Abstract
Deformation bands may show permeabilities that are a few orders of magnitude lower than the surrounding host rocks and therefore have a negative impact on fluid flow in sandstone hydrocarbon reservoirs. Understanding the geometrical attributes of individual bands and their patterns is a critical step in quantifying their connectivity and interpreting how they may compartmentalise reservoirs in the subsurface. In order to gain insights into the shapes, cross-cutting relationships and connectivity of these structures, we developed 3D geometrical models (scaled to centimetres) of deformation bands and joining ladder structures, using a sliced small-scale rock sample from outcrops at Hopeman, Moray Firth (Scotland) and near Goblin Valley, Utah (USA). This 3D geometrical model is used for two-phase flow simulations (water-oil and gas-oil) in order to investigate the effect of deformation bands on time to water breakthrough, waterfront propagation and sweep efficiency. We also investigated capillary effects on flow. Flow simulation results show that the presence of deformation bands led to various time to water and gas breakthroughs, irregular shape of water and gas front propagation and various sweep efficiency for different flow-system. Furthermore, understanding the dynamic behaviour of flow through these structures can lead to better predictions of the influence of deformation bands on fluid flow in subsurface reservoirs.
Original language | English |
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Article number | 104215 |
Number of pages | 19 |
Journal | Journal of Structural Geology |
Volume | 141 |
Early online date | 17 Oct 2020 |
DOIs | |
Publication status | Published - 31 Dec 2020 |
Bibliographical note
AcknowledgementsWe thank Schlumberger Ltd. for access to the academic licenses for Petrel and Eclipse software. We also thank Midland Valley Ltd. for access to the academic license of Move. We thank the Institute of GeoEnergy Engineering at the Heriott Watt University for the Pore Scale Network Simulator. We extend our gratitude to Haakon Fossen for his revision of an early version of the manuscript. Thoughtful and constructive reviews by Atle Rotevatn and an anonymous referee have significantly improved the clarity of the manuscript. We are indebted to Martin Blunt from Imperial College London for his permission to use their labs for MicroCT scans. We thank Tim Wynn from TRACS International Ltd for his advice on assigning petrophysical values to the grid. We thank David Healy from University of Aberdeen for his thoughtful ideas and assistance in the field. We are grateful to Colin Taylor from University of Aberdeen for his assistance in the rock sample slicing.
Keywords
- deformation band
- Ladder
- X-Ray micro -CT
- Pore-scale simulation
- Flow simulation
- sandstone