Method for optimizing the characteristics of an axial fluid circulation in a variable annular space around pipes

Abstract

The method according to the invention permits adapting for any fluid, a known model representative of the circulation of a fluid in an annular space around a motionless pipe, centered or eccentric uniformly over the total length thereof, to more complex cases which are encountered in practice and notably in drilling. The invention comprises the application, to the pressure loss values obtained with the known model, of a first correction factor accounting for the eccentricity variations which the pipe may undergo notably because of the variations in the axial load applied or of straightness defects of the conduit, and of a second correction factor representative of the effects due to the rotation of the pipe. The method identifies the prominent pressure loss variations which are observed in narrow annular spaces. The method can be applied to narrow hole petroleum drilling (of the slim hole type).

Dependencies are inferred from the claim text.