MULTI-PHASE FLOW-MONITORING WITH AN OPTICAL FIBER DISTRIBUTED ACOUSTIC SENSOR

摘要

Embodiments of the invention provide a "tool-kit" of processing techniques which can be employed in different combinations depending on the circumstances to monitor multiphase flow in a structure such as a pipe. For example, flow speed can be found using eddy tracking techniques or by using speed of sound measurements. Moreover, composition can be found by using speed of sound measurements and also by looking for turning points in the k-omega {k-ω) curves, particularly in stratified multiphase flows. Different combinations of the embodiments to be described can therefore be put together to meet particular flow sensing requirements, both on the surface and downhole. Once the flow speed is known, then at least in the case of a single phase flow, the flow speed can be multiplied by the interior cross-sectional area of the pipe to obtain the flow rate. The mass flow rate can then be obtained if the density of the fluid is known, for example once the composition has been determined.