余洋阳,侯大力,顾康福,黄思婧,韩鑫
YU Yangyang,HOU Dali,GU Kangfu,HUANG Sijing,HAN Xin

• 1:成都理工大学能源学院
• 2:油气藏地质及开发工程国家重点实验室
• 3:西南石油大学地球科学与技术学院

摘要(Abstract)：

凝析气藏开采中后期，地层压力下降，会出现油气两相共存，井周反凝析问题突出，此时注CO_2开发是主要增产措施之一，注入的CO_2会与凝析油、气发生分子扩散。为了研究CO_2在凝析气中的扩散规律，开展了多孔介质中CO_2在衰竭至不同压力下的凝析气中扩散系数的实验测定；应用Materials Studio软件，构建了与实验条件对应的CO_2在凝析气中扩散的分子模型，并验证了分子模型的可靠性。实验和模拟结果表明：地层温度下，压力为10.00～53.85 MPa时，随着压力的升高，CO_2的扩散系数开始快速下降，随后下降趋势平缓；地层压力下，温度为115～160℃时，随着温度的升高，CO_2的扩散系数不断增大，与温度大致呈线性关系，表明高温可增强CO_2在凝析气中扩散的能力。研究成果为注CO_2提高凝析气藏采收率提供了理论基础。
In the middle and late stages of exploitation of condensate gas reservoirs, formation pressure drops, and 2 phases of oil and gas coexist, and the problem of trograde condensate around well is serious. At this time, CO_2 injection development is one of the main solutions to increase production, with injected CO_2 having molecular diffusion with condensate oil and gas. It is of great significance to study diffusion capability of CO_2 in condensate gas for exploitation of condensate gas reservoirs. Firstly, diffusion coefficient of CO_2 in porous media in condensate gas from depletion to different pressure is measured experimentally. Secondly, using Materials Studio software, a molecular model of CO_2 diffusion in condensate gas corresponding to experimental conditions is built, and the reliability of the molecular model is verified. Experimental and simulation results show that, at formation temperature, when the pressure is in the range of 10.00～53.85 MPa, with the increase of pressure, CO_2 diffusion coefficient decreases rapidly at first, and then downward trend tends to be gentle. At formation pressure, when the temperature is in the range of 115～160 ℃, CO_2 diffusion coefficient increases continuously with temperature rise, being roughly linear with temperature, indicating the capability of high temperature to promote CO_2 diffusion in condensate gas. The research results provide theoretical basis for CO_2 injection to enhance recovery of condensate gas reservoirs.

关键词(KeyWords)： 多孔介质;CO_2;凝析气;扩散系数;分子模拟
porous media;CO_2;condensate gas;diffusion coefficient;molecular simulation

Abstract:

Keywords:

基金项目(Foundation): 中国博士后基金项目“高温高压下CO2-近临界原油-地层水三相相平衡表征模型”（2017M612995）;; 四川省科技厅应用基础研究项目“储层条件超临界CO2压裂液-页岩气-页岩多相相互作用复杂机理研究”（2021YJ0352）;; 油气藏地质及开发工程国家重点实验室自由探索项目“储层条件超临界CO2-地层水-页岩气-页岩多相相互作用复杂机理研究”（CZ201910）

作者(Author): 余洋阳,侯大力,顾康福,黄思婧,韩鑫
YU Yangyang,HOU Dali,GU Kangfu,HUANG Sijing,HAN Xin

DOI: 10.19597/j.issn.1000-3754.202206026

参考文献(References)：

• [1]张宇飞，赵法军，徐天晓，等.凝析气藏注CO2解除反凝析伤害评价[J].当代化工，2021,50(1):217-220,224.ZHANG Yufei,ZHAO Fajun,XU Tianxiao,et al. Evaluation of removing retrograde condensate damage by injecting CO2 into condensate gas reservoir[J]. Contemporary Chemical Industry,2021,50(1):217-220,224.
• [2]常宝华，李世银，曹雯，等.缝洞型碳酸盐岩油气藏关键开发指标预测方法及应用[J].特种油气藏，2021,28(2):72-77.CHANG Baohua,LI Shiyin,CAO Wen,et al. Prediction method of key development indicators of fracture-cavity carbonate reservoirs and its application[J]. Special Oil&Gas Reservoirs,2021,28(2):72-77.
• [3]舒志国，周林，李雄，等.四川盆地东部复兴地区侏罗系自流井组东岳庙段陆相页岩凝析气藏地质特征及勘探开发前景[J].石油与天然气地质，2021,42(1):212-223.SHU Zhiguo,ZHOU Lin,LI Xiong,et al. Geological characteristics of gas condensate reservoirs and their exploration and development prospect in the Jurassic continental shale of the Dongyuemiao Member of Ziliujing Formation,Fuxing area,eastern Sichuan Basin[J]. Oil&Gas Geology, 2021, 42(1):212-223.
• [4]李鸿儒，谭忠健，胡云，等.渤中凹陷西南环M构造太古界潜山油气藏流体类型随钻识别方法[J].油气地质与采收率，2021,28(5):22-31.LI Hongru, TAN Zhongjian, HU Yun, et al. Reservoir fluid type identification while drilling for Archaeozoic buried hill reservoir of M structure at southwest margin of Bozhong Sag, Bohai Sea, East China[J]. Petroleum Geology and Recovery Efficiency,2021,28(5):22-31.
• [5]齐桂雪，李中超，刘平，等.凝析气藏气驱二维填砂物理模型实验研究[J].断块油气田，2022,29(2):164-170.QI Guixue, LI Zhongchao, LIU Ping, et al. An experimental study of two-dimensional sand filling physical model for gas flooding in condensate gas reservoir[J]. Fault-Block Oil&Gas Field,2022,29(2):164-170.
• [6]史林祥.凝析气藏相态特征及其开发规律研究[D].北京：中国地质大学，2019.SHI Linxiang. Study on phase characteristics and development law of condensate gas reservoir[D]. Beijing:China University of Geosciences,2019.
• [7]陈雷，罗辑，饶华文，等.凝析气藏开发中后期注气提高采收率[J].新疆石油地质，2019,40(1):98-102.CHEN Lei,LUO Ji,RAO Huawen,et al. Gas injection EOR at mid-late development stage in condensate gas reservoirs[J].Xinjiang Petroleum Geology,2019,40(1):98-102.
• [8] DATCHAWAN U, KOOROSH A, JOSE C. Experimental studies of CO2 and CH4 diffusion coefficient in bulk oil and porous media[J].Energy Procedia,2011,4:2170-2177.
• [9] ZHONG Y,SHE J P,ZHANG H,et al. Experimental and numerical analyses of apparent gas diffusion coefficient in gas shales[J]. Fuel,2019,258:116-123.
• [10]银占华，赵希春，刘振东.天然气扩散系数测试装置的研制[J].石油仪器，2014,28(3):19-21,16.YIN Zhanhua,ZHAO Xichun,LIU Zhendong,et al. Development of natural gas diffusion coefficient testing device[J]. Petroleum Tubular Goods&Instruments,2014,28(3):19-21,16.
• [11]郭平，涂汉敏，汪周华，等.多组分气?气扩散系数的计算[J].天然气工业，2015,35(8):39-43.GUO Ping,TU Hanmin,WANG Zhouhua,et al. Calculation of multi-component gas-gas diffusion coefficient[J]. Natural Gas Industry,2015,35(8):39-43.
• [12]史云清，贾英，潘伟义，等.低渗致密气藏注超临界CO2驱替机理[J].石油与天然气地质，2017,38(3):610-616.SHI Yunqing,JIA Ying,PAN Weiyi,et al. Mechanism of supercritical CO2 flooding in low-permeability tight gas reservoirs[J]. Oil&Gas Geology,2017,38(3):610-616.
• [13]杨兆中，韩金轩，张健，等.泡沫压裂液添加剂对煤层甲烷扩散影响的分子模拟[J].煤田地质与勘探，2019,47(5):94-103.YANG Zhaozhong,HAN Jinxuan,ZHANG Jian,et al. Molecular simulation of the influence of foam fracturing fluid additives on coalbed methane diffusion[J]. Coal Geology&Exploration,2019,47(5):94-103.
• [14] LIU Jing,LI S K,WANG Yang. Molecular dynamics simulation of diffusion behavior of CH4,CO2,and N2 in mid-rank coal vitrinite[J]. Energies,2019,12(19):1-21.
• [15] ZHAO X,JIN H,CHEN Y,et al. Numerical study of H2,CH4,CO,O2 and CO2 diffusion in water near the critical point with molecular dynamics simulation[J]. Computers&Mathematics with Applications,2021,81:759-771.
• [16]郭淑婷，黄维秋，钟璟，等.有机蒸气?空气扩散系数的分子动力学模拟[J].科学技术与工程，2017, 17(11):282-287.GUO Shuting,HUANG Weiqiu,ZHONG Jing,et al. Molecular dynamics simulation of organic vapor-air diffusion coefficient[J]. Science Technology and Engineering, 2017, 17(11):282-287.
• [17]林海飞，刘静波，严敏，等.CO2/CH4在煤储层中扩散规律的分子动力学模拟[J].中国安全生产科学技术，2017,13(1):84-89.LIN Haifei,LIU Jingbo,YAN Min,et al. Molecular dynamics simulation on diffusion rules of CO2/CH4 in coal reservoir[J].Journal of Safety Science and Technology, 2017, 13(1):84-89.
• [18]任俊豪，任晓海，宋海强，等.基于分子模拟的纳米孔内甲烷吸附与扩散特征[J].石油学报，2020, 41(11):1366-1375.REN Junhao,REN Xiaohai,SONG Haiqiang,et al. Adsorption and diffusion characteristics of methane in nanopores based on molecular simulation[J]. Acta Petrolei Sinica, 2020, 41(11):1366-1375.
• [19]中华人民共和国石油天然气行业标准.岩石中烃类气体扩散系数测定：SY/T 6129―1995[S].北京：中国石油天然气总公司，1995.Petroleum and natural gas industry standard of the People,s Republic of China. Determination of hydrocarbon gas diffusivity in rocks:SY/T 6129―1995[S]. Beijing:China National Petroleum Corporation,1995.
• [20] COLLELL J, UNGERER P, GALLIERO G, et al. Molecular simulation of bulk organic matter in TypeⅡshales in the middle of the oil formation window[J].Energy&Fuels,2014,28(12):7457-7466.
• [21] THEODOROU D N,SUTER U W. Detailed molecular structure of a vinyl polymer glass[J]. Macromolecules,1985,18(7):1467-1478.
• [22] FRENKEL D, SMIT B. Understanding molecular simulations:From algorithms to applications[M]. San Diego:Academic Press,1996.
• [23]苑世领，张恒，张冬菊，等.分子模拟：理论与实验[M].北京：化学工业出版社，2016.YUAN Shiling,ZHANG Heng,ZHANG Dongju,et al. Molecular Simulation:Theory and Experiment[M]. Beijing:Chemical Industry Press,2016.
• [24]叶正扬，樊小哲，龙军，等.沥青质分子结构与沥青材料性能关系的分子模拟[J].石油学报（石油加工），2022,38(2):367-379.YE Zhengyang,FAN Xiaozhe,LONG Jun,et al. Molecular dynamics study on the relationship between asphaltene molecular structures and asphalt material propertie[J]. Acta Petrolei Sinica(Petroleum Processing Section),2022,38(2):367-379.
• [25]李美俊，刘晓强，韩秋雅，等.分子模拟在油气地球化学中的应用研究进展[J].石油与天然气地质，2021,42(4):919-930.LI Meijun,LIU Xiaoqiang,HAN Qiuya,et al. Progress of molecular simulation application research in petroleum geochemistry[J].Oil&Gas Geology,2021,42(4):919-930.
• [26]唐巨鹏，孙胜杰，包思远.高岭石甲烷吸附规律的分子模拟研究[J].油气地质与采收率，2019,26(4):43-49.TANG Jupeng, SUN Shengjie, BAO Siyuan. Molecular simulation of methane adsorption on Kaolinite[J]. Petroleum Geology and Recovery Efficiency,2019,26(4):43-49.
• [27]曾克成，姜培学，张富珍，等.方解石纳米孔隙内二氧化碳毛细凝聚的分子模拟[J].工程热物理学报，2021,42(1):203-209.ZENG Kecheng, JIANG Peixue, ZHANG Fuzhen, et al.Molecular simulation of CO2 capillary condensation in nanopores[J]. Journal of Engineering Thermophysics, 2021, 42(1):203-209.