Tuesday, March 19, 1:00pm

Mr. Aaron Cummings

PhD Candidate, NCPGG, The University of Adelaide

2D Structural Restoration and Thermal Maturation Modelling of the Bass Basin: Implications for Hydrocarbon Migration  


Two regional seismic sections have been interpreted across structurally distinct regions of the Bass Basin. Both sections have been depth converted, structurally balanced, decompacted, and restored using the structural restoration software 2DMove. Restoration has been undertaken in order to constrain the timing of regional tectonic events responsible for basin structuring and to reconstruct the configuration of the basin during the main periods of hydrocarbon generation and migration. The central Bass Basin has undergone approximately 12 % upper crustal extension since the early Cretaceous, whereas the Durroon Sub-basin has undergone approximately 22 % upper crustal extension. This highlights the difference in the structural evolution between the two regions and the increasing influence of Late Cretaceous Tasman Rifting towards the east of the Bass Basin.

Thermal history and maturation modelling has been carried out on a number of wells throughout the basin using the 1D BasinMod program. Geothermal gradients range between 30 to 65 degrees C/km, with significant lateral variation across the basin. Comparison between measured vitrinite reflectance and calculated maturity from default thermal history models indicates that the Upper Cretaceous to Recent sequence is experiencing maximum temperatures now. Subsidence/maturation modelling allows us to constrain relative amounts of subsidence across the basin as well as delineating the timing of hydrocarbon generation and migration.

The success of future exploration within the Bass Basin depends on a greater understanding of the structural and thermal evolution of the basin and its relationship to the timing of hydrocarbon generation and migration.

Biography of the Speaker

Aaron completed his BSc majoring in Earth Sciences from the University of Queensland in 1997, and his Honours 1998. His honours research was concerned with the Devonian to Triassic evolution of the western region of the Yarrol Province of the New England Fold Belt. He started his PhD at the NCPGG in 2000 investigating the structural history and hydrocarbon migration in the Bass Basin. Aaron worked for a number of years with Placer Dome Exploration, and has also worked with Geoconsult and the Queensland Museum.