Hydrodynamics in the Queensland Sector of the Cooper/Eromanga Basins: Identifying Non-Conventional Exploration Plays Using Water Pressure and Chemistry Data

摘要

Analysis of water chemistry and pressure data from thernQueensland sector of the Cooper and Eromanga Basinsrnindicates that two regional fluid flow systems are operatingrnwithin these basins. In the Eromanga Basin (Jurassic–rnCretaceous) a southwestward and descending open flowrnsystem is evident, driven by the topographically induced GreatrnArtesian Basin hydrodynamic regime. In the underlyingrnCooper Basin (Upper Carboniferous–Triassic) a closed systemrnis reflected by overpressuring and ascending flow out of eachrnof the major Permian troughs. Where the two systems interactrnand equilibrate, mixing of formation waters from Permian andrnJurassic reservoirs is apparent in water chemistry data andrnpotentiometric surface minima can be identified in verticalrnpressure profiles.rnThe water chemistry and pressure data have been used tornidentify hydraulic baffles within the Permian and Jurassicrnsequences. These barriers are likely to provide effective lateralrnor vertical seals and, once identified, can be targeted inrnregional mapping projects to identify potential stratigraphicrntraps. In addition to the potential exploration applications,rnregional hydrodynamic databases are also valuable inrnpetrophysical evaluations, by providing estimates of waterrnresistivity in areas with poor well control, and for estimatingrnfield limits when the only available pressure data are fromrnhydrocarbon columns within crestal wells.