Automated Fluid Rheology Measurement at the Drillsite

Abstract

Abstract With the increase of automation and process control requirements, a good real-time grasp of the drilling fluid rheology has repeatedly been flagged as a key requirement. Unfortunately, drilling fluid rheology is still mostly measured manually and reported only twice a day. Fluctuations in fluid composition and rheology due to wellbore/fluid interaction and temperature/shear/solids effects are generally missed. This paper describes the field implementation and testing of an inline-design pipe rheometer that operates autonomously to continuously measure rheological properties of the drilling fluid in the rig's mud tanks. This data can be used to monitor the stability or indicate changes in these drilling fluids. The system employs a progressive cavity pump to draw drilling fluid from the mud tank and propel it, at varying controlled rates, through two different sizes of pipe. Differential pressure transducers are used to measure the pressure drop over a fixed length in each size of pipe, and this data, along with flow rate, is used to calculate fluid viscosity. All components are installed within a standard ISO shipping container for ease of transport and deployment at the wellsite. It is positioned next to the mud tanks where it continuously samples and measures the drilling fluid. Field test results of the system are presented. The system was operated autonomously on location in Saudi Arabia for an entire drill stage (3.5 days) of 5-7/8" section for gas drilling. In this section, oil based mud was used and measured by the system. The system was controlled remotely via WiFi connection. During the test period, manual viscosity and density measurements were also taken using the Fann-35 and mud balance methods. Subsequent comparison shows excellent agreement between the automated and manual measurements.