Pore-Scale Analysis of WAG Flooding V. Sander Suicmez Dr. Mohammad Piri Prof. Martin J. Blunt 5 Jan 2005 Centre for Petroleum Studies Department of Earth Science and Engineering Imperial College London

Outline  Introduction  What has already been done? Two- and three-phase pore-scale configurations  Two- and three-phase pore-scale configurations  Displacement mechanisms  Validation - comparison with experimental data  What is new?  New displacement mechanisms  More complicated saturation paths  A generic WAG study  Conclusions & Future Work

Introduction

What do we have? Piri, 2003 A three-phase flow simulator (incorporating geologically  A three-phase flow simulator (incorporating geologically realistic network model) with full extension of possible realistic network model) with full extension of possible generic configurations for any wettability. generic configurations for any wettability.  A robust clustering algorithm incorporating coalescence and break of trapped clusters. and break of trapped clusters.  Point-by-point comparison with data using saturation path tracking algorithm. path tracking algorithm.

One- and Two-Phase ConfigurationsWaterOil Gas

Three-PhaseConfigurationsWaterOil Gas

Example Displacement Sequence Configuration B Configuration A Configuration B Configuration A Configuration C Primary DrainageWater Flooding Gas Injection Configuration F Layer Collapsing Gas Injection Gas Water Oil

Saturation Tracking Oak data, Piri, 2003 Measured and tracked saturation paths

Oil Relative Permeability Piri, 2003

Gas Relative Permeability Piri, 2003

Water Relative Permeability Piri, 2003

Simultaneous Gas & Water Injection

Oil Relative Permeability

Water Relative Permeability

Gas Relative Permeability

Mobilising Oil by Double Displacement WaterOil Gas Trapped Oil

Double Displacements Gas Injection Gas Oil Water Gas Water Oil Water Injection Water Oil Gas Water Gas Oil Oil Injection Oil Gas Water Oil Water Gas

Multiple displacements in WAG Sorbie & van Dijke, 2001

A Generic WAG Study Spreading Oil Layers Weakly Water Wet (Oak’ s data)

WAG study

Oil Reconnection

Gas Relative Permeability

Pore Occupancy

Water Relative Permeability

Pore Occupancy

Experimental k rg Element et al. 2003

Comparison

Conclusions Water first invades the smaller throats at the dead-ends which does not change the gas relative permeability With snap-off process gas phase gets trapped There is a significant number of Double Displacement events Multiple Displacement is not required. However wettability conditions, spreading coefficients and saturation paths may change the situation

Future Work Debugging the code!!! Predicting the relative permeability behaviour of WAG process for different wettability conditions. Quantitative match with experimental data Come up with a new empirical three phase relative permeability model

Acknowledgments  Shell  Schlumberger  Statoil  BHP  BG  Saudi Aramco  Eni  Total  Japan National Oil Corporation (JNOC)  Department of Trade and Industry (DTI)  EPSRC We are thankful to the members of the Imperial College Consortium on Pore-Scale Modelling for their generous and continued support to our research: