| 微生物无固相钻井液体系构建及其固壁作用机理研究 |
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| 引用本文： | 李之军,朱茂,智晶子,韩毅,陈俊秀,赵淦.微生物无固相钻井液体系构建及其固壁作用机理研究[J].煤田地质与勘探,2023,51(4):187-194. |
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| 作者姓名： | 李之军 朱茂 智晶子 韩毅 陈俊秀 赵淦 |
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| 作者单位： | 1.成都理工大学 地质灾害防治与地质环境保护国家重点实验室，四川 成都 610059 |
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| 基金项目： | 国家自然科学基金青年基金项目(41702388)；成都理工大学珠峰科学研究计划(80000-2022ZF114111) |
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| 摘 要： | 钻探过程中，常遇到破碎性地层，容易发生井壁失稳而诱发井下复杂事故。增强破碎块之间的胶结力，提升井壁围岩力学强度，是解决该类地层井壁失稳的有效途径之一,微生物诱导碳酸钙沉淀(MICP)技术为实现这一途径提供了很好的借鉴。为此，通过实验研究，分析了巴氏芽孢杆菌在无固相钻井液体系中的生长情况，得到适合巴氏芽孢杆菌生长的无固相钻井液，由此构建微生物无固相钻井液体系。利用岩心浸泡实验和扫描电镜(SEM)分析方法，探讨了微生物无固相钻井液体系的固壁效果及其作用机理。结果表明：巴氏芽孢杆菌在由植物胶、聚丙烯酰胺(PAM)、羧甲基纤维素钠(CMC)组成且含有培养基的无固相钻井液中的生长情况最好，经过24 h的生长，600 nm波长处的吸光值(OD600)达到1.54。故确定微生物无固相钻井液体系的配方为：0.1%植物胶+0.1%PAM+0.1%CMC+巴氏芽孢杆菌(OD600=0.8)+0.25%氯化钠+1%尿素+0.75%酪蛋白胨+0.25%大豆蛋白胨。在微生物无固相钻井液体系中添加钙源，可以获得更好的固壁效果，固结后试样的抗压强度达到0.183 MPa。该体系的固壁机理是微生物在松散颗粒间诱导生成...
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| 关 键 词： | 破碎地层 井壁稳定 微生物诱导碳酸钙沉淀 巴氏芽孢杆菌 无固相钻井液 固壁机理 |
| 收稿时间： | 2022-07-09 |
Study on construction of microbial solid-free drilling fluid system and its borehole wall enhancement mechanism |
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| Institution: | 1.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China2.College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu 610059, China3.Sichuan Water Conservancy Vocational College, Chengdu 611231, China |
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| Abstract: | Broken formations are often encountered during drilling, which is prone to the instability of wellbore wall and induces serious downhole accidents. Enhancing the cementing force between the broken blocks and improving the mechanical strength of the surrounding rocks of a wellbore is one of the effective ways to solve the instability of wellbore in this type of formation, for which the microbially induced calcite precipitation (MICP) technology provides a good reference. To this end, the growth of Bacillus pasteurii in the solid-free drilling fluid system was analyzed through experimental study, and thus a solid-free drilling fluid suitable for its growth was obtained. Ultimately, a microbial solid-free drilling fluid system was constructed. Then, the effect of wellbore wall enhancement on microbial solid-free drilling fluid system and its mechanism were discussed using a core immersion experiment and scanning electron microscope (SEM) analysis methods. The results show that the most suitable environment for the growth of Bacillus pasteurii is the solid-free drilling fluid composed of plant gel, PAM, CMC, and culture medium, and the OD600 reaches 1.54 after 24 hours of growth. Therefore, it is determined that the formula of the microbial solid-free drilling fluid system is: 0.1% plant gel + 0.1% PAM + 0.1% CMC + Bacillus pasteuri (OD600=0.8) + 0.25% sodium chloride + 1% urea + 0.75% casein peptone + 0.25% soy peptone. Adding calcium sources to microbial solid-free drilling fluid can achieve a better effect of wellbore wall enhancement, and the compression strength of the consolidated specimen can be up to 0.183 MPa. Generally, the wellbore wall enhancement mechanism of this system is to generate calcium carbonate crystals under the induction of microorganisms in the loose particles and thereby fill in the pores, which enhances the cementation force between the loose particles so that the originally loose gravel soil could form an entirety, thereby enhancing the wellbore wall. |
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