Real-time Optimization Method of Drilling Fluid Rheological Model Based on Pipe Viscosity Measurement

The rheology of drilling fluid is crucial for bottom hole pressure control, hydraulic fracturing, and wellbore stability. Currently, manual methods like rotational viscometers are used on drilling sites, which have long measurement cycles and are prone to human interference. Existing online measurement devices with pipe viscometers are affected by fluid pulsation from diaphragm pumps and motor vibrations, making it hard to accurately determine and monitor rheological parameters in real-time. To address these issues, this paper proposes a real-time optimization method for the rheological model of drilling fluid based on a pipe viscometer. First, the rheological model of drilling fluid and the calculation method for piep viscometer parameters were analyzed, and a pulsation interference suppression model for the pressure difference in the rheological measurement pipe based on empirical mode decomposition was established. Then, preprocessing and regression analysis of the drilling fluid rheological model were carried out, and a real-time optimization method based on univariate linear regression and the golden section search algorithm was constructed. Finally, an experimental platform for online monitoring of drilling fluid rheology using a single measuring pipe was set up. Experimental results show that the proposed method effectively suppresses pulsation interference on the pressure difference in the measuring pipe. The shear stress-shear rate rheological model curve of the drilling fluid better matches the manual rotational viscometer parameters compared to directly measured parameters. The real-time optimization accuracy of the drilling fluid rheological model exceeds 95%, significantly improving the real-time measurement accuracy of drilling fluid rheological parameters.