30 May 2022 to 2 June 2022
Asia/Dubai timezone

The Transition from Connected to Disconnected Pathway Flow Regime : Understanding the Combined Effects of Wettability and Flowrate

2 Jun 2022, 14:45
15m
Oral Presentation (MS06-A) Physics of multiphase flow in diverse porous media MS06-A

Speaker

Rumbidzai Nhunduru (Heriot-Watt University)

Description

The contribution of pore-scale properties is often neglected in large scale (macro-scale) models describing subsurface fluid processes (1). Pore-scale flow properties, such as wettability have a significant impact on macro-scale flow functions, such as relative permeability, capillary pressure, saturation distribution and displacement efficiency (2). Upscaling multiphase flow from Pore-to-Darcy scale is one of the largest unresolved problems in the field of porous media research that has attracted the interest of many researchers for decades (3). One of the key challenges is addressing connected and disconnected fluid fractions (4)(5).
In this work, the combined effects of wettability and fluid flowrate on dynamic fluid connectivity and the saturation function are investigated. Direct numerical simulations involving immiscible displacement of decane by water were performed in a 2D digital model of a Berea sandstone rock. In all simulations performed, the Berea sandstone model was initially saturated with decane and then water was injected to displace it from the pore spaces. Invading fluid Darcy velocities investigated ranged from 0.03m/s (Ca= 5.45x10-4; Reynold’s number (Re) = 0.36) to 30m/s (Ca= 5.45x10-1; Re = 360). Wetting conditions investigated were for contact angles 45° (water-wet), 90° (neutrally-wet) and 150° (oil-wet).
Connected pathway flow (CPF) and two disconnected flow regimes were observed. The first disconnected flow regime was classified as ganglion dynamics (GD), where the invading fluid propagated through the pore network in the form of large, disconnected ganglia. The second disconnected flow regime was a drop traffic flow (DTF), where the invading fluid propagated throught the pore network as very small fluidic elements (droplets).
At the lowest capillary number (Ca= 5.45x10-4), the CPF regime dominated under the neutrally wet state whilst the GD flow regime dominated for the oil- and water-wet cases. A connectivity index (Λ) derived from the Euler characteristic (χ), a fluid topological descriptor, was used to track the temporal evolution of fluid connectivity as the simulations progressed. For all wetting conditions investigated, ganglia of the defending fluid became smaller and more disconnected with increasing flow rate. At the highest capillary number (Ca= 5.45x10-1), the DTF flow regime dominated for all wetting states. In cases where the GD regime dominated, low flow cohesion was observed between discrete ganglia whilst high flow cohesion was observed where the CPF regime was dominant. Although more discrete fluid elements were present in the DTF regime in comparison to the GD regime, higher flow cohesion was observed in DTF dominant cases. The transition from low cohesion to high cohesion flows was found to have a consequential effect on the kinetics of the displacement process and the shape of the saturation function. Displacement efficiency increased by up to 35% for highly cohesive flows in comparison to flows with low ganglion cohesion.
Acknowledgements
This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (MILEPOST, Grant agreement no.: 695070). This paper reflects only the authors’ view and ERC is not responsible for any use that may be made of the information it contains.

References

The role of phase topology and ganglion dynamics for two-fluid flow. Phys Rev E. 2016;94(4):1–10.
2. Zhao X, Blunt MJ, Yao J. Pore-Scale Modeling: Effects of Wettability on Waterflood Oil Recovery. J Pet Sci Eng [Internet]. 2010;71(3–4):169–78. Available from: http://dx.doi.org/10.1016/j.petrol.2010.01.011
3. Das DB, Hassanizadeh SM. Editorial. Upscaling Multiph Flow Porous Media From Pore to Core Beyond. 2005;1–4.
4. Alpak FO, Berg S, Zacharoudiou I. Prediction of Fluid Topology and Relative Permeability in Imbibition in Sandstone Rock by Direct Numerical Simulation. Adv Water Resour [Internet]. 2018;122(August):49–59. Available from: https://doi.org/10.1016/j.advwatres.2018.09.001
5. Rücker M, Berg S, Armstrong RT, Georgiadis A, Ott H, Schwing A, et al. From Connected Pathway Flow to Ganglion Dynamics. Geophys Res Lett. 2015;42(10):3888–94.

Participation Unsure
Country United Kingdom
MDPI Energies Student Poster Award No, do not submit my presenation for the student posters award.
Time Block Preference Time Block B (14:00-17:00 CET)
Acceptance of the Terms & Conditions Click here to agree

Primary author

Rumbidzai Nhunduru (Heriot-Watt University)

Co-authors

Amir Jahanbakhsh (Heriot-Watt University) Dr Krystian. L Wlodarczyk (Heriot-Watt University) Prof. M. Mercedes Maroto-Valer (Heriot-Watt University) Omid Shahrokhi (Heriot-Watt University) Dr Susana Garcia (Heriot-Watt University)

Presentation materials

There are no materials yet.