Empirical Correlation to Predict Viscosity Breaking Ratio of Guar-Based Biodegradable Drilling Fluid

Four kinds of hydroxypropyl guar and three types of special enzyme were utilized to make different guar-based biodegradable drilling fluids. Apparent viscosities and viscosity breaking ratios with the lapse of time were recorded in each test. The paper adopted a couple of nonlinear regression models to fit the plots of viscosity breaking ratio versus time. Data Processing Software, a convenient and easily handled data processing tool, was introduced to screen optimal models and determination coefficient R
²
, levene F and significant level p were used as main regression parameters. Compared to other models, Michaelis Menten correlation shows the best fitting performance. With this model, we can get the apparent viscosity and viscosity breaking ratio at any given time. This empirical formulation can give good guidance to the implement of guar-based biodegradable fluids in drilling, completion or stimulation of coalbed methane industry.