On-Line Measurement Method for Rheology of Straight Tubular Oil-Based Drilling Fluid Under Pulsating Flow

With the rapid development of drilling automation, how to automate real-time online measure drilling fluid rheology accurately has become one of the problems that the industry urgently wants to solve. At present, the common method is the rheological measurement method of straight pipe drilling fluid, but often the pumping equipment will produce pulsating flow during reciprocating pumping, resulting in a large error in the data of pressure difference and flow measurement, and the corresponding rheological parameters obtained are not accurate. In order to solve the problem of low accuracy of rheological parameters, this paper proposes an online measurement method for the rheology of straight tubular oil-based drilling fluids under pulsating flow, and firstly establishes an online measurement model of the rheology of straight tubular oil-based drilling fluids. Then, fluent is used to simulate and analyze the fluid movement of drilling fluid with different rheology in the measuring tube, and then analyze the error of differential pressure measurement and flow measurement of the measuring tube under the fluctuating flow. The actual measurement environment was simulated as the initialization parameters of the fluent simulation, and the calibration model of the oil-based drilling fluid measured by the device under the influence of pulsation was established. Finally, the experimental bench was built, and the experimental results showed that the calculated rheological parameters were 2.69% for apparent viscosity (AV), 2.362% for plastic viscosity (PV) and 3.056% for yield point (YP), which effectively improved the online measurement accuracy of straight tube oil-based drilling fluid.