval is still a blank, and the typical phase behavior and mechanisms of displacement are not yet clear. In the proc

关 键 词：近混相压力区间 产出气回注 水盾阻隔 孔隙尺寸效应 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程]