纳米颗粒矿化沉积及提高钻井井壁稳定性

Mineralized Deposition of Nanoparticles and Its Application on the Improvement of Wellbore Stability

刘振东 徐海 李公让 张敬辉 吕建仁

LIU Zhendong XU Hai LI Gongrang ZHANG Jinghui LYU Jianren

在泥页岩地层的钻井中，由于页岩极易吸水膨胀，导致井壁出现掉块、坍塌等情况，因此在钻井过程中需要对井壁进行加固。模拟生物矿化沉积过程，在硅片表面交替沉积纳米颗粒和阳离子聚合物，形成纳米矿化沉积层。对纳米颗粒和阳离子聚合物进行了优选，通过原子力显微镜、扫描电子显微镜分析沉积层的表面和断面形貌，通过红外光谱仪分析沉积层的组成，研究了沉积层的机械性能。结果表明，方解石晶型纳米碳酸钙的沉积效果优于纳米二氧化硅，低浓度纳米碳酸钙的沉积效果优异。硅片在1%阳离子聚合物支化聚乙烯亚胺与0.4%纳米碳酸钙中交替沉积可形成均匀分散、致密牢固的“堆砌”结构。沉积达到25 个循环时，沉积层厚度为23.88 μm，横向拉伸杨氏模量为1.4086 MPa，具有较好的黏弹性。改性纳米碳酸钙和阳离子聚合物可在模拟井壁上形成致密稳定的沉积层，为加固井壁、提高井壁稳定性提供了新的思路。

In the drilling of mud shale formation，the shale is very easy to absorb water and expand，resulting in block falling and collapse of well wall. Therefore，the well wall needs to be reinforced during drilling process. Simulating the biomineralization deposition process，nanoparticle and cationic polymer were alternately deposited on the surface of silicon wafer to form nano mineralized deposition layer. Nanoparticle and cationic polymer were optimized. The surface and cross-section morphology of deposited layer were analyzed by atomic force microscope and scanning electron microscope. The composition of deposited layer was analyzed by infrared spectrometer，and the mechanical properties of deposited layer were studied. The results showed that the deposition effect of nano calcium carbonate was better than that of nano silica，and the deposition effect of nano calcium carbonate with low concentration was excellent. A uniformly dispersed，dense and firm“mud brick stacking”structure was formed after silicon wafer deposited alternately in 1% cationic polymer（branched polyethyleneimine）and 0.4% nano calcium carbonate. When the number of deposition cycles reached 25，the thickness of deposition layer was 23.88 μm and the transverse tensile Young’s modulus was 1.4086 MPa，showing good viscoelasticity. Modified nano calcium carbonate and cationic polymer could form a dense and stable sedimentary layer on the simulated well wall，which provided a new idea for strengthening and improving the stability of well wall.

10.19346/j.cnki.1000-4092.2022.02.002