Abstract Traditional methods of rheological and density measurements using offline devices require manual intervention and are prone to human error. Additionally, decision-making relies on fluid property data that may be several hours old. Automating the drilling fluid measurement process enables drilling engineers to access real-time, reliable fluid data when making critical decisions. This paper presents recent advancements in the development of a real-time drilling fluid measurement unit, which minimizes safety risks for operators while providing accurate, consistent, and automated measurements of drilling fluid properties. The unit continuously measures drilling fluid density, rheological parameters, temperature, and pH at a frequency suitable for critical decision-making. The compact system (1 m × 0.7 m × 0.9 m) consists of a circulation system, a measurement system, and a control system that supports both automatic and manual operation. A self-cleaning module ensures proper cleaning between cycles and allows quick switching between oil-based and water-based fluids. Fluid density is measured using an insertion type sensor on a static column, while rheology is determined using an automated Couette viscometer with variable speeds. A prototype was first built and tested in the laboratory before being deployed to an offshore well. During field deployment, the unit collected and monitored parameters for several days using oil-based drilling fluid, and the results were compared with traditional offline instruments. The automated measurements showed close agreement with offline methods. Since the initial deployment, multiple units have been deployed, demonstrating reliable continuous operation with minimal error. The unit's outputs can be integrated into an in-house drilling hydraulic simulator to predict circulating pressures. A case study illustrates the application of the measured data alongside the hydraulic simulator to monitor equivalent circulating density (ECD) in a drilling well. Predicted ECD values were compared with pressure-while-drilling (PWD) measurements over a 1600-meter interval. The results show that the predicted ECD closely follows the PWD trendline, with an average error of about 1%. This paper presents the results and lessons learned during the development of an in-line mud measurement unit, which enables continuous and accurate monitoring of fluid properties. It also provides a comparative analysis of in-line and offline measurements. The integration of the unit's measurements with a hydraulic simulator yields promising results for real-time ECD tracking during drilling operations.
Ma et al. (Mon,) studied this question.