Neotectonic Provinces of NW Borneo

Rosalind C. King, Richard Hillis, and Mark Tingay
Australian School of Petroleum, University of Adelaide, Adelaide, SA, Australia

Maximum horizontal stress (σH) orientations are considered to be parallel to absolute plate motion directions. However, across NW Borneo σH orientations are not parallel to the ESE Sundaland plate motion direction. Observations of borehole breakout from 86 petroleum wells over the Baram Delta-Deepwater Fold-Thrust Belt System, north Sabah and the Balingian area have been used to characterize five distinct neotectonic provinces; an extension province, a compression province, an inverted province, a North Sabah province and a Balingian province. The extension and compression province are situated on the outer shelf and slope to basin floor and are defined by active gravity driven deltaic tectonics. The extension province exhibits NE-SW striking, active normal faults reflecting a NE-SW σH orientation. The compression province exhibits NE-SW striking active thrusts, consistent with a NW-SE σH orientation. The inverted province is situated onshore to inner shelf. It is defined by inverted ancient deltaic normal faults and exhibits a NW-SE σH orientation. The North Sabah province is located on the slope to basin floor, offshore northern Sabah. It exhibits a N-S σH orientation, reflecting stress perturbations caused by a change in trend of the fold-thrust belt. The Balingian province is situated offshore Sarawak. It exhibits WNW-ESE σH orientations, closely reflecting the ESE plate motion direction. This poster illustrates five neotectonic provinces across NW Borneo; four of which exhibit σH orientations that are not primarily controlled by the ESE plate motion direction. Each of the five neotectonic provinces result in distinct implications for petroleum exploration and development in the area; such as, borehole stability, hydraulic fracture stimulation, seal integrity and fault reactivation.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas