Maersk Giant, seen here in drydock at Verolme Botlek's yard in Rotterdam, was used by Amerada Hess (Denmark) to drill the Rigs-1 well.Improved recovery schemes at the Dan and Gorm Fields will nearly double oil and condensate production off Denmark over the next four years. Thereafter, the Danish Energy Agency (DEA) foresees a steep decline to 2010, but the current new wave of exploration could force a re-think.
Latest DEA figures for the country's nine producing fields show a combined output of 6.3 bcm of gas last year (unchanged from 1993). Oil and condensate, however, jumped 10% to 10.7 million cu meters, and should continue climbing to a peak of 14.3 million cu meters in 1999. That outlook is considerably more positive than the corresponding DEA forecast last year.
A major contributor will be the Dan Field. The Dansk Undergrunds Consortium submitted a further development plan this February calling for the water injection (secondary recovery) project to be expanded to include the whole field. This would entail substantial expansion of the production facilities, including a new wellhead and processing platform.
Recovery plans
Dan is one of Denmark's three offshore processing centers. Production started here in 1972, with development of the field continuing in phases through the '70s. In 1982 a new 24-well production center was implemented, Dan F, followed by phased primary recovery and also secondary recovery in parts of the field through water injection: between 1989 and 1994 6.65mcm of water was injected into the field.
Now the DUC wants to extend the secondary recovery technique to the field's southeast flank and to the area under the Dan gascap. It would involve drilling up to 42 new wells on top of the 78 in service at the end of last year. Capacity of water injection facilities would be doubled to 300,000b/d of water, leading to oil production from Dan increasing to around 90,000b/d at the turn of the century.
Dan has two satellite oilfields, Regnar and Kraka, with the latter producing through six horizontal wells. Performance of these wells has raised hopes for future recovery from the field: a PDO for a second-phase development will be submitted in the next year.
Twenty seven kilometers northwest of Dan is the Gorm oilfield with its three satellites Skjold, Rolf and Dagmar. Gorm, which came onstream in 1981, comprises two reservoir blocks divided by a major fault: in 1992 the Danish Energy Ministry approved a scheme to improve oil recovery through water injection, initially in the western reservoir block.
Here oil is being recovered from mid-flank areas of the reservoir, with simultaneous water injection in the flanks. Later on, recovery tactics will shift to the structure's crest: a reservoir study of the western block by Maersk last year has upped estimates of the potential recoverable.
Gorm's eastern reservoir development involves water injection under the oil zone, simultaneously increasing the number of production wells.
Most of the producer and water injector wells have been drilled (horizontal drilling has been on a much larger scale than originally planned). This year a third deck is likely to be installed on the Gorm F platform to handle extended processing facilities.
The DEA has also approved plans for a fourth deck, wellhead compression facilities and a new test separator for this platform, likely to be completed in 1997. The wellhead compression is crucial to recovery plans not just on Gorm, but also Skjold and Rolf: targeted oil production increase for the three fields is around 2mcm up to 2012.
Denmark's other main production center, the Tyra complex, is being expanded to increase gas supplies to Dansk Naturgas from 1997 and to tie in new satellite fields. Two of these, Svend and Roar, should start producing next year through Star-type unmanned wellhead platforms.
Over the following two years, two gas accumulations 80 km north of Tyra will be brought onstream. First will be Harald West, via a four-leg processing and wellhead platform bridge linked to a Star platform, both controlled remotely from Tyra. Then in 1998, Harald East should start flowing from two wells into another STAR wellhead platform specially adapted to the field's deeper waters.
Other small satellites expected to hook into Tyra are Adda, Elly and Tyra South East. Gert and Lulita are fields elsewhere in the Danish sector with development plans pending (the latter might host Denmark's first floater). Danish production could rise further if Amerada Hess progresses beyond appraisal of the South Arne discovery.
But these are just the known fields. The Energy Ministry has been anxious to rekindle exploration off Denmark, especially following the massing of rigs to the new Atlantic province. Recent measures seem to have worked.
Relaxing of financial terms under Denmark's 4th licensing round led to nine new licences being awarded this year in or east of the Danish Central Graben. Award winners include Mobil, a first-time licensee in this area.
Combined work programs for the nine licences include six obligation wells and eight conditional wells, along with the obligatory seismic surveys. Up to DKr1,350 million of exploration spending could ensue.
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