Phillips Petroleum Co. U.K. Ltd. has its eyes on possible satellite hookups to its Judy/Joanne field development project under way in the U.K. North Sea.
Oil and gas production is due by yearend from the fields, under development using a conventional steel platform in Block 30/7a Judy field with subsea satellite development of Joanne on the same block.
Elsewhere off Northwest Europe:
- Chevron U.K. Ltd. is wrapping up plans for a development program in the southern portion of Alba oil field in the U.K. North Sea. Chevron's original intent was to tap this part of the field with a second platform, but advances in extended reach drilling allowed a change of plan.
- Conoco Norway Inc. completed installation of tethers for its Heidrun field tension leg platform ahead of its June 1 schedule. The operation had been delayed by sinking of one of the tethers during tow-out to the Norwegian Sea (OGJ, May 29, p. 16). Conoco also took delivery of the world's first titanium drilling riser. It is to be installed this summer in Block 6507/7 Heidrun field off mid-Norway.
- BP Exploration Operating Co. Ltd. let contract to Geco-Prakla, Woking, U.K., to design and install a permanent seismic data acquisition unit in Foinaven field west of Britain's Shetland Islands. Purpose of the seabed equipment is to keep a check on reservoir performance. It is the only field marked for development in the West of Shetland frontier.
JUDY/JOANNE OIL AND GAS
The Judy platform is designed to process as much as 95,000 b/d of liquids and 450 MMcfd of gas. There is spare capacity to allow processing of oil and gas from other fields.
Combined reserves in Judy and Joanne fields amount to an estimated 97 million bbl of liquids and 796 bcf of gas. Development cost is pegged at 767 million ($1.15 billion).
Oil production is expected to begin at about 90,000 b/d, falling away to yield a first year average of 55,000-60,000 b/d. Gas production is expected to be at a plateau of 260 MMcfd for 8 years, followed by a decline.
Liquids will move through a new 51.6 km, 24 in. pipeline to join the existing Norpipe line, which transports oil from Phillips' Ekofisk complex in the Norwegian North Sea to Teesside, England.
Gas will be sent from Judy platform through a new 70.4 km, 20 in. pipeline to join the existing Central Area Transmission System (CATS) pipeline to Teesside.
JUDY/JOANNE INFRASTRUCTURE
Tow-out for the 9,200 metric ton Judy platform deck is due June 13 from AMEC plc's fabrication yard at Wallsend, U.K.
Load-out of the 3,600 metric ton gas treatment module was due late last month at the Trafalgar House Offshore Ltd. yard at Methil, Scotland. This module is scheduled for tow-out to the field June 18.
Trafalgar House also is completing Judy's flare boom, which was to be loaded out June 10 for tow-out June 20.
The 7,200 metric ton Judy jacket was towed from Sicily, where it was built by Consorzio Italoffshore. Installation was scheduled using the Micoperi 7000 heavy lift vessel operated by Saipem SPA, Milan.
Fourteen tubular steel piles, each weighing 580 metric tons, have been built by Lewis Offshore Ltd. at its Stornoway yard in Britain's Outer Hebrides Islands. Tow-out was scheduled late last month.
Joanne's subsea manifold was built by SLP Engineering Ltd. at its Teesside yard. It is to be installed early this month.
Tom Paulson, project manager, said drilling of production wells is almost complete. All 12 wells for Judy's early development have been drilled through a template installed last year.
Five wells for Joanne development have been drilled. By late May, Santa Fe's Magellan jack up rig was running completion on the last of the Joanne wells and is expected to finish drilling by July 24. Once the platform is installed, Magellan's rig will skid onto the Judy platform to tie back Joanne wells.
The Safe Britannia accommodation vessel is due in the field July 1 for a 6 month stay.
Allseas Marine Contractors AS of Chatel-St. Denis, Switzerland, last year used the Lorelay pipelay barge to install the gas export pipeline from Judy platform to CATS.
Also last year, Allseas installed a Y-piece in Norpipe and the oil export line from Judy. Two more Y-pieces are to be installed in the oil pipeline to allow third party transportation through Judy's infrastructure.
POSSIBLE SATELLITES
Phillips plans to use spare platform capacity to take further production from its own prospects in the area and handle third party production.
A Phillips spokesman said the company has mapped a number of prospects in the Judy area, mainly in Block 30/13 to the south, where Jessica, Josephine, and Jacqui prospects are the largest.
Paulson said one reservoir close to Judy platform, Jocelyn, was tested with a well last December, after a Judy development well proved to be a dry hole.
The Jocelyn well was said to have added at least 30 million bbl of oil equivalent to reserves and placed Judy/Joanne reserves proving plans back on track. Jocelyn will be tied back to Judy platform ready for field start-up.
Phillips plans to bring one Quadrant 30 prospect to development approval stage by the end of the year.
Jacqui is most likely to be put forward. The discovery well flowed 7,000 b/d of oil and condensate, but a 3D seismic survey showed it to be a small reservoir.
Phillips has tendered for drilling of one firm well plus one optional well in Jacqui in the third or fourth quarter.
Phillips also has taken over from Ranger Oil (U.K.) Ltd. as operator of Block 30/2c. This block holds jade prospect, where an obligation well remains to be drilled.
The optional well for Jacqui might be transferred to the Jade prospect, on which license partners agreed in late last month to drill a well this year.
Phillips' discoveries in Judy vicinity are Julia, Joy, Jocelyn, Jacqui, and Josephine. Exploration prospects are Jade, Jane, Joyce, Jenny, and Jessica.
Phillips said these discoveries and prospects, thought to be small, most likely will be developed with a network of subsea tiebacks to Judy They lie within 15 miles of Judy
Phillips is holding talks with Shell U.K. Exploration & Production about diverting oil production from Fulmar field through the Judy oil export line to join Norpipe. Fulmar oil is offloaded into tankers at present.
Two Y-pieces will be installed in the Judy oil export line, one this June and one later near the platform, to allow third party access to the line.
Phillips said Fulmar oil discussions could be finished soon, and exports through the Judy pipeline may begin next year.
Partners in the Judy/Joanne development are operator Phillips 36.5%; Agip (U.K.) Ltd. 33%; and British Gas Exploration & Production Ltd. 30.5%.
ALBA PROJECT
Chevron's drilling in the southern part of the Alba reservoir is to begin from the field's northern platform late this year or early next year.
Details of the drilling program have yet to be agreed with field partners and U.K. Department of Trade & Industry However, a Chevron official said "lots of development drilling needs to be done."
Alba went on stream early in 1994, using a steel platform and oil storage tanker with offshore loading of oil for export (OGJ, Jan. 31, 1994, p. 46).
Chevron plans to shut down the field this summer for routine maintenance. The platform's rig will be modified during that time.
First oil from southern reservoir wells is due early in 1996. Later in the year, extra processing equipment retrofitted to the platform will handle increased oil volumes.
Alba's current production is 75,000 b/d of oil. Production from the southern part of the reservoir will boost field flow to 100,000 b/d.
There will be no modifications to the storage tanker, but shuttle tanker visits for offloading will be increased from every 6-7 days at present to every 5 days.
The two phase original plan for development of Alba was a result of the field's Eocene heavy oil production from unconsolidated sands. The company wanted early experience of the reservoir's performance to judge further development requirements.
Besides avoiding the cost of a second platform, Chevron hopes to avoid installation of a subsea manifold in the southern part of the field.
A subsea manifold has been proposed to allow water injection into the southern area of the field, but Chevron's engineers now believe the northern platform can provide much of the water injection requirement.
HEIDRUN INSTALLATION
In early May Conoco reported the second of 16 tethers to be installed in Heidrun field had to be laid on the seabed after buoys at either end broke their straps (OGJ, May 15, Newsletter).
The Norwegian Contractors unit of Aker AS, Oslo, completed installation of the remaining 270 m tethers, along with one spare tether, before recovery of the sunken tether.
A Norwegian Contractors official said the sunken tether was recovered and towed back to the Gullvika yard where it was made. Although the tether shows no apparent signs of damage, Conoco will carry out tests.
The official said the lost tether was ditched in 240 m of water. Recovery involved the Pelikan service vessel and two anchor handling tugs, which were still under charter after the tether installation program.
Remotely operated vehicles (ROVs) were deployed from Pelikan to attach cables to the sunken tether. The cables were taken up by the tugs, which raised the tether under slight tension.
The tether was then towed inshore, where winches on the tugs lifted the ends of the tether into buoys. The tether was then towed back onshore.
Norwegian Contractors' next job in Heidrun will be tow-out of the platform topsides from Stavanger starting June 26.
TITANIUM RISER
Conoco plans a series of inshore trials on the 350 m long titanium riser before connecting it to the Heidrun platform in late summer, ready to begin development drilling around October.
The riser will be assembled from 24 standard joints, each 14.685 m long, with an internal diameter of 558.8 mm and a 25 mm W.T.
The assembly will be attached by a 14.724 rn long, tapered stress joint at the wellhead and a 14.685 mm long centralizer joint at the topsides.
Total weight of the riser and joints is 110 metric tons. Titanium was chosen to afford savings in riser weight for a given strength.
"Titanium is normally used in the aerospace industry," said Carl Sauer, platform well systems group supervising engineer for Heidrun.
"Use of this material reduced the effective weight of the risers by 70% compared with steel because titanium is 50% of the weight of steel and 30% stronger."
Sauer said the 22 in. I.D. makes this the largest bore drilling riser to date, and the riser joints are the longest titanium extrusions made.
Hunting Oilfield Services, Aberdeen, was engineering, procurement and construction contractor for the riser assemblies. Riser units were made in the U.S. and shipped to Aberdeen for stack-up and running tests.
Conoco plans to build Heidrun production to 200,000 b/d by yearend. The Transocean 8 semisubmersible rig has drilled 16 wells in the field to allow first production in August.
The rig, currently completing water injection wells, will tie back production wells to the Heidrun TLP after topsides are installed in late June.
FOINAVEN SEISMIC DATA
BP said its Foinaven field project will be the world's first use of permanent seismic equipment in a deepwater field. Foinaven water depth averages 480 m, while the technology previously has been used in less than 100 m.
Permanent sensors will allow time lapse 3D data acquisition at yearly intervals to provide a history of reservoir fluids depletion.
About 30 km of cable with built-in sensors will be laid across the reservoir this summer. A conventional 3D towed streamer survey will yield reference data.
The seabed sensors will expand on information obtained from the conventional survey, while the data will afford better reservoir management and increased production. The Henry Goodrich semisubmersible rig is drilling Foinaven development wells in Block 204/24a. Fourteen producers, seven water injectors, and two gas injectors are being drilled in two centers.
Four production wells are to be completed prior to start of production in first quarter 1996. Field development is 45% complete.
A turret for the Petrojarl IV production ship, which will be used for early depletion of Foinaven, was to be finished by the end of last month.
The turret and a storage tank will form the center section of the vessel, for which the bow and stem will be two halves of an existing submarine carrier.
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