Hydrodynamic Analysis of Flow Systems and Fault Seal Integrity in the North West Shelf of Australia

Abstract

The North West Shelf hydrodynamics pressure database, developed as part of the North West Shelf Hydrodynamics Project, currently contains 7,780 pressure data points and hundreds of stress, temperature and water salinity data. All data have been ranked using a newly developed quality-control system. Equivalent hydraulic head mapping (fluid potential energy analysis) to interpret fluid migration pathways, hydraulic barriers and conduits was shown to be a valid technique despite lateral and vertical fluid density variations. Pressureelevation analysis identified six major aquifer systems (hydrostratigraphic units) in the regional North West Shelf. On a regional scale, the general flow direction in the North West Shelf is from the basins’ depocentres towards the onshore and upwards to the shallower aquifer systems. Compaction-driven flow is the main driving force for fluid flow in the North West Shelf. Overpressured compartments in the Carnarvon Basin are leaking, not hydraulically isolated from the regional flow field, thus generating their own local flow system. In general, fluid flow within the hydrostratigraphic units is parallel to the trend of major fault systems, which act as barriers in the horizontal plane of the aquifer. However, local-scale hydrodynamic analysis has shown that faults can act as fluid conduits between hydrostratigraphic units providing vertical hydraulic communication (e.g. Mardie to Barrow aquifers). Case studies in the Harriet, Gorgon, Griffin, Goodwyn and Vulcan areas have shown that the migration paths can be very complex due to the hydraulic nature of the faults and the presence of overpressured compartments

Integrating hydrodynamic analysis of flow systems and induced-pressure decline at the Otway CO2 storage site to improve reservoir history matching

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Pressure and fluid dynamic characterisation of the Dutch subsurface

“…The hydrodynamic approaches involve the use of single-well and multi-well pressure-depth plots, regional overpressure maps and hydraulic head maps. Verweij (1993), Dahlberg (1995), Otto et al (2001), Bachu & Michael (2002) and Verweij et al (2011) provide an overview of hydrodynamic analysis techniques. Here we present pressure-depth plots, leak-off pressure-depth plots, and a selection of overpressure maps and cross-sections.…”

Multi-disciplinary approach to fault and top seal appraisal; Pyrenees–Macedon oil and gas fields, Exmouth Sub-basin, Australian Northwest Shelf

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