The deck for the Enchilada platform measures 95 x 210 ft and includes four levels, making it one of the largest decks installed on a four-pile jacket.The Enchilada production platform, in Garden Banks Block 128, will serve both as a production platform for the Enchilada field and as a pipeline throughput hub for production from Gulf of Mexico fields.
The Enchilada development is a joint venture of Shell Offshore Inc., Amerada Hess Corp., and Pennzoil Co. Shell is the operator.
The Enchilada platform, installed in early 1997, is scheduled to start producing oil and gas in the third quarter 1997. The facilities can handle 60,000 bo/d and 400 MMcfd of gas. The deck structure and production facilities were designed by Alliance Engineering Inc., Houston.
Alliance says the 4,400-ton lift weight of the Enchilada deck and facilities set a Shell record for a single lift in the Gulf of Mexico. The platform represents the next generation of lightweight, space-efficient offshore facilities, according to Alliance.
Mike Mahoney, project manager/project engineer for Alliance, says weight control governed the topsides design. The topsides design was limited by jacket capacity to an operating load of 8,750 tons, much of it needed for drilling.
As a result, he says, the production facilities weigh significantly less than conventional designs. Mahoney indicates the design incorporated weight-reduction measures in virtually all aspects of facilities engineering-from process design and vessel sizing to equipment layout, component selection, and structural design.
The completed deck measures 95 x 210 ft and includes four levels, making it one of the largest decks installed on a four-pile jacket, according to Alliance. The lightweight, four-leg jacket sits in 630 ft of water. The design incorporates a 24-slot combination well bay/riser bay to reduce wave load on risers.
The installation includes:
- Production facilities with a 400 MMscfd and 60,000 bo/d capacity
- Pipeline booster-pump station with an additional 150,000 bo/d throughput capacity
- Pipeline slug catcher and sales-gas compression for 170 MMscfd
- Pipeline hub facilities to several pipeline systems with export capacity exceeding 1.2 bcfd sales gas and 250,000 bo/d
- Riser capacity for 18 pipelines
- Sales-gas meter with a 750 MMscfd capacity, expandable to 1.25 bcfd
- Segregated high sulfur and low-sulfur oil production/sales trains.
The deck is designed for a minimum area, self-erecting (MASE) drilling rig. Alliance says MASE drilling rigs allow for continuous production without needing costly shutdowns or a derrick barge for rigging-up or down.
Installed power generation totals 15 megawatts. A 70 MMBTU/hr waste-heat recovery system provides process heat requirements. This system is the largest ever by Shell Offshore Inc., according to Alliance.
The design, fabrication, and installation of the Enchilada deck took only 22 months on a compressed fast-track schedule. These facilities can be expanded if other prospects in the Garden Banks area prove out, Alliance says.
Facilities for a second platform, in the area, are being designed by Alliance Engineering. These drilling and production topsides will be installed on the Salsa platform, Garden Banks Block 172, jointly owned by Shell and Amerada Hess. Deck loadout is scheduled for Fall 1997 with production to start in 1998.
One pipeline system tied into the Enchilada platform is the Garden Banks Gas Pipeline LLC system (owned by units Shell Oil Co. and Amerada Hess Corp.). This system includes 50 miles of 30 in. from the Enchilada platform to South Marsh Island Block 76 (OGJ, Oct. 28, 1996, p. 28).
The system gathers production from deep water, such as Shell's Auger tension-leg platform, and shelf-edge gas and redelivers it to existing offshore transmission systems. During 1997-2002, capacities available for subscription are 420-710 MMcfd, increasing to 1 bcfd after (OGJ, Oct. 28, 1996, p. 28).
Copyright 1997 Oil & Gas Journal. All Rights Reserved.
