PORCUPINE BASIN FRONTIER TRACTS AWARDED OFF WESTERN IRELAND

Dublin has awarded eight exploration licenses covering 32 blocks in the northern Porcupine basin frontier of the Atlantic Ocean west of Ireland. (73867 bytes) One of the licenses covers a 16 year old discovery that might pave the way toward Ireland's first commercial oil production.

March 27, 1995

4 min read

Dublin has awarded eight exploration licenses covering 32 blocks in the northern Porcupine basin frontier of the Atlantic Ocean west of Ireland. (73867 bytes)

One of the licenses covers a 16 year old discovery that might pave the way toward Ireland's first commercial oil production.

The licenses, awarded under a round opened in January 1994, require acquisition of a total 7,700 line km of seismic data. Surveys are to be conducted by the end of 1997 as part of a four phase work program. Licenses, each covering about 100 sq miles, carry no initial drilling commitment, although eventual drilling is required to achieve their 15 year terms.

Eleven applications were filed for blocks originally offered (OGJ, Jan. 24, 1994, p. 21). The lightly explored region is thought to be geologically similar to the West of Shetland area, where an exploration play is emerging (OGJ, June 20,1994, p. 16).

"Since revised licensing terms were announced toward the end of 1992, there has been a significant increase in the level of exploration interest in Ireland," said Emmett Stagg, Ireland's minister for transport, energy, and communications.

"This often results in refreshingly positive measures being proposed."

Ireland's petroleum tax regime includes a 25% corporate levy.

The Porcupine basin is a large sedimentary area 100-250 km west of Ireland, with water depths increasing from 300 m in the north to 2,000 m in the south.

"The basin is underexplored and has significant potential for oil and gas discoveries," Stagg said. "It was declared as frontier acreage because of difficulties relating to its physical environment."

Here are the blocks and licensees:

Part of Block 26/28, Block 26/29, Aran Servicing Ltd., Dublin, 100%. A possibly commercial oil strike lies on Block 26/28. An affiliate, Aran Energy plc, earlier acquired a 20% interest in three blocks in Grid 27 as part of group led by Kerr-McGee Oil Corp. (see map, OGJ, Mar. 28,1994, p. 28).
Blocks 35/26, 35/27, 43/5, 44/1, operator BHP Petroleum Exploration Inc. 60%, Santa Fe Minerals (Ireland) Ltd. 25%, British-Borneo Petroleum Syndicate plc 15%.
Blocks 35/4, 35/8, 35/9, operator Chevron Exploration Europe Ltd. 80%, Aran 20%.
Blocks 34/15, 34/20, 35/16, operator Chevron 80%, Aran 20%.
Blocks 35/19. 35/29, 35/30, 36/21, 36/26, 44/4, 44/5, operator Marathon Petroleum Hibernia Ltd., Occidental of Ireland Inc., Phillips Petroleum Co. all equal shares.
Blocks 35/1, 35/2, 35/6, 35/7, Oxy.
Blocks 34/24, 34/25, 34/30, 35/21, east half 35/23, 35/24, operator Statoil (U.K.) Ltd. 27.5%, Fina Petroleum Development Ltd. 27.5%, Conoco (U.K.) Ltd. 20%, Union Texas Petroleum Ltd. 15%, Seafield Resources plc 10%.
Blocks 35/17, 35/22, west half 35/23, 35/28, operator Total Oil Marine plc 80%, DSM Exploration Ireland BV 20%.

Stagg said further Porcupine basin licenses will not be offered for a time, although companies can continue to apply for acreage in other offshore areas under Ireland's open door policy

COMMERCIAL DISCOVERY?

The Porcupine basin has seen the drilling of only 25 wells, some of which tested oil and gas.

Aran said the region's only potentially commercial strike is Connemara field, a deepwater discovery on the company's license in Block 26/28.

Data compiled by Wood Mackenzie Consultants Ltd., Edinburgh, show that a group led by BP drilled the discovery well, 26/28a-1, in 1979. Drilled to 10,873 ft in 1,246 ft of water by the Sedco 703 semisubmersible rig, the well flowed a combined 5,589 b/d of 32-38 gravity oil on three tests of upper and middle Jurassic pays.

BP dropped its license in 1989 after a disappointing appraisal program. BP's well 26/28a-2, a confirmation hole drilled to 9,797 ft on the western edge of the structure, flowed 1,120 b/d of 39-41 gravity oil from a new pay Three later wells were dry

Aran held an interest in the BP wells. After BP dropped its interest, Aran received another license covering Block 26/28. The latest award amounts to an extension of that license.

The Irish company's newly won license surrounds the Connemara discovery, which it credits with 20-50 million bbl of proved and probable reserves.

Aran points out that advances in technology such as floating production systems have reduced costs and thus improved the economics of oil recovery in frontier regions such as West of Shetland and the Porcupine basin.

The company is assessing possible development programs for Connemara, including leasing of reusable equipment and "innovative" financial arrangements. It plans an extended well test next year in which the reservoir can be flow tested to determine its characteristics.

If results are favorable, Aran hopes to begin phased development of the field.

Ireland has no oil production. Marathon's Ballycotton and Kinsale Head gas fields are on stream off the southern coast of the country.