Measurement of the Flowrate Out of a Well for Conventional DrillingOperations

摘要

The flowrate out of a well is an important source of information for detecting gains or losses. Yet,many conventional drilling operations have only access to qualitative measurements from a flow-paddle.Quantitative flowrate out measurements can be obtained from a vibrating tube Coriolis flowmeter, but itusually requires regular cleaning to maintain an acceptable precision. This paper described a new designfor a flowrate out sensor that necessitates little maintenance and yet provides quantitative measurements. This new device is primarily a mass flowmeter that also utilizes Coriolis forces as the measurementprinciple. Unlike the vibrating tube mass flowmeter, the apparatus does not need to be filled with drillingfluid. Because of its measurement principle, cuttings cannot clog the apparatus and mud cannot form a layerat the surface of the instrument and therefore its precision stays unbiased for a long time. A small fraction ofthe return flow passes through a densitometer to obtain the mass density of the drilling fluid and thereforethe volumetric flowrate can also be provided.