为了明确非常规储层注CO2开发时石英壁面的润湿性动态变化,采用分子动力学模拟方法,计算不同CO2压力条件下水滴润湿羟基石英和甲基石英壁面的过程。研究表明:羟基石英初始强亲水,甲基石英初始弱亲CO2,随着CO2压力增大,亲水性降低,且羟基石英润湿性变化较小,甲基石英润湿性变化较大;随着CO2压力增大,CO2分子和水分子共同吸附在甲基石英壁面,形成不连续的CO2吸附膜,降低非键相互作用,导致亲水性降低,直至CO2压力达到44.96 MPa,接触角达到180.00°;随着CO2压力增大,接触线区域水分子数量降低,运动空间被压缩,壁面对水分子的束缚作用降低,导致水分子的跳跃频率降低,跳跃距离增大;与甲基石英相比,羟基石英的亲水性更强,水分子的跳跃频率更大,跳跃距离更小。该研究揭示了不同CO2压力下羟基石英和甲基石英的接触角动态变化机制,建立了接触角与渗流速度、CO2压力的关系,提出更加精确的毛管力描述。研究成果不仅为纳米限域流体流动提供了新的理论支持,还为储层评估、产能预测及开发策略制订提供了更为可靠的依据。
To clarify the dynamic wettability changes during CO2 injection in unconventional reservoirs,molecular dynamics simulations were performed of water droplets wetting hydroxylated quartz and methylated quartz surfaces at various CO2 pressures.The study shows that hydroxylated quartz is initially strongly hydrophilic,while methylated quartz is initially weakly CO2-affine;as CO2 pressure increased,the water wettability of both decreased,with smaller changes for hydroxylated quartz and larger changes for methylated quartz.With higher CO2 pressure,CO2 and water molecules co-adsorbed on the methylated quartz surface,forming a discontinuous CO2 adsorption film that reduced non-bonded interactions and led to lower hydrophilicity until at 44.96 MPa the water contact angle reaches to 180.00°.As CO2 pressure increases,the number of water molecules in the contact line region decreased and their motion space is compressed,reducing water molecular jump frequency and increasing jump distance.Compared with methylated quartz,hydroxylated quartz remains more hydrophilic with higher water molecule jump frequency and shorter jump distance.This study revealed the dynamic mechanisms of contact angle change for hydroxylated vs. methylated quartz under varying CO2 pressures,established relationships between contact angle,relative permeability and CO2 pressure and then a more accurate description of capillary pressure is proposed.These results provide new theoretical support for nanoscale fluid flow and a more reliable basis for reservoir evaluation,productivity prediction, and development strategy.
[1] WANG Z,YU C,ZHAO J, et al.Molecular dynamics simulation for quantitative characterization of wettability transition on silica surface[J].Journal of Materials Research and Technology, 2022, 19: 4371-4380.
[2] 任红梅,孟庆春,范忠钰,等.羟基化及硅烷化二氧化硅表面润湿行为的分子模拟[J].中国石油大学学报(自然科学版),2014,38(5):172-177.
REN Hongmei,MENG Qingchun,FAN Zhongyu,et al.Molecular simulation of wetting behavior on hydroxylation and silanization SiO2 surface[J].Journal of China University of Petroleum(Edition of Natural Science),2014,38(5):172-177.
[3] CARLOS B,DONATAS S,HIROKI K, et al.Water on hydroxylated silica surfaces:work of adhesion,interfacial entropy,and droplet wetting[J].The Journal of Chemical Physics,2021,155(6):064703.
[4] DENG Y,WU Q,LI Z, et al.Crystal face dependent wettability of α-quartz: elucidation by time-of-flight secondary ion mass spectrometry techniques combined with molecular dynamics[J].Journal of Colloid and Interface Science, 2022, 607:1699-1708.
[5] DENG Y,LI Z,RAO S,et al. Mechanism for the effects of surface chemical composition and crystal face on the wettability of α-quartz surface[J].Applied Surface Science,2023,633:157559.
[6] CHIQUET P,BROSETA D,THIBEAU S.Wettability alteration of caprock minerals by carbon dioxide[J].Geofluids, 2007, 7(2): 112-122.
[7] YU T, LI Q,LI X,et al.Synergistic effects of CO2 density and salinity on the wetting behavior of formation water on sandstone surfaces:molecular dynamics simulation[J].Journal of Natural Gas Science and Engineering, 2022, 105: 104714.
[8] IGLAUER S,MATHEW S M,BRESME F.Molecular dynamics computations of brine-CO2 interfacial tensions and brine-CO2-quartz contact angles and their effects on structural and residual trapping mechanisms in carbon geo-sequestration[J].Journal of Colloid and Interface Science, 2012, 386(1): 405-414.
[9] 杨杰.SC-CO2对地层水在岩石表面润湿行为影响的分子模拟[D].青岛:中国石油大学(华东),2014.
YANG Jie.Molecular simulation of the effect of SC-CO2 on formation water wetting behavior on rock surface[D].Qingdao:China University of Petroleum (East China),2014.
[10] BLAKE D T,BATTS N G.The temperature-dependence of the dynamic contact angle[J].Journal of Colloid and Interface Science, 2019, 553: 108-116.
[11] 施砍园,陈君青,庞雄奇,等.储层矿物润湿性的测量方法综述[J].特种油气藏,2024,31(2):1-9.
SHI Kanyuan,CHEN Junqing,PANG Xiongqi,et al.A review of methods for measuring the wettability of reservoir minerals[J].Special Oil & Gas Reservoirs,2024,31(2):1-9.
[12] CYGAN T R,LIANG J,KALINICHEV G A. Molecular models of hydroxide, oxyhydroxide, and clay phases and the development of a general force field[J].The Journal of Physical Chemistry B, 2004, 108(4):1255-1266.
[13] WILLIAM L J,DAVID S M,JULIAN T R. Development and testing of the OPLS all-atom force field on conformational energetics and properties of organic liquids[J].Journal of the American Chemical Society,1996,118(45): 11225-11236.
[14] ABRAMOV A,IGLAUER S.Application of the CLAYFF and the DREIDING force fields for modeling of alkylated quartz surfaces[J].Langmuir, 2019, 35(17): 5746-5752.
[15] YAN H,YUAN S.Molecular dynamics simulation of the oil detachment process within silica nanopores[J].The Journal of Physical Chemistry C, 2016, 120(5): 2667-2674.
[16] CYGAN T R,ROMANOV N V,MYSHAKIN M E. Molecular simulation of carbon dioxide capture by montmorillonite using an accurate and flexible force field[J].The Journal of Physical Chemistry C,2012,116(24):13079-13091.
[17] IGLAUER S,PENTLAND C H,BUSCH A. CO2 wettability of seal and reservoir rocks and the implications for carbon geo-sequestration[J].Water Resources Research, 2015, 51(1): 729-774.
[18] ZHOU J,ZHANG J,YANG J, et al.Mechanisms for kerogen wettability transition from water-wet to CO2-wet:implications for CO2 sequestration[J].Chemical Engineering Journal, 2021, 428: 132020.
[19] 郑文秀,温伯尧,白博峰.油-水-固三相接触线移动的温度影响机制[J].中国科学:物理学 力学 天文学,2024,54(2):224706.
ZHENG Wenxiu,WEN Boyao,BAI Bofeng.Mechanism underlying influence of temperature on oil-water-solid contact-line movement[J].Scientia Sinica(Physica,Mechanica & Astronomica), 2024, 54(2):224706.
[20] LI H, SEDEV R, RALSTON J.Dynamic wetting of a fluoropolymer surface by ionic liquids[J].Physical Chemistry Chemical Physics, 2011, 13(9): 3952-3959.
[21] GOOSSENS S,SEVENO D,RIOBOO R, et al.Can we predict the spreading of a two-liquid system from the spreading of the corresponding liquid-air systems?[J].Langmuir, 2011, 27(16): 9866-9872.
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