AUSTRALIAN OFFSHORE DRILLING: PAST, PRESENT AND FUTURE

Abstract

The Australian offshore drilling industry is now ten years old. In late 1964 the Global Marine drill-ship "Glomar III" spudded Esso's Gippsland Shelf No. 1 (later re-named Barra-conta-1); the discovery well of the Barracouta gas field. Fourteen other mobile offshore rigs have drilled wells in Australian waters, including one jack-up, four semi-submersibles and two drill-barges. Five production platforms have been built and now supply Australia with a large proportion of her oil requirements.

Water depths have ranged from 8 m (Ripple Shoals No. 1) to 388 metres (East Mermaid No. 1) and distances offshore from the mainland from 5 km (Golden Beach No. 1/1A) to 400 km (Troubadour No. 1). Wells have been drilled to depths of over 4,500 metres.

Several new techniques have been introduced including turret mooring (Discoverer II), foam drilling (Glomar Tasman) and dynamic positioning (Sedco 445). New drilling vessels under construction in Australia will provide additional offshore drilling capacity.

For the future we can expect to see larger drill-ships and semi-submersibles which will be able to continue drilling operations in adverse weather conditions. Dynamic positioning and improved conventional anchoring systems will enable the deeper waters to be explored. New equipment and techniques will probably include buoyant marine risers, sub-sea mud discharge pumps and electro-hydraulic preventer actuated systems.