Institutional Digital Repository (Indian Institute of Technology Kharagpu)

Pati, Preeti Samhita

Resource Allocation Schemes for Diverse Service Requests in B5G Networks

Singh, Sarishti

Some Properties of Interval Matrices and Applications

Vishwakarma, Abhilash

Detection, Localization and Classification of Certain Rail Track Defects from Axle-Box Acceleration Measurements

Gaula, Ashok Kumar

Pricing and Quality Improvement Strategies in a Dual Collection Channel Closed-Loop Supply Chain

Kumar, Banty

Reduction Behaviour of Off-Grade Iron Ore Fines and Electric Arc Furnace Dust (EAFD)-Carbon Composite Pellets

Prasad G, Durga

Beneficiation of High Ash Indian Coals Through Combined Dry and Flotation Techniques

Singh, Pooja

PhD Thesis Title 
Interfacial instability in porous medium flow: Influencing factors of viscous fingering 
Candidate Name: Pooja Singh 
Roll No.: 18CH91R09
Abstract 
The immiscible and miscible fluid–fluid displacement in porous media is of great importance 
in several scientific and engineering applications, such as enhanced oil recovery (EOR) and 
CO2 geo-sequestration. When a low viscosity fluid replaces a high viscosity fluid in porous 
media, an interfacial instability occurs known as viscous fingering, also known as Saffman-
Taylor instability, which reduces the efficiency of the displacement process. Numerous 
investigations have been conducted to stabilize and control the viscous fingering phenomenon 
in both immiscible and miscible displacement, the majority of these studies have considered 
Newtonian fluid. However, due to the complex behavior of non-Newtonian fluids, studies on 
interfacial instability considering non-Newtonian fluids are still being explored. In this thesis, 
viscous fingering instability problem is studied considering the non-Newtonian fluid 
displacement. We present the study of viscous fingering in a radial Hele-Shaw cell in shear-
dependent rheological fluid, which transitions from the Newtonian to shear thinning behavior 
at low shear rates for different constant flow rates of the injection fluid and gap thickness. The 
viscous fingering characteristics such as side branching, growth of second-generation fingers, 
and inhibition of tip splitting are observed in the case of shear-thinning flow regime, both 
experimentally and numerically. The stability of the fingering at ultra-low flow rates exists 
much beyond that predicted by linear stability analysis.  We propose a quantitative criterion 
from the linear stability analysis involving non-Newtonian (shear-thinning fluid) to control the 
pattern formation and suppress viscous fingering controlling a parameter, which is a function 
of the physical and operating conditions. It is possible to stabilize the interface following a 
non-linear injection rate, 𝑄 ∼ 𝑡−(2−𝑛)⁄(2+𝑛), which is related to the displaced fluid rheology (n
: power-law index). Furthermore, we have experimentally shown a feasible approach toward 
long-term fingering stabilization with the continuous cyclic time-dependent injection flow rate. 
We experimentally investigate the interplay and transition of viscous fingering and fracturing 
for a shear-thickening fluid. We have used cornstarch suspension of different compositions and 
the rheology of the suspension exhibits shear thickening behavior beyond a critical shear rate. 
The evolution from viscous fingering to dendritic fracturing morphology is observed. The 
displacement efficiency of the process can be computed based on the fraction of injected phase 
to displaced phase as a function of injected volume for different weight fractions of cornstarch 
suspension. The viscous fingering pattern in 2D media can be significantly different from the 
3D pattern as it depends on the geometrical arrangements of the granular structure and flow 
connectivity in the pore network. However, fingering patterns in the three-dimensional (3D) 
scenario is different than the 2D case, on account of the gravitational segregation being more 
effective in 3D porous media. The displacement of the denser fluid by the less dense fluid 
creates a gravitational tongue, inducing a non-uniform interface that diminishes the 
displacement efficiency. The interaction between viscous fingering and gravitational 
segregation is observed in different fields, including hydrocarbons recovery, carbon-dioxide 
(CO2) sequestration, saltwater aquifer intrusion, and groundwater pollution. We study the 
three-dimensional viscous fingering morphology to investigate the effect of fluid miscibility 
and porous medium permeability using the X-ray micro-computed tomography (micro CT) 
technology. The phase miscibility of the injection fluid to the displaced fluid affects the 
fingering phenomena, transitioning from dispersion limited to diffusion. The areal sweep 
efficiency for miscible flow is high in comparison of immiscible flow. We have used the fractal 
analysis to analyse the complex patterns, and the fractal dimension is related to the process 
conditions. We report 3D diffusion-limited aggregation simulations to obtain patterns similar 
to the miscible fingering patterns and provide insights into the pattern growth behavior. The 
multiphase flow during the steam as well as CO2 injection EOR method can affect the viscous 
fingering. The coexistence of vapor and liquid in the displacing phase induces anisotropy and 
heterogeneity in the viscous fingering pattern, markedly distinctive from the classical 
observations in Hele-Shaw cell experiments and exhibits non-intuitive pattern formations. 
Therefore, the experimental investigation focuses on immiscible displacement within a radial 
Hele-Shaw cell using a phase-changing medium. The high viscosity oil is displaced by low 
viscosity methanol vapor, along with its condensate at different injection pressure. The thermal 
front movement is impeded due to heat transfer between the fluids as well as the large time 
scale of thermal diffusion to the other side of the observation window (quartz glass), causing 
the thermal front to lag behind the fluid front. Initially, momentum diffusion governs heat 
transfer, followed by thermal diffusion dominance. Interfacial oscillations induced by the 
Marangoni effect stemming from temperature-induced interfacial tension gradients are 
observed. Overall, the thesis objective is based on understanding and proposing engineering 
interventions to the complex problem of interfacial instability in the context of enhanced oil 
recovery technology.  
Keywords: Viscous fingering; Enhanced oil recovery (EOR); Radial Hele-Shaw cell; 
Saffman-Taylor instability; Non-Newtonian Fluid; Linear stability analysis; fracturing; 
Fractal dimension; Immiscible and miscible displacement; 3D viscous fingering; X-ray 
micro-computed tomography; Porous media flow; Diffusion-limited aggregation; 
Multiphase fluid flow 


Interfacial Instability in Porous Medium Flow: Influencing Factors of Viscous Fingering

Rupesh

Delineation of Geotechnical Properties of Subsurface Structures from Quasi-3d ERT Measurements

Gnanaguru, Mario Vino Lincy

A Comprehensive Study of Two-Dimensional Material-Based Heterojunctions for Photocatalytic Treatment of Broad-Spectrum Antibiotics

Shah, Adarsh Kumar

Multiscale Characterization and Modeling of 3D Printed Short Fiber Reinforced Thermoplastic Polymer Composites