An Automated Approach to Determining Regional Scale Hydrocarbon Loss/Preservation Due To Fault Reactivation. An Example from the Timor Sea

Christopher Peter Dyt, Julian Strand, Anthony Gartrell, and Laurent Langhi
CSIRO Petroleum, Perth, WA, Australia

Top seal breach due to fault reactivation represents a major risk to the preservation of trapped hydrocarbons. Based on comparisons between structural histories and the distribution of current and palaeo-oil accumulations, , Gartrell et al. (2005, 2006) proposed that the partitioning of post-rift strain between faults in relation to trap geometry was critical in determining oil preservation during Neogene fault reactivation in the Timor Sea. The majority of trap bounding faults in the region have been reactivated. However, the distribution of post-rift displacements is heterogeneous and depends heavily on rift-phase fault size, location and interaction with nearby faults. Preferential localisation of post-rift strain onto longer faults in the population led to partial protection of some fault-bound traps with favourable geometries, but promoted breaching of others.
We present here a new piece of software, designed to rapidly assess quantitative geometric relationships between faults on regional-scale maps and rank regions (risk mapping) based on the trap integrity model mentioned above. The software processes large volumes of data in a few minutes using a basic desktop machine.
A study of the Timor Sea, North West Shelf Australia, comprising the northern end of the Londonderry High & Nancar Trough, has been completed. Results have been cross referenced to known well data. The survey analysis also highlights new areas, for more detailed studies.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece