--> Abstract: Physical Modeling of Primary Stratigraphic and Structural Controls on the Evolution of the Papuan Fold and Thrust Belt, Papua New Guinea, with Implications for Hydrocarbon Exploration, by Katie Lucas and John M. Dixon; #90039 (2005)

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Physical Modeling of Primary Stratigraphic and Structural Controls on the Evolution of the Papuan Fold and Thrust Belt, Papua New Guinea, with Implications for Hydrocarbon Exploration

Katie Lucas and John M. Dixon
Queen's University, Kingston, ON

Physical analog modelling by the centrifuge technique (at a scale of 1 mm = 1 km) has been used to investigate the structural evolution of the Papuan Fold Belt (PFB). Models are constructed of plasticine modelling clay and silicone putty, mechanical analogs of competent and incompetent rocks such as limestone/sandstone and shale, respectively, which are interlayered to assemble model units that represent the major mechanical units within the PFB (from top to bottom, the Darai limestone, Ieru shale, Toro sandstone (reservoir) and Imburu shale). Facies changes, syn-depositional faults and primary basement structures are built into the models to investigate how these factors control folding, thrusting and styles of hydrocarbon traps within the PFB.

Models with intact, plane-layered strata demonstrate that the strength and thickness of the lower décollement horizon (Imburu shale), combined with along-strike variations in mechanical stratigraphy, exert the greatest control on deformational patterns. Models with simulated syn-depositional extensional faults show that reactivation can occur early during deformation of the PFB, locally absorbing the majority of the shortening and controlling the location of fold- versus thrust-dominated structures. Modelling of inversion of extensional basement faults demonstrates early reactivation of the faults in a thick-skinned setting. Reactivated faults develop large basement-cored anticlines that are older than other contractional structures and accommodate much of the initial shortening.

The models can be applied to specific structural domains of the PFB to improve understanding of subsurface structures in order to enhance present reserves, and may aid exploration of new fields.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005