Abstract

Kurau consists of two separate anticlinal low relief structures, 'BG' and 'AC', located on the eastern margin of the Bengkalis Trough. The traps were formed by drape over structures formed in the late Oligocene. These structures, cored by basement and Pematang Group rocks, remained largely unaffected by Late Miocene to Pliocene tectonism. This later tectonism produced many relatively high-relief structures which were the focus for early exploration in the area.

Both low-relief Kurau structures contain stacked oil pools and, at the level of the principal Early Miocene Lower Sihapas Formation reservoirs, have mapped seismic TWT closures of 12 to 13 milliseconds (Approx. 70-80 feet). Kurau contains in excess of 150 MMBbls of oil in-place and is currently the largest field in the PSC area. It was discovered late in the exploration history of the area, some 16 years after exploration commenced and six years after the first commercial discovery, due to the relatively subtle nature of the trap.

The successful phase of exploration accelerated by the discovery of Kurau forms a discrete episode of activity in the exploration history of the PSC area. The problems successfully addressed at Kurau, associated with acquiring reliable seismic data, producing accurate time structure maps, identifying oil sands and fluid contacts and understanding the complex Lower Sihapas Formation reservoir systems, were instrumental in the successful exploitation of a number of similar but smaller discoveries.