Two-stage construction of the Nogat gas pipeline from the northern part of the Dutch North Sea to the mainland is opening development opportunities.
A series of gas finds will be linked to the new pipeline. The level of development in this area should accelerate as presence of the pipeline encourages exploration along the route.
Dutch waters remain mostly a gas play. Gas production averages about 1.7 bcfd, while oil output has slipped below 50,000 b/d.
Development work continues to benefit from government policies ensuring that even the smallest reservoirs can be linked into the sector's extensive pipeline system.
The fiscal regime makes it feasible to develop fields with reserves less than 35 bcf. The Dutch distribution company Gasunie always buys the output to conserve production from huge Groningen onshore field.
Resulting conservation of Groningen reserves has enabled Gasunie to extend its valuable export contracts.
Elf Petroland plans a new development complex on Block K6 that will handle its K6A, C, D, and DN structures and provide for possible future discoveries within the tie-back range of the production system.
The project consists of a treatment and utilities platform linked to a wellhead/riser unit and two unmanned satellite platforms. The complex is being designed to handle as many as eight satellite platforms.
The main installation work will occur during 1991, with the balance extending into 1992.
Contracts have been awarded for topsides of the two central complex platforms. Jacket contracts are expected to be awarded shortly. All units will be installed next summer, and drilling is scheduled to begin in September 1991 with tieback of one well and spudding of another.
The two drilling platforms will be linked into the central complex by 3 mile, 10 in. and 3 in. lines. The first drilling platform will be installed in the fall of 1991, and the drilling program will begin after tie-back of an existing well.
On the second unmanned drilling platform, two exploration wells will be tied back, followed by spudding of the first of two horizontal wells.
Petroland said it is performing internal feasibility studies on finds in Blocks K4 and K5 but has no firm development plans.
Also on Petroland books is an unmanned wellhead and treatment platform on Block F15, along the Nogat route.
The jacket will be installed in summer 1991. The exploration well will be tied back, followed by two horizontal wells. Petroland said it will install topsides once the drilling program is complete.
NAM PROJECTS
NAM also is developing projects to link with Nogat. It has begun a two-phase development of L12 and L15 gas fields on the inshore section of the line.
In the first phase, NAM will install an integrated drilling and production platform, to start up in October 1992. The L12 reserves will be produced through an unmanned satellite platform.
The F3 area contains 425 bcf of gas and 30 million bbl of condensate. Outline plans from NAM call for two platforms to support production of 25,000 b/d of condensate and 130 MMcfd of gas.
Gas also has been found and developed in the environmentally sensitive area of inland waters between the Frisian Islands and the coast.
NAM has been awarded a production license for Ameland North Field, which lies on the North Sea side of Ameland Island.
NAM is producing gas from Ameland East field through an onshore production unit and an offshore platform. It exports the gas through a short link with the Noordgas-transport system.
Industry sources estimate Ameland North has 100 bcf of reserves and might be exploited with extended reach wells from the Ameland East offshore platform.
BUNTER DEVELOPMENTS
Farther south, Amoco is looking at two development options for five small gas discoveries made from the Bunter sandstone in the P quadrant.
The five finds may have reserves of 750 bcf of gas and would require a central processing platform, which could be installed close to Amoco's Rijn oil production facilities in P15a.
Each of the gas reservoirs would be developed with an unmanned satellite platform tied back to the central processing complex, which in turn would be linked with Rijn's liquids handling facilities and pipeline to shore.
The less favored alternative is to install drilling and processing facilities on the P18a prospect. This would be tied back to the four unmanned platforms. It would still need an outlet for liquids, although a separate drilling platform would not be needed.
Mobil Producing Holland expects to start up its P12 gas development this fall.
Last month the company installed jackets on the P12 southwest and central structures. The units usually will be unmanned.
The four-leg satellite units are linked by a 4.3 mile, 8 in. pipeline. The whole development will be tied back to Mobil's existing gas production facilities in P6 field by a 26 mile, 12 in. pipeline that was also laid this summer.
The two structures contain combined reserves of 110 bcf. Plateau production is expected to be 45 MMcfd, reserves life 9 years.
Mobil's P6 facilities are connected to the Noordgas-transport system to Uithuizen. Mobil acquired capacity in the line to serve its P6 field. Output averages only 80 MMcfd, leaving spare capacity for the P12 output.
An Ultramar unit looks set to develop the first Anglo-Dutch gas field. The company has completed appraisal of the Markham gas prospect on Dutch Block J6. Development plans are being drawn up, although the production license has not been granted.
Most of the estimated 400 bcf of reserves are in Dutch waters. Ultramar operates the U.K. blocks onto which the field extends. Production will be landed in Holland, probably starting in 1992.
DUTCH OIL
Netherlands produces 46,000-47,000 b/d of oil from the North Sea. Operators of the three production complexes are looking for ways to delay production declines.
A unit of Unocal, operator of the Q1 complex, moved the tripod tower from the Helder B structure in the Q1 production complex to small Haven field. Two horizontal wells were drilled into the 2 million bbl reservoir, adding 4,700 b/d to total production now averaging just under 15,000 b/d. That compares with 12,000-13,000 b/d in 1989.
Two horizontal wells were drilled into Amoco's Rijn field last year, but the overall decline has continued. The field is producing about 4,000 b/d, compared with 10,000 b/d at the beginning of last year.
Conoco Netherlands has also drilled more development wells on the Kotter/Logger complex, where output is holding up at 28,000 b/d.
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