Development and Validation of a Rotating Wheel Coriolis Mass Flowmeter for Accurate Measurement of Drilling Fluid with No Pressure Loss

Abstract

Abstract Accurate measurement of the flow rate out of a well during drilling is essential for optimizing drilling performance and ensuring operational efficiency and safety. In conventional drilling, a flowmeter placed in the return flowline shall not introduce pressure drops and shall work without being filled. A new concept using a rotating measuring wheel fulfills these two requirements. However, it needs to be verified that the concept is sufficiently precise over the wide range of flowrates that can be experienced during a drilling operation as well as being accurate for non-Newtonian fluids containing cuttings and gas. The measurement principle of the rotating wheel mass flowmeter involves directing the fluid, including cuttings and gas, through the center of a horizontal rotating wheel and collecting it via a funnel. The measuring wheel has vertical vanes onto which the drilling fluid applies a force due to the Coriolis acceleration. The forces on the vanes result in a torque that can be measured on the axle of the driving motor. This torque is directly proportional to the mass flowrate of fluid passing through the measuring wheel. To verify the accuracy of the sensor, a medium scale apparatus has been built and used in a flow-loop together with a high precision vibrating tube Coriolis flowmeter for reference. The test procedures consist of measuring flowrates with a range scale of 5 to 120 kilograms per minute with various drilling fluids. The medium scale apparatus successfully handled flow rates up to the expected operational limit with optimal rotational speeds identified for different flow rates. The experiments encompassed various fluids, including water, glycerin (representing high-viscosity Newtonian fluid), and non-Newtonian drilling fluid samples. During the tests, issues related to design, instrumentation, and control system were identified and addressed. The results of the tests confirm that the rotating wheel mass flowmeter establishes a linear relationship between torque and mass flow rate, and that this linear relationship is valid both at low and high rotational speeds. The benefits of this new mass flowmeter include acceptable accuracy and reduced maintenance requirements, and is also functional at very small rates, compared to traditional methods like the flow paddle. This research represents a significant step towards the development of a full-scale device, supporting an agile development process in the field of digitalization and automation of drilling operations.