Transient fluid flow in the Timor Sea, Australia: implications for prediction of fault seal integrity

Abstract

A variety of geochemical techniques have been used to identify vertical remigration of oil and saline formation water from Mesozoic hydrocarbon traps in the Timor Sea, Northern Australia. This transient fluid flow event is thought to have been initiated by the Mio-Pliocene fault reactivation and has a major impact on the seal integrity of fault dependant hydrocarbon traps. Significant thermal anomalies appear to accompany brine flow and together with the highly saline nature of the fluids and absence of a shallow salt source suggest that these originate from deeply buried Palaeozoic evaporites. Numerical simulations have been utilised to test this hypothesis, and in combination with the empirical observations seek to provide an enhanced prediction of fault seal integrity for future exploration.