Pore-to-Field Upscaling of Immiscible Two-Phase Flow

Hasan Nooruddin Martin BluntJan 2015

Outline

• What is upscaling?• Why to scale-up multiphase flow properties? • Upscaling methods – brief background• How are we going to upscale multiphase flow?

What is upscaling?

• Upscaling is a process to determine effective multiphase flow properties on larger scales while capturing small-scale heterogeneity.

(Rhodes et al. 2008)

Introduction

Relative Permeability Capillary Pressure

• Field-scale reservoir simulation study always suffer from a shortage of SCAL data.• Pore-network modelling provides a practical tool to generate large datasets of physically-consistent

multiphase flow properties relatively quickly.• We need to scale-up this information to a field-scale reservoir simulation gridblock.

• to include other heterogeneities found at larger scales.• to address the impact of fluid forces acting at larger scales (e.g., impact of global boundary

conditions)

Why do we need to upscale pore-scale multiphase flow ?

• If it is not the REV:• We need to include other heterogeneities at larger scales.

• Assuming REV:• We need to address the impact of fluid forces acting at larger scales (e.g., impact of global

boundary conditions)

Upscaling approaches

• Steady-state • Unsteady-state (Dynamic methods)

Steady-state method

• Computationally cheaper than dynamic methods

• Key issue is to find the saturation distribution• CL: constant capillary pressure • VL: constant fractional flow• CL+VL: simulate until steady-state is reached – similar to dynamic method

• Apply sequence of single-phase simulations• Repeat the process at different average

saturations

Unsteady-state method

• Require running the fine-gridded model – Computationally demanding

• Account for numerical dispersion• Case dependent – have to be reproduced for

different flood rates and directions.• Might generate unphysical relative

permeability curves (non-monotone flux)

Our approach

mm scale

cm scale

m scale

Facies-model scale

• Multistage approach starting from an accurate representation at the pore level.• Pore-network model:

• capillary-controlled displacement – valid for most conditions at pore level.• good starting point – does not depend on BC.

• Incorporate pore-, core-, intermediate-, and large-scale heterogeneities, as required.• Including the right balance of forces at each stage.• Represent physics and geology.

Thank You

Thank you

Our approach

• We need to develop a simulator: • Incompressible , two-phase flow

simulator • Includes viscous, capillary and

gravitational forces• Unstructured – to effectively capture

heterogeneities at all upscaling stages

(Rhodes et al. 2008)