适用于高性能水基钻井液的纳米纤维素和生物聚合物研究

Study on Nanocellulose and Biopolymers for High Performance Water-Based Drilling Fluids

传统的高性能水基钻井液通常利用生物聚合物来达到提黏、悬浮固体以及控制井眼中的流体损失。为在日益苛刻的环境下扩大水基钻井液的应用范围,需采用有助于提高钻井效率、渗透率及提升水基钻井液体系在高温高压条件下的性能的新材料。其中纳米纤维素具备突出的机械、结构和热性能,在较低质量分数下增黏效果明显。以工业级牛皮纸浆为原料,以黄原胶、瓜尔胶等生物聚合物为增黏剂,在水性分散液中制备纳米纤维素CNF。通过观察流变性、分散稳定性及CNF与生物聚合物之间的协同作用可知,体系的黏度变化取决于与纳米纤维素共混的生物聚合物的类型,但与成分的质量平衡无关。在一些共混体系中,较低的生物聚合物质量分数便可增加共混体系的黏度,而其他共混体黏度却随质量分数增加而降低。基于此可将CNF与已经广泛用于水基钻井液的生物聚合物混合来达到提高体系性能目的,从而体系中可使用更少材料便可达到所需性能需求。

Traditional high-performance water-based drilling fluids usually use biopolymers to increase viscosity,suspended solids and control fluid loss in wellbore.In order to expand the application scope of water-based drilling fluid under increasingly harsh environment,new materials are needed to improve drilling efficiency,permeability and performance of water-based drilling fluid system under high temperature and high pressure.Among them,nanocellulose has outstanding mechanical,structural and thermal properties,and has obvious viscosifying effect at lower mass fraction.In this paper,nanocellulose CNF was prepared from industrial kraft pulp,xanthan gum and guar gum as tackifiers in aqueous dispersion.By observing the rheological properties,dispersion stability and the synergistic effect between CNF and biopolymer,it was found that the viscosity of the system depended on the type of biopolymer blended with nanocellulose,but had nothing to do with the mass balance of the components.In some blends,lower mass fraction of biopolymer could increase the viscosity of the blends,while the viscosity of other blends decreased with the increase of mass fraction.Based on this,CNF was mixed with biopolymer which has been widely used in water-based drilling fluids to improve body performance,so that less material could be used in the system to meet the performance requirements.