页岩凝析气受限空间相态及开发特征研究  

Phase behavior and development characteristics of shale condensate gas in confined space

作　　者：汤勇[1] 陈焜 胡小虎 方思冬[2,3] 刘华 TANG Yong;CHEN Kun;HU Xiaohu;FANG Sidong;LIU Hua(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China;State Key Laboratory of Shale Oil and Gas Enrichment Mechanism and Effective Development,Beijing 100083,China;Sinopec Petroleum Exploration and Development Research Institute,Beijing 100083,China)

机构地区：[1]西南石油大学油气藏地质及开发工程全国重点实验室,四川成都610500 [2]页岩油气富集机理与有效开发国家重点实验室,北京100083 [3]中国石化石油勘探开发研究院,北京100083

出　　处：《油气藏评价与开发》2024年第3期343-351,共9页Petroleum Reservoir Evaluation and Development

基　　金：国家自然科学基金面上项目“超低渗透油藏CO_(2)强化采油过程中多孔介质相态及微观渗流机理研究”(51974268)。

摘　　要：涪页10井的钻探获取了东岳庙段典型陆相页岩相关特征参数,其页岩储层介孔和大孔发育,非均质性较强,主要孔隙分布在10nm左右。纳米孔中受限流体的临界参数偏移使得受限空间下凝析气的流体性质与常规室内实验测试结果存在差异。为更合理地开采页岩凝析气,结合室内相态实验、受限流体临界参数偏移计算和数值模拟,开展页岩凝析气相态特征分析和开采特征研究,明确凝析气的相态变化规律和开采特征。考虑临界参数偏移的凝析气相态特征计算表明:随着孔隙半径减小,体系组分的临界温度、临界压力降低,相图向左下收缩,露点压力降低,气相黏度降低,偏差因子增加,反凝析液饱和度逐渐降低。通过机理模型分析了临界参数偏移对衰竭开采效果的影响,结果表明:随着孔隙半径减小,天然气采收率基本不变,凝析油采收率逐渐增加,孔隙半径减小至10nm,凝析油采收率增加9.93%。研究结果对页岩凝析气藏开发具有指导意义。The exploration of Well-Fuye-10 in the Dongyuemiao section has provided valuable characteristic parameters of typical continental shale,revealing a reservoir with well-developed mesopores and macropores and significant heterogeneity.The predominant pore sizes are around 10 nm.Notably,deviations in the critical parameters of the confined fluids alter the condensate gas properties within these nanopores,differentiating them from conventional laboratory results.This study combines indoor phase state experiments,critical parameter migration calculations,and numerical simulations of confined fluids to analyze the phase state characteristics and extraction properties of shale condensate gas.The findings elucidate the phase state transformation and extraction dynamics of the condensate gas.Adjustments in the calculations for condensate gas phase characteristics to account for critical parameter offsets indicate that as pore radius decreases,there is a corresponding reduction in critical temperature and pressure of the system components.This results in a contraction of the phase diagram towards the lower left,a decrease in dew point pressure,reduced gas phase viscosity,an increase in deviation factor,and a gradual decrease in retrograde condensate saturation.Additionally,a mechanism model was employed to assess the impact of critical parameter shifts on depletion extraction effectiveness.Results demonstrate that while the recovery rate of natural gas remains relatively unchanged,the recovery rate of condensate oil shows a significant increase,rising by 9.93% as the pore radius decreases to 10 nm.These insights offer pivotal guidance for the development of shale condensate gas reservoirs,particularly in managing the unique phase behavior and optimizing recovery strategies.

关 键 词：页岩凝析气 陆相页岩 受限空间 相态变化 临界参数偏移 开发特征 

分 类 号：TE372[石油与天然气工程—油气田开发工程]