油气地质与采收率2026，Vol.33Issue(1)：207-218,12.DOI:10.13673/j.pgre.202509039
基于CO2驱替前缘扩展的低渗透油藏混相带时空演化机理
Spatiotemporal evolution mechanism of miscible zone in low-permeability reservoirs based on CO2 flooding front propagation
摘要
Abstract
Under the"carbon peaking and carbon neutrality"strategy,CO2 flooding is regarded as a preferred approach to simultaneously enhance oil recovery and achieve geological storage in low-permeability reservoirs,yet its field performance often falls short of expectations.To clarify the spatiotemporal evolution mechanism of the oil-gas miscible zone during CO2 flooding,physical simulation experiments of long-core CO2 flooding were conducted and complemented with multi-scale numerical simulations.The study systematically characterized the differential propagation of miscible pressure fronts,phase fronts,and compositional fronts,as well as the dynamic evolution of the miscible zone during CO2 flooding.Results show that,influenced by hydrocarbon component migration characteristics and multi-contact interactions,the miscible pressure front advances fastest,while the phase front lags behind the compositional front,leading to pronounced temporal and spatial variability in miscible zone distribution.Enhancing miscibility helps suppress the advance of the compositional front and delays the development of CO2 breakthrough channels.Moreover,injection rate and volume exert significant regulatory effects on front propagation:when the injected CO₂ volume increases from 0.2 PV to 0.6 PV,the phase front extension reaches 68％,effectively broadening the miscible zone.However,excessive injection rates accelerate compositional front migration and aggravate gas channeling risks.Reservoir heterogeneity further complicates miscible zone distribution;when matrix permeability rises from 1.0×10-3 μm2 to 15.0×10-3 μm2,the CO2 phase sweep coefficient increases by 57.9％,whereas higher fracture permeability facilitates preferential compositional front migration through high-permeability pathways,resulting in uneven miscible zone distribution.关键词
低渗透油藏/CO2驱替/混相带/前缘/非完全混相Key words
low-permeability reservoir/CO2 flooding/miscible zone/displacement front/non-complete miscibility分类
能源科技引用本文复制引用
刘希良,陈浩,李阳,张来斌,曾宏波..基于CO2驱替前缘扩展的低渗透油藏混相带时空演化机理[J].油气地质与采收率,2026,33(1):207-218,12.基金项目
新型油气勘探开发国家科技重大专项"CO2驱大幅度提高采收率与长期封存技术"(2024ZD1406600),中国博士后科学基金第78批面上基金项目"海上深层油藏非纯CO2驱混相机理与混相带演化规律研究"(2025M782975),中国石油大学(北京)科研基金项目"海上低渗透油藏注CO2过程中前缘运移规律研究"(2462025XKBH026). （2024ZD1406600）
