应用马氏漏斗测定钻井液流变参数

Measure Rheology of Drilling Fluids with Marsh Funnel Viscometer

马氏漏斗通常仅仅能表征钻井液的平均黏度,无法表征钻井液的其他流变参数。为此,基于马氏漏斗测定原理,测量不同体积钻井液流出马氏漏斗所需的时间,建立马氏漏斗中钻井液的剪切应力随剪切速率的变化关系,并最终给出了钻井液流变参数(表观黏度、塑性黏度、动切力)的关系式。最后应用具体实例,通过测量2种组分不同的钻井液体系的流变参数,进一步阐述了应用马氏漏斗测量和计算钻井液流变参数的步骤和过程。

Marsh funnel viscometer is widely used in field measurement of the viscosity of drilling fluid. Though simple and cheap, the Marsh funnel can only measure the parameter that characterizes the average viscosity of drilling fluids. Based on the working principle of Marsh Funnel, the relationship of change in shearing stress and change in shear rate of mud in the Marsh funnel was calculated by measuring the time spent by the mud flowing out of the funnel, and an equation characterize the relation among apparent viscosity, plastic viscosity and yield point. By measuring two drilling fluids of different compositions, the procedure and process of using Marsh funnel to measure and calculate the rheological parameters were demonstrated.