小分子胺对蒙脱石水化抑制作用的分子动力学模拟  

Molecular Dynamics Simulation of Inhibition of Small Molecule Amines on Hydration of Montmorillonite

作　　者：马超[1,2,3] 王诚 刘鑫 高胜天 黄晓依 MA Chao;WANG Cheng;LIU Xin;GAO Shengtian;HUANG Xiaoyi(College of Petroleum Engineering,Yangtze University,Wuhan,Hubei 430100,China;Key Laboratory of Hubei Province for Oil and GasDrilling and Production Engineering,(Yangtze University),Wuhan,Hubei 430100,China;National Engineering Research Center for Oil&Gas Drilling and Completion Technology,Wuhan,Hubei 430100,China)

机构地区：[1]长江大学石油工程学院,湖北武汉430100 [2]油气钻采工程湖北省重点实验室(长江大学),湖北武汉430100 [3]油气钻完井技术国家工程研究中心,湖北武汉430100

出　　处：《西安石油大学学报（自然科学版）》2024年第4期34-40,共7页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：科技部外国专家局外国专家重点支撑计划项目“表面修饰纳米二氧化硅/温敏聚合物复合材料开发及在非常规油气增产液中的应用”(WGXZ2022057)。

摘　　要：蒙脱石水化是导致钻井过程中井壁失稳的重要原因,小分子胺常被用做钻井液抑制剂来抑制蒙脱石的水化,但小分子胺的抑制剂作用机理基本是通过对抑制性能的评价来间接验证和分析的。为了深入揭示小分子胺的抑制剂作用机理,本文利用分子动力学的方法建立小分子胺-蒙脱石的分子动力学模型,通过模拟动态抑制过程,计算水分子的均方位移、抑制剂的径向分布函数、体系的能量和蒙脱石力学参数来研究小分子胺的抑制剂作用机理。结果表明:可视化的动态抑制过程显示小分子胺占据水分子原本吸附位点,分子中部的疏水基团阻止水分子在一定范围内接近蒙脱石表面;均方位移表明小分子胺的加入抑制的水分子的扩散,并且在水化后期小分子胺抑制效果更好;径向分布函数图显示,羟甲基比胺基更易与蒙脱石表面裸露的氧原子吸附,而小分子胺中的胺基降低了蒙脱石表面的负电荷密度;体系能量变化显示,在水化后期小分子胺与蒙脱石表面的相互作用更强;力学参数变化显示,在小分子胺加入后,蒙脱石的弹性模量、剪切模量、杨氏模量变大,提高了蒙脱石晶体的结构稳定性。The hydration of montmorillonite is an important cause of wellbore instability during drilling.Small molecule amines are often used to inhibit the hydration of montmorillonite in drilling fluids.In order to reveal the action mechanism of small molecule amine inhibitors in depth,a molecular dynamics model of small molecule amine-montmorillonite was established using molecular dynamics.The inhibition mechanism of small molecule amines was studied by simulating the dynamic inhibition process and calculating the mean square displacement of water molecules,the radial distribution function of inhibitors,the energy of the system and the mechanical parameters of montmorillonite.The visualized dynamic inhibition process shows that small molecule amines occupy the original adsorption sites of water molecules,and the hydrophobic groups in the middle of the molecules prevent water molecules from approaching the surface of montmorillonite within a certain range.The mean square displacement indicates that the addition of small molecule amines inhibits the diffusion of water molecules,and the inhibitory effect of small molecule amines is better in the later stage of hydration.The radial distribution function graph shows that hydroxymethyl more easily adsorbs the exposed oxygen atoms on the surface of montmorillonite than amino group,while the amino group in small molecule amines reduces the negative charge density on the surface of montmorillonite.The energy change of the system shows that the interaction between small molecule amines and the surface of montmorillonite is stronger in the later stage of hydration.The changes in mechanical parameters of montmorillonite show that after the addition of small molecule amines,the elastic modulus,shear modulus,and Young's modulus of montmorillonite increase,improving the structural stability of montmorillonite crystals.

关 键 词：钻井液 蒙脱石 水化膨胀 水化抑制剂 小分子胺 分子动力学模拟 

分 类 号：TE254[石油与天然气工程—油气井工程]