September 1998 Vol. 219 No. 9  Production

Robert E. Snyder,  Editor

Ekofisk redevelopment; other technology advances

Phillips Petroleum Co.'s big North Sea redevelopment project, Ekofisk II, began producing oil and gas on August 18, on schedule and under budget. Four years in the making, the project will let the company produce profitably from Norwegian North Sea fields through at least 2028. The project significantly reduces operating costs through consolidation of facilities. Phillips says it installed the facilities 30% faster than industry average and built the most automated development drilling rig in the North Sea — 'even during a time of rapidly increasing service/construction costs, the project was delivered 20% under budget.

Ekofisk II comprises two new platforms: one for drilling and production, and one for processing and transportation. The operator phased out or modified 14 existing platforms and installed 31 miles of new pipeline. Total cost of the project was $2.5 billion. Production capacity is expected to be 306,000 bopd and 789 MMcfgd, about 20% above initial expectations.

Phillips discovered Ekofisk in 1969, and began production in 1971. The redevelopment project began in response to the subsiding seabed, new and more stringent safety regulations, and high operating costs due to older, labor-intensive technology. Authorities gave the project the go-ahead in 1994. As part of the plan, an agreement between Phillips and Norway's Ministry for Oil and Energy extended the license period to 2028 from 2011, and gave the Norwegian state a 5% interest in Ekofisk, beginning Jan. 1, 1999. The field has produced more than 1.4 billion bbl oil, and another billion bbl is expected to be produced through 2028.

Phillips has a 36.96% interest in Ekofisk, and operates on behalf of other members of the Phillips Norway Group: Fina Exploration Norway SCA, 30%; Norsk Agip A/S, 13.04%; Elf Petroleum Norge A.S., 8.45%; Norsk Hydro Produksjon a.s., 6.7%; Total Norge A.S., 3.5%; Statoil, 1%; and Saga Petroleum ASA, 0.3%.

As one fallout of the project, gas and condensate output ceased from Statoil's Tommeliten Gamma field after almost 10 years onstream. This is the first Statoil-operated field to be abandoned off Norway. It was shut down by the abandonment of Phillips' Edda platform, which received production from Tommeliten. The field began operation in 1988, and has produced about 350 Bcf gas and 24 million bbl oil via an 11-km flowline to Edda, which was shut down by the Ekofisk II redevelopment.

Statoil is working to find a way of reusing both the template and flowlines from Tommeliten. The six wells on the field will be plugged in 2000, but activity on the license area is continuing, with an exploration well planned early next year in the Alpha structure, 6 to 7 mi south of Gamma.

Positive subsea tree forecast. As reported in Offshore International Newsletter, more than 200 subsea trees are forecast to be installed internationally this year, 18 more than 1997's total. Thirty three installations had been confirmed through mid-July, and another 244 trees were in various stages of planning, construction, delivery or installation.

Brazil and the North Sea continue to lead in the number of trees planned for installation; but OIN says other major oil-producing regions continue to experience steady growth. Subsea developments in the U.S. Gulf of Mexico, Angola and Australia are noted as "steadily increasing."

In one notable West African development, Elf Exploration Angola announced go ahead for development of Girassol field, located in Block 17. Hydrocarbons will be produced through subsea production systems connected to an FPSO. A $220-million contract was given to Kongsberg Offshore, an FMC Corp. subsidiary, to supply the subsea equipment, including wellheads, trees, manifolds, flowline connectors, controls and intervention equipment.

Well completion advances. In what is claimed as a world first for new sand control technology, a major breakthrough has been achieved by Aberdeen-based Petroline Wellsystems with the successful installation of the world's first open-hole expandable sand screen (ESS) in a Shell Expro well in the Southern North Sea. And what the developers say is the first new approach to sand control in many decades is now commercially available for open, cased hole and remedial applications.

The system comprises a sand exclusion screen capable of considerable expansion when a cone-shaped mandrel is driven through it. This allows the screen to be run in a pre-formed condition, then expanded in the wellbore to press directly against the formation wall. The screens feature expandable connections, allowing any length of screen to be run, with expansion over the entire length. Being expandable, it offers a "remedial capability" with the potential to save significantly in well workover costs. The company has also carried out a wide range of lab "proving" tests with the integral filtration medium, as well as full mechanical testing of all other components.

ESS is described as a "sandwich," comprising three layers. The inner layer, or base, is slotted using a proprietary manufacturing process. Overlapping leaves of a specially developed filtration medium are wrapped around this and then a "micro" slotted cover is wrapped around the screen medium, protecting against damage during installation.

For advantages, the developer says, "Gravel packs are good for controlling sand but can be risky / expensive to install; traditional screens are easy and relatively cheap to install, but are prone to plugging and failure. The ESS expands against the borehole, providing support, eliminating the annulus and reducing sand movements, fines migration and associated plugging. It can also be installed as quickly and as easily as traditional screens."

API Y2K survey. API will lead a survey to find out what is being done within the petroleum industry to solve the Year 2000 computer problem. It will gather data from industry associations in the U.S. and Canada, and its own member companies, in response to a broad request from the government for information about a variety of U.S. industries.

API was named to coordinate the survey by the Federal Energy Regulatory Commission. The contact for more information is Michael Shanahan, tel: 202 682 8128.

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