改性天然高分子基钻井液研究

改性天然高分子基钻井液体系既能保护环境又能保护油气层且成本合理，该体系仅用4种主要处理剂即可满足勘探开发工程的需要。为此，室内评价了改性天然高分子基钻井液体系的主要处理剂：天然高分子包被剂IND30、天然高分子降滤失剂NAT20、无荧光白沥青防塌剂NFA25和干粉聚合醇润滑剂PGCS1等4种处理剂的抑制、流变、降滤失、环保、摩阻等主要技术性能。在此基础上，用此4种处理剂通过正交实验方法研制出了改性天然高分子基钻井液的基本配方，并评价了配方的抗温、抗污染、抑制分散、环保等主要性能。通过多个油气田百余口井的钻井应用表明，改性天然高分子基钻井液体系维护简单、处理方便，在稳定井壁、提高机械钻速、保护储层、环境保护等方面优点明显，值得进一步推广应用。

THE MODIFIED NATURAL-MACROMOLECULE DRILLING FLUIDS

The modified natural macromolecule drilling fluid system is not only friendly to environment, but also can control formation damage, and its cost is acceptable as well. This drilling fluid system only includes four kinds of primary additives to meet the engineering requirements of exploration and development, i. e., encapsulator IND30, filtrate loss reducer NAT20, non fluorescent anti caving additive NFA25 and polyol solids PGCS1. A laboratory test evaluated these four additives and their different qualities such as the inhibitivity, rheological properties, fluid loss control, toxicity, and friction resistance. And then based on these four additives by orthogonal experimental method, this study refined a new formulae of this modified natural macromolecule drilling fluid, and evaluated the performances of this formulae such as high temperature resistance, anti contamination capability, disperse inhibition capability, environment friendly features. Field applications in over 100 wells at different oilfields demonstrated that this drilling fluid system was very easy to maintain and convenient to handle, having remarkable effects in stabilizing wellbore, enhancing penetration rate, controlling formation damage, protecting environment and so on.