特低渗透砂岩油藏CO_(2)驱原油动用特征及埋存机理  

Oil production characteristics and CO2 storage mechanisms of CO_(2) flooding in ultra-low permeability sandstone oil reservoirs

作　　者：刘希良 陈浩[1,2] 李阳[4] 祝仰文 廖海婴 赵清民[5] 周显民 曾宏波 LIU Xiliang;CHEN Hao;LI Yang;ZHU Yangwen;LIAO Haiying;ZHAO Qingmin;ZHOU Xianmin;ZENG Hongbo(Hainan Institute of China University of Petroleum(Beijing),Beijing 102249,China;State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;Donadeo Innovation Centre for Engineering,University of Alberta,Edmonton T6G1H9 Canada;China Petroleum&Chemical Corporation,Beijing 100728,China;Sinopec Petroleum Exploration and Production Research Institute,Beijing 102206,China;Acrocean Sci&Tech Development LLC,Houston 77433,United States)

机构地区：[1]中国石油大学(北京)海南研究院,北京102249 [2]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [3]阿尔伯塔大学多纳多工程创新中心,埃德蒙顿T6G1H9 [4]中国石油化工股份有限公司,北京100728 [5]中国石化石油勘探开发研究院,北京102206 [6]美国海洋科技发展有限责任公司,美国休斯顿77433

出　　处：《石油勘探与开发》2025年第1期174-184,共11页Petroleum Exploration and Development

基　　金：国家自然科学基金面上项目“致密砂岩油藏注CO_(2)微纳米孔喉内流体的空间再分布及输运行为研究”(52274053);北京市自然科学基金面上项目“面向双碳目标的页岩油藏注CO_(2)微观增油机制研究”(3232028)。

摘　　要：以江苏油田特低渗透油藏L区块为例,基于CO_(2)-原油体系长细管驱替实验、注入能力测试和高温高压在线核磁共振驱替等实验,揭示特低渗透油藏CO_(2)驱油气传质规律和原油动用机理,明确CO_(2)驱替过程中CO_(2)埋存孔隙范围和混相程度对原油动用特征及CO_(2)埋存特征的影响规律。结果表明:CO_(2)驱油过程划分为CO_(2)顶替阶段、CO_(2)突破阶段和CO_(2)抽提阶段,原油膨胀和黏度降低是CO_(2)驱顶替阶段提高采收率的主要机制,CO_(2)突破后通过抽提、萃取原油中轻质组分进一步提高采收率;CO_(2)驱过程中,大孔内原油对提高采收率的贡献率达46%以上,中孔内原油为增油的接替储备,CO_(2)突破后小部分抽提的原油被CO_(2)裹挟进入纳米级孔隙成为较难动用的剩余油;随着混相程度的提高,CO_(2)前缘推进更稳定,波及范围更广,CO_(2)埋存范围和埋存量更大。CO_(2)完全埋存阶段对整体埋存量贡献最大,CO_(2)逸散阶段埋存机理为部分原油在初始赋存孔隙范围的原位埋存和CO_(2)裹挟原油进入更小孔隙从而增大埋存量,CO_(2)泄漏阶段随着原油产出CO_(2)大量泄漏,埋存率急剧降低。Using the ultra-low permeability reservoirs in the L block of the Jiangsu oilfield as an example,a series of experiments,including slim tube displacement experiments of CO_(2)-oil system,injection capacity experiments,and high-temperature,high-pressure online nuclear magnetic resonance displacement experiments,are conducted to reveal the oil/gas mass transfer pattern and oil production mechanisms during CO_(2) flooding in ultra-low permeability reservoirs.The impacts of CO_(2) storage pore range and miscibility on oil production and CO_(2) storage characteristics during CO_(2) flooding are clarified.The CO_(2) flooding process is divided into three stages:oil displacement stage by CO_(2),CO_(2) breakthrough stage,CO_(2) extraction stage.Crude oil expansion and viscosity reduction are the main mechanisms for improving recovery in the CO_(2) displacement stage.After CO_(2) breakthrough,the extraction of light components from the crude oil further enhances oil recovery.During CO_(2) flooding,the contribution of crude oil in large pores to the enhanced recovery exceeds 46%,while crude oil in medium pores serves as a reserve for incremental recovery.After CO_(2) breakthrough,a small portion of the crude oil is extracted and carried into nano-scale pores by CO_(2),becoming residual oil that is hard to recover.As the miscibility increases,the CO_(2) front moves more stably and sweeps a larger area,leading to increased CO_(2) storage range and volume.The CO_(2) full-storage stage contributes the most to the overall CO_(2) storage volume.In the CO_(2) escape stage,the storage mechanism involves partial in-situ storage of crude oil within the initial pore range and the CO_(2) carrying crude oil into smaller pores to increase the volume of stored CO_(2).In the CO_(2) leakage stage,as crude oil is produced,a significant amount of CO_(2) leaks out,causing a sharp decline in the storage efficiency.

关 键 词：特低渗透油藏 CO_(2)驱替 混相程度 原油动用特征 埋存特征 

分 类 号：TE344[石油与天然气工程—油气田开发工程]