钻井液流变模式计算及优选

目前在计算钻井液流变参数时多采用线性最小二乘法方法进行求解,但是对于钻井液的非线性模式,线性最小二乘法改变了求解目标,使得计算结果不具有方差最小的特点。针对钻井液常用的三种非线性模式,分别提出了近似非线性最小二乘法的计算方法,该算法与非线性最小二乘法相比具有不需要设定初始计算值以及计算速度快的优点,同时与最小二乘法相比计算精度高。它可以应用到钻井液流变参数的确定、钻井液流变模式的优选等方面。

Calculation and Optimization of Drilling Fluid Rheology Model YUAN Liu Yan-xin Wang Han-xiang

The accurate calculation of rheological parameters during drilling fluid rheological model is the premise of drilling fluid optimization design. At present, the linear least square method is most commonly used during the calculation. However, this method changes the statistical characteristics of measurement error, and the calculation results do not have the feature of minimum variance. A new approximate nonlinear least square method is proposed according to three nonlinear rheological equations. This method possesses the advantages of high speed and high accuracy. It can be applied to the determination of drilling fluid rheological parameters and optimization design of drilling fluid rheological model.