强抑制高润滑丙三醇基钻井液体系研究与性能评价

Study and Performance Evaluation of a Glycerol-Based Drilling Fluid System with Strong Inhibition and High Lubricity

  • 摘要: 针对油基钻井液存在污染环境、环保处理工艺复杂和影响录井质量等问题,利用低碳醇具有强抑制性和高润滑性、能与水以任意比例互溶的优点,开发了适用于强水敏性地层的丙三醇基钻井液。考察了膨润土在不同低碳醇溶液中浸泡24 h后的膨胀率,据此优选丙三醇做为抑制润滑剂;丙三醇体积分数越大,丙三醇溶液的抑制性、润滑性越好,黏度越高。为了降低丙三醇的用量和提高抑制性,将30%丙三醇溶液与5%KCl复配作为基液,形成了丙三醇基钻井液。性能评价结果表明,丙三醇基钻井液的抑制性、润滑性与油基钻井液接近,抗温140 ℃,抗NaCl、CaCl2及钻屑污染,放置180 d后性能稳定,可重复使用;提高丙三醇加量,还可以进一步增强其抑制性和润滑性。丙三醇基钻井液对于强水敏性地层或对润滑性要求较高的地层具有较好的应用潜力,也为开发环保钻井液提供了新的方向。

     

    Abstract: To address the problems of oil-based drilling fluid, such as environmental pollution, complex environmentaltreatment process and impact on logging quality, a glycerol-based drilling fluid suitable for strong water sensitive strata was developed for low-carbon alcohols strong inhibition, high lubricity and miscibility with water in any ratio. The swelling rate of bentonite in low-carbon alcohols solution for 24 h was investigated, and glycerol was selected as the optimal inhibition lubricant. The higher the volume fraction of glycerol, the better the inhibition, lubricity and viscosity of glycerol solution. In order to reduce alcohol consumption and further improve the inhibition, a glycerol-based drilling fluid system was formed by using 30% glycerol mixed with 5% KCl. The results of the performance evaluation show that the inhibition and lubricity of glycerol-based drilling fluid system are similar to those of oil-based drilling fluid, with temperature resistance of 140 ℃ and antipollution of NaCl, CaCl2 and drill cuttings. After six months of storage, the drilling fluid has achieved stable performance and can be reused. The inhibition and lubricity of drilling fluid can be further improved by increasing the dosage of glycerol. Glycerol-based drilling fluids can be used in strong water-sensitive stratum or with high requirement of lubricity. It shows a great application potential and this study also provides a development trend in environmental friendly drilling fluids.

     

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