DEEPWATER DRILLING AND PRODUCTION SYSTEMS OVERVIEW

Abstract

The petroleum industry is now involved in a highly significant exploration program to define the hydrocarbon potential of deepwater sedimentary basins. Within the last year, the ability to drill in waters deeper than 1300m has been demonstrated, and exploration plans for water depths down to 1600m have been announced. This paper reviews the industry's deepwater drilling experience and describes some of the unique technology required for a successful deepwater drilling venture. Drilling in over 1000m of water calls for more sophisticated, higher strength system components than are needed in shallower waters. Some of the differences between deepwater drilling procedures and more conventional shallow water techniques involve vessel carrying capacity, the use of a dynamic positioning system for staying on location, riser buoyancy materials, improved riser components and a multiplex electrohydraulic blowout preventer control system.

Progress has also been made in developing production systems for use in water depths greater than 300m. The guyed tower concept, a product of Exxon's developmental work, has been demonstrated to be a cost-effective alternative to fixed-bottom platforms. The caisson vessel, designed to accommodate both drilling and production activities and to minimize motion caused by rough sea conditions, is an attractive option for operations in deep water. In addition, experience with a prototype of Exxon's subsea production system has demonstrated that this system is also ready for commercial use.