Project Profile
Value: US$6.96 million
Location: North West Varanus Island
Reserves: 4.1 mb of condensate
Production: 65 mmcfd
Depth: 30 Metres
Exploration start-up:- 1995
Production start-up: -01.07. 2007
Wonnich Field lies in Licence TL / 8 off the Western Australian coast, approximately 25km northwest of Varanus Island. The field contains up to 214 petajoules of gas at a 50% probability level and 4.1 million barrels of condensate. The project was executed by a joint venture formed by Apache Northwest Pty Ltd, Kufpec Australia and Tap (Harriet) Pty. The value of the project is estimated to US$6.96 million. The Wonnich 1 discovery well was drilled in August 1995. In order to delineate the reservoir, Apache carried out back-to-back drilling of the Wonnich-2 and 3 appraisal wells in August 1997.
The drilling over the first well, Wonnich Deep-1, was carried out in March 2007. The well was drilled using the Wonnich platform. While drilling, the well penetrated the upper Jurassic Dupy Sandstone interval. The drilling led to the discovery of additional gas in two zones during the first quarter of 2007, however, production from the platform and gas production from W-1 well was affected because of safety requirements. The drilling of the well was held temporarily because of cyclone evacuations and mechanical problems. Wonnich Deep-1 well hit a 60-metre section in relatively poorly developed Upper Jurassic Dupuy sandstones. After initial clean-up the well was flowing at a stabilised rate of 50 MMcfd with current flow rates of about 65 MMcfd. With the penetration of flag formation, the Wonnich Deep-1H well came onstream in July 2007.
Wonnich is developed by an unmanned platform, tied back to production facilities at Varanus Island, 31km away, from which the platform is remotely operated. The three-leg lattice platform stands in 30m of water. The platform consists of two decks. Inside it has the necessary facilities for one producing well and the additional capacity for three spare slots for the potential tie-in of future wells. There are two production manifolds, as well as provision for a third riser. The top of the structure stands 55m above the seabed. The topside is 115t, while the lower and upper substructures are 335t. The main piles and insert piles weigh 195t, giving a total weight of 645t. The platform and pipeline for Wonnich are designed to produce up to 120 terajoules (tj) per day. The conceptual engineering studies for the field development were carried out by Brown & Root. The fabrication contract was given to BARBOS, a joint venture between Brown & Root and BOS Australia.
Operators:
Apache Northwest Pty: 68.5% interest
Tap (Harriet) Pty (subsidiary of Tap Oil): 12.2% interest
Kufpec Australia Pty Ltd: 19.3% interest
Contractors:
Brown & Root: Carried out conceptual engineering studies for the field development.
BARBOS (Joint venture between Brown & Root and BOS Australia): The fabrication contract.
Subcontractors: