摘要
为了探究CO_2在低渗透油藏中与原油的混相条件及在近混相条件下的驱油效果,采用室内物理模拟方法,通过均质、非均质长方体岩心实验,在评价影响CO_2驱油效果的渗透率、岩心长度、渗透率级差和压力因素的基础上,借助采收率与各影响因素参数指标,分析非混相、近混相和混相不同阶段的曲线特征,建立了近混相驱区域的确定方法。采用该岩心实验方法,在模拟油藏条件下,CO_2与原油的最小混相压力为18.5 MPa左右,比传统细管实验确定的17.8 MPa高出0.7 MPa,同时根据驱油曲线特征,划分了CO_2非混相、近混相和混相区域,并根据驱油效率确定出近混相驱的压力区域为16.5数18.5 MPa。建立的最小混相压力岩心测定方法和近混相驱区域划定的方法,为进一步深化CO_2近混相驱油机理的认识及YC油田CO_2矿场驱油方案的设计提供了参考。
Whether CO2 flooding can be mixed with crude oil under reservoir conditions directly affects the oil displacement efficiency, therefore CO2 miscible and near-miscible flooding in low permeability reservoirs was studied. By conducting CO2 flooding experiment in both homogeneous and heterogeneous rectangular cores, the oil recovery results were acquired through the various series of experiments considering permeability ,migration distance, permeability differential as welt as the flooding pressure under the simulated reservoir conditions. Therefore, the classification of the immiscible, near-miscible and miscible CO2 flooding in low permeability reservoir was determined by the gas flooding results, and the near-miscible area was also defined. The minimum miscible pressure （MMP）of C02 with crude oil was 18.5 MPa in this study, which was 0.7 MPa higher than that determined by slim tube experiment （ 17.8 MPa）, a conventional method to determine the carbon dioxide MMP. Based on the displacement curve, the CO2 flooding process was divided into three stages, immiscible, near-miscible and miscible region. The near-miscible pressure of CO： displacement in YC oil ranges from 16.5 MPa to 18.5 MPa. The MMP measuring of CO2 flooding was determined by core flooding method and the near-miscible flooding region was defined, which offered reference to the further understanding of mechanism in CO2 near-miscible displacement and scheme design of CO2 flooding in YC oilfield.
作者
赵凤兰
张蒙
侯吉瑞
侯利斌
郝宏达
王鹏
鲁国用
ZHAO Fenglan;ZHANG Meng;HOU Jirui;HOU Libin;HAO Hongda;WANG Peng;LU Guoyong(Research Institute of Enhanced Oil Recovery,China University of Petroleum（Beifing）,Beijing 102249,P R of China;MOE Key Laboratory of Petroleum Engineering,China University of Petroleum（Beijing）,Beijing 102249,P R of China;Key Laboratory of Greenhouse Gas Sequestration and Oil Exploitation,Beijing 102249,P R of China）3)
出处
《油田化学》
CAS
CSCD
北大核心
2018年第2期273-277,共5页
Oilfield Chemistry
基金
十三五国家科技重大专项课题
"低渗-致密油藏高效提高采收率技术"(项目编号2017ZX05009-004)
"海外重点油气开发钻采关键技术"(项目编号2017ZX05032-004)
关键词
低渗透油藏
CO2近混相驱
混相压力
岩心驱替实验
low permeability reservoir
carbon dioxide near miscible flooding
miscible pressure
core displacement experiment
