关键词: 钻井液, 流变参数, 流变模式, 高斯-牛顿法, 计算软件

Abstract: The determination of rheological parameters and the optimization of rheological pattern are the basis of drilling fluid design and circulating pressure loss calculation. For drilling fluid model of nonlinear rheological pattern，a regression model of nonlinear rheological pattern is established based on Gauss-Newton method and the readings of a six-speed viscometer. According to the relevant parameter R to measure the deviation relationship，matched computing software to select the rheological pattern for drilling fluid is developed with C# as the programming language，which outputs the rheological curve of each rheological pattern. Validation is also made by integrating with the measured data. The algorithm can determine the rheological parameters for drilling fluid of nonlinear rheological pattern，and select appropriate rheological pattern by comparing the correlation coefficient，which provides an effective tool for quickly selecting rheological pattern for drilling fluid.

Key words: drilling fluid, rheological parameters, rheological pattern, Gauss-Newton method; computing software