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| 无机盐对蒙脱石弹性力学参数影响的分子模拟与实验研究 |
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徐加放1,顾甜甜1,沈文丽2, 王晓璞1,马英文3,彭林1,李小迪1
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(1.中国石油大学石油工程学院,山东青岛 266580;2.中国石化工程建设有限公司,北京 100101;3.中海油天津分公司,天津 300452)
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| 摘要: |
| 利用分子模拟软件Materials Studio(MS)建立Na-蒙脱石的微观晶体结构模型,研究无机盐抑制蒙脱石的水化机制以及水化造成的蒙脱石弹性力学参数变化。将无机盐化学的影响结果体现在力学强度参数的变化,从而将井壁稳定的化学研究和力学研究耦合在一起。结果表明:Na-蒙脱石晶体的层间距随晶体表面吸附水分子个数呈跳跃式增大,岩石强度逐渐减小;无机盐通过控制蒙脱石层间水分子,实现了对蒙脱石水化的抑制作用,KCl、CaCl2和NaCl的最佳质量分数分别为:15.00％～20.00％、37.48％～43.50％和16.88％～19.16％;KCl和CaCl2对提高蒙脱石晶体弹性模量效果最好。 |
| 关键词: 井壁稳定 分子模拟 弹性模量 无机盐 膨胀 声波速度 |
| DOI：10.3969/j.issn.1673-5005.2016.02.010 |
| 分类号::TE 256 |
| 文献标识码:A |
| 基金项目:国家“973”项目(2015CB251206);中央高校基本科研业务费专项(14CX06030A,15CX02008A) |
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| Influence simulation of inorganic salts on montmorillonite elastic mechanical parameters and experimental study |
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XU Jiafang1, GU Tiantian1, SHEN Wenli2, WANG Xiaopu1, MA Yingwen3, PENG Lin1, LI Xiaodi1
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(1.School of Petroleum Engineering in China University of Petroleum, Qingdao 266580, China;2.SINOPEC Engineering Incorporation, Beijing 100101, China;3.Tianjin Branch of CNOOC, Tianjin 300452, China)
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| Abstract: |
| A Na-montmorillonite micro-crystal structure model was established using the Materials Studio molecular simulation software, and the chemical and mechanical models of borehole stability were coupled in order to study the mechanism of shale 's hydration, alongside with the changes in the elastic mechanical strength parameters during the hydration process and the inhibition mechanism of inorganic salts on hydration. The results show that the interlayer space of Na-montmorillonite followed a step-change increases and mechanical strength of montnorillonite decreases with the addition of water. The inorganic salts inhibit the hydration of montmorillonite via the control over water molecules at the interlayer, and the optimal concentrations are 15.00％-20.00％, 37.48％-43.50％ and 16.88％-19.16％ for KCl, CaCl2 and NaCl respectively. KCl and CaCl2 can significantly enhance the elastic modulus of montmorillonite crystal. |
| Key words: borehole stability molecular simulation elastic modulus inorganic salt swelling acoustic velocity |
