World-Wide Deepwater Exploration and Production: Past, Present and Future

摘要

Exploration and production in deepwater (>500m)rnhas expanded greatly during the past decade, withrnapproximately 58 BBOE discovered, more than half sincern1995. Despite this rapid emergence, deepwater remains anrnimmature frontier, accounting for less than 5% of the currentrnworld-wide total oil-equivalent resources. Only about 20% ofrnthe discovered deepwater resources are developed and lessrnthan 5% have been produced.rnThe global deep water exploration success rate wasrnabout 10% until 1985, but has since averaged approximatelyrn30%, driven by remarkable success in the Gulf of Mexico andrnWest Africa. Whereas the world-wide discovery of giants hasrnfallen off in recent decades, the discovery rate of deep waterrngiants is rapidly increasing.rnMost exploration activity has been concentratedrnwithin only three areas of the globe, with a majority of therndiscovered resources in the Gulf of Mexico, Brazil, and WestrnAfrica. Consequently, large portions of the world’s deepwaterrnmargins remain lightly explored. Deepwater gas explorationrnis extremely immature, reflecting current infrastructure andrneconomic limitations, but destined to become a majorrnfuture focus.rnMost of the currently most active deepwaterrnexploration frontiers and associated resources are locatedrnalong passive margins, downdip from productive Tertiaryrndelta systems, in depocenters confined by mobile substrate. Inrnsimplest terms, petroleum systems responsible for the majorityrnof the discovered resources can be classified as either early riftrn(lacustrine) or later passive margin (marine). Ninety percentrnof the resources are reservoired in turbidites, primarily ofrnCenozoic age. A key success factor is targeting "high kH"rnreservoirs, which have high flow rates and well ultimaternrecoveries. These commonly occur within ponded minibasinsrnassociated with mobile substrate, where stacked turbiditesrnresult in high net pay per area. Other key exploration successrnfactors have been seismic DHI’s, identification of stratigraphicrntraps, and improved reservoir architecture prediction. Leadingrncompanies are moving into non-DHI plays and other geologicrnsettings, including pre-Tertiary objectives and areas lackingrnmajor updip reserves.rnRecent trends suggest several themes for future deeprnwater exploration: 1) a continuation of established plays,rnwhich are still at an immature stage of drilling, 2) goingrnbeyond the established formula, to basins lacking updiprnproduction, unconfined basins, compressive margins, andrntargeting pre-Cenozoic, non-turbidite, and non-DHIrnobjectives, 3) increased gas exploration, as pipeline networksrnand liquefaction technology advance in conjunction withrnincreased demand, 4) going deeper, both ultra-deep water andrndeeper drilling depth, including subsalt, sub-detachment, andrnsub-volcanic targets, and 5) new business opportunities whichrnmay arise in areas currently not open due to governmentrnmonopolies, moratoriums, and international boundaryrndisputes. New frontiers with these characteristics are beingrnactively leased, but it remains to be seen whether therndeepwater play will continue to add reserves at the rate ofrnrecent years.