寡聚糖在钻井液中的作用效能研究

Efficacy of oligosaccharide in drilling fluid

目前在复杂油气藏钻探领域中,现有钻井液体系组分多,性能调控难度大,成本高,且难以兼顾环保要求,因此迫切需要研发兼具多功能的环保型处理剂。基于上述需求,通过室内实验,考察了寡聚糖处理剂(MQ)在水基钻井液中的作用效能,并通过表面张力和接触角分析对其作用机理进行了初探。研究结果表明:①寡聚糖处理剂(MQ)分子能显著提高水基钻井液的液相黏度且同时增强了黏土颗粒空间网架结构的强度,表现出增黏提切、降低水分子滤失之功效;②寡聚糖处理剂(MQ)分子上的环多羟基易吸附在黏土颗粒表面上并形成较丰厚的外表面疏水的水化膜,使它同时起到润滑、抑制水化和致密化泥饼而降低滤失作用;③寡聚糖处理剂(MQ)在钻井液中增黏提切和降滤失作用的耐温极限为150℃;④寡聚糖处理剂(MQ)在水基钻井液中的抗温作用效能优于原有的黄原胶等聚合糖类处理剂。

Existing drilling-fluid systems used in complex oil and gas reservoirs have many components,leading to some difficulty or high cost in performance improvement from the perspective of environmental protection.Thus,it is very urgent to develop another multifunctional and environment-friendly agent.In this study,the efficacy of an oligosaccharide treatment agent(MQ)in water-based drilling fluid was investigated through laboratory experiment,and its acting mechanism was identified by analyzing surface tension and contact angle.Results show that(1)the MQ molecule can significantly increase the liquid-phase viscosity in water-based drilling fluid and enhance the strength of the spatial network structure of the clay particles in the drilling fluid,presenting the functions for increasing viscosity and dynamic shear and reducing water molecular filtration;(2)the cyclic polyhydroxyl group on the MQ molecule is easily adsorbed on the surface of clay particles to form a thicker hydrophobic hydration film,which can act as lubrication,hydration inhibition,and mud cake densification to reduce fluid loss;and(3)the temperature resistance limit of the MQ in drilling fluid is 150℃;and(4)the temperature resistance of the MQ in water-based drilling fluid is better than that of the original glycan treatment agent such as flavogen gel.