NPD hikes Norway shelf resource estimate

Norwegian Petroleum Directorate, Stavanger, estimated recoverable resources on the Norwegian continental shelf at 12.5 billion standard cu m of oil equivalent, comprised of 6.5 billion cu m of oil and 6 billion cu m oil equivalents of gas.

The range of uncertainty in the total estimated is 9.5-16.5 billion standard cu m of oil equivalent.

The estimate for the discovered resources varies from 7.5-10.5 billion cu m of oil equivalent, with an expected value of 9 billion cu m. Considerable uncertainty exists regarding undiscovered resources; the estimates range from 2-6 billion cu m. The expected value of undiscovered resources is 3.5 billion cu m.

The new estimate is an increase of 1.7 billion cu m from the February 1995 resource report. This is mainly due to an upward adjustment NPD made on expectations for a future increase in the recovery factor for the resource on the continental shelf.

Based on an expectation that 50% of the oil in place and 75% of the gas in place will be recovered, resources from possible measures for increased recovery are estimated to be 790 million cu m of oil and 420 billion cu m of gas. The rest of the increase results both from new discoveries and upgrading of elder fields and discoveries. The total increase corresponds to about 83% of the total oil and gas production from the Norwegian continental shelf during 1971-97.

Norwegian production accounted for 4.3% of 1995 world oil production of 67.5 million b/d. It is estimated that Norway has about 1.3% of the world's discovered recoverable oil resources and about 1.8% of the gas.

Cumulative production from the shelf through yearend 1996 is 1,493 million standard cu m of oil, 492 billion cu m of gas, and 48 million metric tons of NGL. NPD, based on information given by operating companies, forecasts that production will peak at 3.7 million b/d by 2001, with uncertainty varying from 3.2-4.4 million b/d. The forecast is based on the resources currently entered in the resource account.

Operators have made 196 discoveries off Norway since the first exploration well was drilled in 1965. They have placed on production or decided to develop 54 fields. Plans exist to develop 36 more discoveries, leaving 93 lacking concrete development plans. Some of the 93 are likely to be developed in response to vacant capacity on existing installations and a future increased market for gas.

Operators have made 20 discoveries in the last 2 years, giving a resource growth of about 260 million cu m of oil equivalent. The discovery rate is still high, around 48% the last 2 years. This compares with about 38% since 1965. n

Publications

Interpretation of Three-Dimensional Seismic Data, Fourth Edition, AAPG Memoir 42, by Alistair R. Brown, published by American Association of Petroleum Geologists, Box 979, Tulsa, OK 74101-0979. 456 p., $89.

The author notes that the largest single development in 3D interpretation techniques since publication of the third edition is the generation, display, and use of seismic attributes. The fourth edition has a new chapter on the subject.

It also has many new examples and procedural diagrams in an attempt to bring the treatment of every aspect of 3D interpretation up to date.

World Fiscal Systems for Oil-1997, published by Barrows Inc., 116 E. 66th St., New York, NY 10021. 2,000 p., $1,800.

This is an analysis and rating of 324 fiscal systems in 159 countries.

Geophysical

Ensign Geophysics, Twickenham, England, received a U.K. patent for wavefield reconstruction.

This seismic data processing technique operates by combining shot record interpolation with a de-aliasing procedure.

After wavefield reconstruction, both the coherent energy and character of the data are similar to that acquired with a higher fold of coverage using a reduced shot interval. The technique also improves the performance of many pre-stack multichannel applications in processing, such as dip moveout correction and pre-stack time migration, and multiple attenuation techniques.

Algeria

Sonatrach let a contract to Gustavson Associates Inc., Boulder, Colo., for a $4.1 million, 2 year geologic study of oil and gas potential in the frontier Bechar, Ahnet, and Timimoun basins.

Newfoundland

A 10 company group let by Husky Oil let a contract to Petroleum Geo-Services ASA, Oslo, for a 3D seismic survey 300 km east of St. John's.

The contract for more than 45,000 CMP km is the largest survey conducted off Canada. The companies are Husky, Petro-Canada, Chev- ron, Gulf, Murphy, Mobil, Talisman, Parex, Norsk Hydro, and Mosbacher.

Husky will supervise operations for Whiterose field and the Cape Race exploration license. Petro-Canada will supervise operations for Terra Nova and Hebron-Ben Nevis fields.

Mongolia

Snyder Oil Corp., Fort Worth, reported a discovery on Contract Area XXI at the first of four planned 1997 wells in the country.

The Sotamo 21-2 tested three Lower Cretaceous and Upper Jurassic zones; two produced oil. A DST at 6,130-96 ft recovered paraffinic oil. This is the first oil discovered in this stratigraphic interval in the Tamtsag basin.

A DST at 5,419-5,510 ft recovered paraffinic oil from an interval stratigraphically equivalent to the productive interval in the Sotamo 21-1 well 1.9 miles north-northeast on a separate geologic feature.

The other DST, at 6,597-6,663 ft recovered load water, filtrate, and no oil. TD is 8,038 ft. This well is 95 miles east of the first discovery well on Contract Area XIX.

Thailand

Pogo Producing Co. and partners plan to drill 30 wells this year on Gulf of Thailand Block B8/32, where they have drilled 50 wells.

Three wildcats on the Benchamas North seismic structure encountered only modest hydrocarbon accumulations. The wells are disappointing but do not condemn the feature, Pogo said.

The Pogo group started up Tantawan field Feb. 1 (OGJ, Feb. 24, 1997, p. 45). It plans to start up Benchamas field around April 1999. The block has numerous exploratory opportunities, including the Maliwan structure and the Pattalung-Yungthong trend, both to be explored by yearend.

California

Plains Resources Inc., Houston, plans an active exploitation program to hike recovery from giant Montebello oil field in Los Angeles County.

The 500 acre field has produced more than 100 million bbl of 22° gravity crude and 100 bcf of gas from two compartmentalized reservoirs at 1,500-4,000 ft. It produces 800 b/d on a 4-6%/year decline plus 800 Mcfd of gas from 55 wells. Water injection is 10,000 b/d.

Plains hopes to boost production 20-30% by yearend via tubing rotators, pump-off controllers, stimulations/recompletions, and other remedial work. It also hopes to drill 30 infill producing wells plus a number of injectors by yearend 1998.

With OOIP estimated at 400 million bbl, Plains expects to recover at least 20 million bbl, including 9 million bbl proved developed. Ultimate recovery might be 30-40% of OOIP, the company said.

Kansas

Stelbar Oil Corp., Wichita, staked a horizontal well to Pennsylvanian Morrow about a mile east of Johnson City Townsite oil and gas field.

The 1 Plummer, in 36-28s-41w, Stanton County, is to go to Morrow at about 5,400 ft TVD. It would be the state's first horizontal well in Morrow, PI/Dwights reported.

Michigan

Five more horizontal wells are planned to Devonian formations in the state, PI/Dwights reported. They are:

Dart Oil & Gas Corp., Mason, Mich., 4-22 Hamming, in Riverside field, Missaukee County, to Dundee at 6,000 ft TVD.

Dart 10-29 Fankhauser and 9-31 Benchley, in Winterfield field, Clare County, to Dundee at about 3,800 ft.

Ranch Production Co., Englewood, Colo., 9-11 Salla, in North Buckeye field, Gladwin County, to Dundee at 3,600 ft.

Newstar Energy USA, Monroe, Mich., 1 Johnson, in Standish field, Arenac County, to Richfield at about 4,100 ft.

Newstar earlier applied for permits for horizontal Dundee tests in Beaverton field, Gladwin County, and Freeman-Redding field, Clare County.

Ohio

The state Division of Geological Society sought participation from producers and service companies for an EOR project under Petroleum Technology Transfer Council auspices in East Canton field, Stark and Carroll counties.

Wells on 40 acre spacing have produced 86.5 million bbl of primary recovery from 1.5 billion bbl of OOIP in Silurian Clinton sandstone since 1908. Remaining primary oil target is put at 51.8 million bbl.

Oklahoma

Unit Corp., Tulsa, plans to complete a 1.5 mile southwest stepout from Verden field that logs indicate encountered one of the thickest gross sand intervals in Pennsylvanian Springer in the area.

The 1 Dorsey, on the Laverty prospect in Caddo County, cut 476 ft of gross sand (370 net ft) in Springer. TD is 19,560 ft. Unit expects to start drilling two more wells by third quarter on the 3,950 net acre prospect.

Texas

West
Drilling could start in second half 1997 under a Matador arch exploration agreement.

Apache Corp., Houston, and Toreador Royalty Corp., Dallas, will explore 22,500 acres in Motley County north and east of the Roaring Springs complex of three fields. The fields have produced more than 9 million bbl of oil from Permian Wolfcamp reefs as deep as 4,500 ft.

Apache is starting a 3D seismic survey over 9,500 acres that include five well Matador field.

Utah

Conoco Inc. plugged a Kaiparowits basin wildcat in Wayne County. TD is 8,700 ft at the 1 Teasdale, in 16-30w-6e, 24 miles south of idle Last Chance gas field. Rangeland Petroleum Corp. drilled the well to 6,000 ft.

Wyoming

River Gas Corp., Northport, Ala., staked a coalbed methane wildcat in Sweetwater County. Cretaceous Mesa- verde at 5,000 ft is the objective at the 35-4-1 UPR, in 35-23n-102w, 10 miles north-northeast of Superior, PI-Dwights reported.