Abstract

Timor island, situated in the Banda arc-continent collision zone, is the location of numerous oil and gas seeps, and contains high-quality hydrocarbon source rocks. Despite this, the island is widely considered to have only moderate petroleum potential due to its well known structural complexity. It is suggested here, however, that this complexity is limited to shallow structural levels, and below this a simpler structural style predominates. In particular, the Kolbano area of southern West Timor is interpreted to be underlain by a very large and structurally simple inversion anticline, capable of hosting a giant hydrocarbon accumulation. The Banli-1 exploration well only penetrated the flank of this structure, perhaps 300-500m below the prospective crest. Banli-1 was drilled on a gravity high, which corresponds to the footwall basement block of the inversion structure, not to the crest of the hangingwall anticline. Similar if smaller structures are likely to occur elsewhere both onshore in West Timor and offshore to the south in the northern slope of the Timor Trough.