U.K. OFFSHORE WORK HITS RECORD IN '91

Oil and gas development activity off the U.K. reached record levels in 1991.

The number of producing oil and gas fields surpassed 100 for the first time last year, the U.K. Energy Ministry's annual Brown Book shows.

With additions to oil and gas reserves topping production in 1991 and near record levels of equipment and supplies on order for projects, prospects look good for continued development, said Energy Minister Tim Eggar.

Exploration budgets, however, are starting to falter (OGJ, Apr. 20, p. 25).

The Energy Ministry, now part of the U.K. Department of Trade and Industry, has replaced the Department of Energy, recently dissolved by the government, which previously published the annual Brown Book.

Meantime, U.K. North Sea operators have marked progress in 1992 on a number of development projects:

BP Exploration let contract to a combine of Technip Geoproduction and McDermott Engineering (Europe) Ltd. for design engineering for facilities planned for Forth oil field.
BP started production from Donan oil field with its Seillean monohull oil production vessel.
Conoco (U.K.) Ltd. installed a subsea production manifold in Lyell oil field.
Rockwater Ltd., Aberdeen, soon will install what it believes to be the largest subsea pipeline bundle. Site will be in the Piper/Saltire field complex for the Elf Enterprise Caledonia Ltd. group.
ARCO British Ltd. let two detailed design engineering contracts to a unit of Asea Brown Boveri for work related to Orwell gas field subsea development, which is expected to set a U.K. record for a remote subsea development.
Ranger Oil (U.K.) Ltd. drilled an apparent salt diapir oil discovery on a block near two recent oil strikes that flowed as much as 14,455 b/d of oil.
Amerada Hess Ltd. drilled a sizable discovery well in the Central U.K. North Sea.
BP, Conoco, and Phillips Petroleum Co. U.K. Ltd. each tested high flowing appraisal wells in the Central North Sea.
BP hired a floating accommodation unit from Bibby Line Group Ltd., Liverpool, to house workers during a maintenance program at Sullom Voe marine terminal on Shetland Island. The Bibby Progress flotel was built in Poland and can handle 300 personnel.

1991 DRILLING RESULTS

U.K. offshore operators announced 15 significant discoveries in 1991, and the number of fields on production advanced in 1992 beyond the record level last year.

At the same time, those operators have achieved record levels of capital investment. The U.K. share of available orders at 4.734 billion is only 50 million short of the record.

In 1991 U.K. offshore operators spudded a total of 186 wildcats and appraisal wells, the third highest level since exploration began in 1964. Of the 15 discoveries disclosed last year, five were spudded near yearend 1990 and tested in 1991.

1991 LICENSING RESULTS

The U.K. government granted 74 licenses covering 107 blocks in the 12th licensing round last year.

Separately, a frontier licensing netted six awards covering 66 blocks.

In onshore licensing, 39 companies submitted 41 applications, resulting in the award of 40 exploration licenses in the fourth onshore licensing round. New regulations governing onshore petroleum production took effect May 9, 1991.

The fifth onshore licensing round was announced Nov. 25, 1991.

Eggar expects the 14th offshore licensing round to attract strong interest.

RESERVES, PRODUCTION

With U.K. cumulative oil production through yearend 1991 at 10.695 billion bbl, remaining reserves are estimated at 4.05-14.3 billion bbl, up from a previous estimate of 3.9-13.2 billion bbl.

With cumulative gas production through yearend 1991 at a net 28.14 tcf, total remaining gas reserves are pegged at 18.9-63.2 tcf, up from a previous estimate of 19-62.3 tcf.

Estimated undiscovered potential reserves are estimated at 3.94-24.8 billion bbl of oil and 9.1-67 tcf of gas vs. last year's estimate of 3.65-22.8 billion bbl and 9.8-44.2 tcf.

The government approved 17 oil and condensate development and one pipeline project in 1991. In the first 2 months of 1992, five development plans were approved and another 14 were under study. At Yearend 1991, 25 fields were under development.

There were 46 offshore and 19 onshore oil fields producing at yearend 1991. That includes one offshore field and five onshore fields that started up last year. U.K. oil production reached 1.826 million b/d in 1991, down from the year before because of shutdowns of process facilities and pipelines to install emergency shutdown valves (ESVs) and conduct other safety related work offshore.

At yearend 1991, one onshore and 34 offshore gas fields were producing. One offshore gas field started up in 1991. U.K. gas production was 5.293 bcfd in 1991.

FINANCIALS

Proceeds from the sale of U.K. offshore oil production totaled 8 billion in 1991. Average oil and natural gas liquids price was 86/metric ton (11.78/bbl) in 1991, down from 90/ton (12.33/bbl) in 1990,

Proceeds from gas sales rose to 2.8 billion in 1991 from 2.4 billion in 1990.

Government's take, including taxes and royalties, from oil and gas in fiscal 1991-92 is tentatively estimated at Fl billion, compared with 2.5 billion in fiscal 1990-91. The government cites lower oil prices and increased investment.

Gross capital investment in U.K. oil and gas exploration and production in 1991 approached 5.1 billion in 1991, up about 41% from the 1990 level.

Offshore operators' total order book reached 6.1 billion in 1991, with U.K. suppliers accounting for 78% of total orders.

FORTH WORK

Operator BP plans to submit a development plan for Forth field to the U.K. government by yearend on behalf of itself 70% and partners Repsol SA 25% and Ranger 5%, provided company approvals are in hand. Production is to begin in mid-1996.

Discussions with a group of companies led by Kerr McGee Corp. with interests in nearby Gryphon field concerning joint development of the two fields are in a final phase to continue through the second quarter.

The Forth group is considering Technip's TPG 500 jack up for use as a drilling and production platform. The unit likely will use a concrete base to serve as foundation and storage facility.

Development is expected to involve fewer than 10 horizontal wells drilled from the platform to tap Forth's two major pools. That's a change from the original plan, which called for subsea wells for the main pool, and stems from experience gained in drilling a horizontal appraisal well in Forth last summer.

Forth lies in Block 9/23b about 220 miles northeast of Aberdeen and 5 miles south of Gryphon.

Forth field contains about 165 million bbl of oil and 180 bcf of gas. Satellite structures on the block are believed to hold another 15-40 million bbl. GOR is 275:1.

Production is expected to plateau at about 60,000 b/d of 21 gravity oil within 6 months of start-up. The field was discovered in 1987 in 355 of water.

DONAN START-UP

Donan, the second field developed using BP's Swops system, lies about 220 km northeast of Aberdeen on Block 15/20a.

The 100% BP owned field holds about 25 million bbl of oil reserves.

Flow started Apr. 28 at 2,000 b/d and was scheduled to climb to more than 15,000 b/d by mid-May. To prepare the suspended discovery and appraisal wells for production, BP used the Sea Explorer semisubmersible to install Swops subsea wellheads, interconnecting flowspool and control equipment prior to Seillean's arrival Apr. 27.

Initial production will be limited to 1 year while reservoir performance is assessed to determine if Seillean is the best choice for long term development.

Seillean previously operated in BP's Cyrus field in Central North Sea Block 16/28, where production will be suspended during Seillean's deployment to Donan. Although Seillean may return to Cyrus later, BP is considering other development options for the field.

Donan was discovered in May 1987 with the 15/20a-4 exploratory well.

Harland & Wolff built Seillean for BP as a flexible oil production, storage, and transportation system designed for small field development. The vessel, dynamically positioned above the well during production, can store 300,000 bbl of oil.

CONOCO LYELL

Conoco used the DB102 crane barge to install Lyell field's 500 metric ton manifold in 479 ft of water in on Block 3/2.

Plans call for drilling 13 wells, eight producers and five injectors, to begin in September with the Neddrill semisubmersible. Drilling will begin with recompletion and conversion to producer of the 3/2-9 well, drilled in 1988, for a long term production test. The 30 in. conductors and 20 in. casing for all 13 wells were batch set in December-January.

Conoco also began laying the control umbilical and 2, 8, 10, and 12 in. flow lines with the Stena Apache reel barge and the Orelia diving support vessel. Highlands Fabricators built the manifold at Nigg, Scotland.

Production is to begin in October and peak at 18,000 b/d in 1993. Oil will move via flow line to Chevron U.K. Ltd.'s southern Ninian platform for processing and further transmission to Sullom Voe terminal in the Shetland Islands. Lyell associated gas will be used mainly for southern Ninian fuel.

Lyell, discovered in 1975, holds about 400 million bbl of oil in place, Conoco said. About 30 million bbl will be produced in the first phase while viability of other parts of the reservoir is studied.

Lyell interests are held by operator Conoco 33.34% and Chevron and Oryx (U.K.) Energy Co. 33.33% each.

SUBSEA PIPELINE BUNDLE

Rockwater this month completed the initial launch phase of the pipeline bundle from its construction site at Wester Site near Wick in northern Scotland.

It is one of two Rockwater constructed at Wick for Elf Enterprise under a 50 million contract.

The main interfield bundle, to link Piper B and Saltire platforms, is about 7 km long, has a 40 in, diameter, and weighs almost 6,000 metric tons.

The bundle contains four pipelines to transport oil and gas from Saltire and provide gas lift and water injection for the field.

Included are both ends of the ESV assemblies for each of the pipelines. This eliminates the need for separate installation of ESV templates on the Piper B and Saltire platforms plus associated tie-ins.

The second infield bundle is 2 km long, 26 in. in diameter, and weighs 830 tons. It contains three water injection pipelines to link Saltire platform to the subsea wellhead protection unit.

When the launch is complete, the bundles will be towed to the field using Rockwater's controlled depth tow method to install them.

Start-up of Saltire, nearby Chanter oil field, and redevelopment of Piper field with Piper B, a replacement for Piper Alpha platform damaged beyond repair by an explosion and fire in 1988, is scheduled for next year (OGJ, Jan. 13, p. 18).

Interests in the group are operator Elf Enterprise 36.5%, Texaco Britain Ltd. 23.5%, Lasmo North Sea plc 20%, and Union Texas Petroleum Ltd. 20%.

ORWELL CONTRACTS

ARCO's detailed design engineering and procurement contract to ABB Global Engineering Ltd. is for a four well subsea template on Block 50/26a tied back to ARCO's Thames complex 35 km away.

It covers specification and design of subsea cage, controls, pipeline, and associated control umbilicals along with procurement and construction support services.

The distance from the fields to the host Thames platform is the greatest attempted off the U.K. for remote control of a producing commercial field, ABB said.

In the other contract, ABB Global will be responsible for engineering design and procurement to upgrade Thames facilities to receive Orwell field gas, including installation of compression. Orwell gas will be treated on Thames platforms for delivery to the U.K. gas grid.

Orwell, with estimated reserves of 112 bcf, is in the U.K. southern gas basin. Operator ARCO plans start-up in late 1993.

RANGER DISCOVERY

Ranger's Block 22/27a-3 wildcat found oil in targeted zones but was not tested.

Ranger drilled the well, about 150 miles east of Aberdeen, as a deviated hole to 5,850 ft. It then sidetracked the hole and drilled to 8,828 ft.

Site is on the northeast flank of a complex salt diapir feature that straddles the boundary with Block 29/2a. Ranger holds a 14.5% interest in 29/2a, where two earlier exploratory wells had the high flow rates.

Plans call for at least two more appraisal wells on 22/27a and a 3-D seismic survey on both blocks to begin in July. Ranger and Block 29/2a operator Conoco Inc. are discussing further evaluation and development options.

Partners in 22/27a are Ranger 41.62%, Lasmo 23.41%, Enterprise Oil plc 18%, Sun Oil Britain Ltd. 13.22%, and Santos Europe Ltd. 3.75%.

AMERADA STRIKE

Amerada's Block 15/21a-46 test flowed at a stabilized rate of 3,24 b/d of 38 gravity oil through a 40/64 in. choke from upper Jurassic pay.

The well was deviated to 15,782 ft measured depth, 13,890 ft true vertical depth, and found hydrocarbons in several Jurassic zones.

Amerada suspended and is continuing to evaluate the well, which is 6 km from production facilities in Ivanhoe/Rob Roy fields and the designated platform site in Scott field.

Interests are held by operator Amerada 42.084%, Deminex U.K. Oil & Gas Ltd. 43.333%, Kerr-McGee Oil (U.K.) plc 10.833%, and Pict Petroleum plc 3.75%.

BP APPRAISALS

BP's 22/20-4z sidetrack appraisal well on the western flank of Monan field in the Eastern Trough area flowed at a rate of 2,000 b/d of 41 gravity oil through a 40/64 in. choke from Tertiary pay.

Total depth of the sidetrack is 3,132 M.

It is the second well on the Monan structure, and results will be integrated with a 3-D seismic survey to evaluate development potential.

BP also drilled a downdip sidetrack, 22/20-4z, to 3,132 m, confirming the oil/water contact.

Monan field is in 90 m of water about 260 km east of Aberdeen.

On the same block, BP tested its fourth appraisal in Mungo field, The 22/20-5 well flowed 5,650 b/d of 38.6 gravity oil through a 1-1/2 in. choke from Tertiary sands. It was drilled to 2,737 m in the chalk. Well results also will be integrated with the 3-D survey covering Monan field.

Mungo, about 5 km east of Monan, straddles Blocks 23/16a and 22/20. Both fields are part of the diapir play currently proving prolific in the Eastern Trough area.

Partners in 22/20 are BP 62.8%, Murphy Oil Corp. 11.5%, Lasmo plc unit Ultramar Exploration 7.8%, Petrofina SA 5%, and Monument 0.5%

CONOCO APPRAISAL

Conoco tested two appraisals on Block 15/24b about 160 miles northeast of Aberdeen, reported partner Lasmo North Sea plc.

Appraisal well 15/24b-5 flowed 5,464 b/d of 32 gravity oil and 1.79 MMcfd of gas through a 48/64 in. choke from Tertiary sandstone. The West Venture semisubmersible drilled the well to 6,825 ft.

Appraisal 15/24b-6 flowed 2,954 b/d of 37 gravity oil and 720 Mcfd of gas through a 36/64 in. choke from Tertiary sandstone. The Neddrill 6 semisubmersible drilled the well to total depth of 6,613 ft.

The strikes are a few miles southeast of Piper and Tartan fields and near pipelines. Conoco is evaluating well results in the context of possible field development.

Interests are Conoco 60% and Lasmo 40%.

PHILLIPS APPRAISAL

Phillips' 30/13-4 Jacqui appraisal flowed 2,650 b/d of 39 gravity oil and 14.5 MMcfd of gas through a 28/64 in. choke at 6,710 psi flowing wellhead pressure on drillstem test of pre-Cretaceous pay. Total depth is 15,011 ft.

Testing was restricted by pressure and temperature limits of the equipment.

Plans call for a major 3-D seismic survey later this year as part of a program of early evaluation, appraisal, and development.

The February 1990 discovery well 30/13-3 flowed 36 gravity oil from a similar pre-Cretaceous section at a stabilized rate of 7,600 b/d from one zone and as much as 4,400 b/d from a second.

Interests in the block are Phillips 35%, Fina Exploration Ltd. 30%, Agip (U.K.) Ltd. 15%, Lasmo 8.52%, Gas Council (Exploration) Ltd. 7,22%, and Elf U.K. plc 4.26%.