以钠蒙脱土分散液作为模拟钻井液,与支化聚乙烯亚胺聚合物溶液交替流过模拟井壁(硅片),模拟生物矿化过程,进行层层沉积模拟实验.通过原子力显微镜、扫描电镜、红外光谱、X射线衍射等手段跟踪钠蒙脱土/聚乙烯亚胺复合膜的成膜过程,并表征复合膜的形貌、微观结构、化学组成及力学性能.结果表明,钠蒙脱土和聚乙烯亚胺可自发在模拟井壁上形成结构致密的有机/无机复合膜,该复合膜具有明显的层状结构,平均每层厚度约为46.18nm.该复合膜力学性能优良,而且杨氏模量并不随沉积层数的增加而变化.通过动态滤失实验表明,层层沉积改善了滤饼质量,降低了滤失速率以及总的动态滤失量,有助于井壁稳定.%The layer-by-layer deposition was carried out to simulate biomineralization process by using sodium montmorillonite (MTM) dispersions (as simulated drilling fluid) and branched polyethylenimine (BPEI) polymer solution flowing through simulated borehole wall (silicon wafer) alternatively.The forming process of BPEI/MTM composite films was characterized through atomic force microscopy,scanning electron microscopy,infrared spectroscopy and X-ray diffractometer.Surface morphology,composite film microstructure,chemical composition and mechanical properties of the films were also characterized.The results showed that MTM and BPEI can spontaneously form a dense organic/inorganic composite films on the simulated borehole wall,which showed obvious layer structure and the average thickness of each layer was about 46.18 nm.The composite films exhibited good mechanical properties,and the Young's modulus did not vary with the increase of deposited layers.The dynamic filtration experiment showed that layer-by-layer deposition can improve the filter cake quality,reducing the filtration rate and the total dynamic filtration,which is helpful to the stability of the borehole wall.
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