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Constant pressure invasion of viscoplastic suspensions in thin conduits Izadi, Mahdi


This thesis presents a numerical study of the flow and stoppage of a viscoplastic fluid invading into a thin, non-uniform channel. The fluid represents a cementitious sealant, and the invasion aims to regulate gas flow through the partially filled channel. The flows are driven under constant pressure and arrested due to fluid yield stress. The gas flow through the channel, modeled as a Hele-Shaw cell, is calculated using a thin gap approximation and computed before and after the invasion. Motivated by industrial applications from squeeze cementing, the first objective is to investigate the fluid interface morphology at the stoppage, i.e., how effectively the fluid blocks the gap. We present a gap-averaged framework to study the interface morphology for radial injection into a Hele-Shaw geometry, where the gap thickness variations are defined using realistic industrial data and a stochastic model. We quantify the interface morphology to investigate the effect of different parameters. Our results reveal an enormous variability resulting from the geometrical uncertainties. The second objective of the thesis is to devise a gap-averaged model for a multisource injection, where the fluid is injected into the Hele-Shaw geometries from patterned injection points. We develop a method by stacking radial injection scenarios to reconstruct the whole section. We investigate the effect of perforation patterns and rheological parameters on the leakage flow rate. We generate a probability distribution of leakage rates to estimate the mean reduction in flow leakage and compute confidence intervals. Our results suggest that higher perforation density and lower yield stress slurry lead to higher success rates. The final objective of this thesis is to study the invasion of a viscoplastic suspension into a thin channel. We consider the multiphase nature of the suspension and compute the transverse distribution evolution of liquid and solid phases during flow. The aim is to explore various phenomena, such as particle migration, jamming, and yield surface position. This allows us to validate the accuracy of gap-averaged models, i.e., how ignoring transverse flow parameters affects penetration depth estimation. It also points toward new and more complex physical models for processes such as squeeze cementing.

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Attribution-NonCommercial-NoDerivatives 4.0 International