N_2对CO_2最小混相压力的影响  

Effect of N_2 on minimum miscible pressure of CO_2 flooding

作　　者：李康宁[1] 宫厚健[1] 王冲[2] 李润虎[3] 龙菲菲 董明哲[1] 

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]中国石油长庆油田公司勘探开发研究院,陕西西安710018 [3]中国石油长庆油田分公司第一采油厂,陕西延安716000

出　　处：《断块油气田》2016年第6期763-767,共5页Fault-Block Oil & Gas Field

基　　金：国家重点基础研究发展计划(973计划)项目"陆上页岩油储集性能与流动机理"(2014CB239103);国家自然科学基金项目"油气水三相微观-连续介质三维流动模拟研究"(51274225);"缝洞型介质等效连续模型油水两相流动模拟理论研究"(51204198);"超临界CO2微乳液体系的构筑及其驱油机理研究"(51204197);教育部高等学校博士学科点专项科研基金项目"注溶剂提高稠油采收率的微观-连续介质模拟研究"(20110133110007)

摘　　要：向复杂断块油藏注入CO2,既可通过混相驱提高原油采收率,又可节约成本,封存大量温室气体,减缓温室效应。由于断层封闭性及CO2混相均受压力影响,又因注入CO2中常混有N2,因此,文中深入研究N2对CO2-原油最小混相压力的影响。通过Win Prop模块模拟计算了原油分子摩尔质量为170~360 g/mol,油藏温度为310~360 K,N2摩尔分数至10%,约2 000种情况下的混相压力,得到N2影响的CO2混相压力与纯CO2混相压力比值（Fimp）表达式。结果显示,Fimp与注入气体中N2的摩尔分数成正比,不同组成的原油对Fimp没有影响,得到了N2存在情况下CO2-原油最小混相压力的表达式。与CO2混相实验结果及已发表公式计算结果对比发现,该表达式能准确计算N2存在情况下CO2-原油混相压力,为CO2混相驱提高原油采收率及筛选断块油气藏实施混相驱提供理论依据。Injection of CO2 into complex fault block reservoirs can improve oil recovery, offset the cost, store greenhouse gas and mitigate the greenhouse effect. Since the sealing properties of fault block and CO2 miscible properties are sensitive to pressure, so the selection of the potential reservoir is very critical. Normally CO2 is contaminated by N2, this paper studies the effect of N2 on the CO2-oil minimum miscible pressure. Through Win Prop simulation, about 2 000 sets of the ratio of N2-affected CO2 minimum miscible pressure to pure CO2 minimum miscible pressure（Fimp） were obtained, which have considered the oil molecular weight range in 170-360 g/mol, reservoir temperature in 310-360 K, and the concentration of N2 up to 10%. The results show that the Fimpincreases with the mole fraction of N2. The oil composition has no influence on Fimp. This paper creates a correlation for predicting Fimpwhen N2 exists. Compared with published experimental data and CO2-oil MMP correlations in literature, this new correlation can calculate the N2 contaminated CO2-oil MMP more accurately, which provides theoretical basis for improving oil recovery and screening suitable fault reservoirs for miscible flooding.

关 键 词：CO2埋存 温室气体 断层封闭性 最小混相压力 N2 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程]