Abstract

The Elang-1 oil discovery in the Timor Gap Zone of Cooperation (ZOC) has established a new oil province in the eastern Timor Sea and helped bridge the exploration gap in the Northern Bonaparte Basin. The discovery well, completed in February 1994, recorded a flow of 5800 BOPD from marine sandstone of the Late Jurassic Montara beds. The oil is a light 56° API), undersaturated oil with a GOR of approximately 550 SCF/STB as measured in the discovery well. Elang-1 was the first well drilled by the ZOCA 91–12 Joint Venture and only the fifth well in the ZOC since exploration of this frontier area resumed in 1992.

The Elang Prospect, initially mapped by Petroz in the late 1970s on the basis of regional seismic data, was detailed by the 1992 Walet Seismic Survey. The prospect is the main crestal culmination on the Elang Trend, a prominent structural high to the north of the Flamingo High that was established during continental breakup in the Late Jurassic. The Elang Trend is bounded to the south by a series of en-echelon normal faults and connecting relay ramps and comprises a number of separate horst and tilted fault blocks.

Elang-1 was a near crestal test of the Elang Prospect and intersected a 76.5 m gross oil column below 3006.5 m RT. Good quality reservoir sandstone in six discrete bodies were intersected within the Montara beds. Core measured porosity and permeability range up to 17 percent and 2.2 Darcies within the oil column.

Subsequent to the Elang discovery, the Joint Venture recorded a 402 sq km 3D survey and drilled an appraisal well, Elang-2. Elang-2 established the lateral continuity of the Montara beds reservoirs and achieved flow rates of 6080 BOPD and 7500 BOPD. Further exploration has been rewarded with discoveries at Kakatua-1 and Elang West-1 in ZOCA 91–12, Bayu-1 in ZOCA 91–13 and Laminaria-1 in AC/P8 (adjacent to the ZOC).