Injection of a heavy fluid into a light fluid in a closed-end pipe

Abstract

We report experimental results on the injection of a heavy fluid into a light one in a closed-end pipe, inclined at intermediate angles. The injection of the heavy fluid is made using an inner duct with a smaller diameter than that of the pipe in which the light fluid is placed. The fluids used are miscible and Newtonian, and they have the same viscosity. Our observation shows that, during the removal/replacement of the light fluid by the heavy fluid, at least four distinct flow stages can be identified: (i) initial buoyant jet of the heavy fluid, (ii) development of a mixing region, (iii) slumping flow of the heavy fluid, and (iv) heavy fluid front reaching the pipe end and returning toward the mixing region. Using high-speed camera images along with the ultrasound Doppler velocimetry and laser induced fluorescence data, the flow characteristics in these flow stages are quantified, and they are described in detail vs the dimensionless groups that govern the flow dynamics, namely, the Froude number (Fr), the Reynolds number (Re), the Archimedes number (Ar), and the pipe inclination angle (β). While our findings are of fundamental importance, they can also be used to provide a fluid mechanics understanding of the dump bailing method in the plug and abandonment (P&A) of oil and gas wells.

An experimental study of buoyant jets : effects of viscoplasticity

“…After the cessation of its operational lifespan, a well must be thoroughly sealed and decommissioned to avoid the potential for uncontrolled leaks that may harm fragile marine habitats [12,13]. A common method for achieving this is to inject a cement slurry into the wellbore, which subsequently dries and acts as a solid barrier [14,15]. In preparing the well for the placement of a cement plug, the clearance of the site is a crucial aspect of P&A operations, for which the jet cleaning technique has been developed as a recent innovation [6].…”

Viscoplastic fluid displacement flow in pipes : the effects of pipe axial

“…A displacement flow simply describes removing/displacing an in-place fluid by injecting another fluid with different properties. Such a flow has been widely investigated in confined geometries, such as pipes, for both Newtonian and non-Newtonian fluids [2,3,4]. Besides the rheological effects of the fluids, many effective parameters such as the viscosity and density of the fluids (in other words the physical properties of the fluids), the geometry configuration (pipe, annulus, etc.…”

From breakup to coiling and buckling regimes in buoyant viscoplastic injections

“…For instance in the dump bailing method, which is a widely used P&A process, a heavy viscoplastic cement slurry is injected (via an eccentric inner pipe) into a long circular casing to remove in situ light Newtonian fluids (typically water) and seal the wellbore (Nelson & Guillot 2006). We have recently studied in detail such injection flows, albeit for Newtonian fluids (Akbari & Taghavi 2020, 2021), finding highly dispersive flows. However, to realistically analyse industrially relevant flows, structured viscoplastic fluid flows must be considered.…”