SHELL'S BIG AUGER TLP PROJECT PROGRESSING

Shell Offshore Inc. is pressing a project that will see installation of a record setting platform in the Gulf of Mexico.

The company by yearend will tow the Auger tension leg platform (TLP) into the gulf for installation in 2,860 ft of water on Garden Banks Block 426.

When installed early in 1994, the Auger TLP will claim the gulf's water depth record for a permanent drilling and production platform and the world water depth record for TLPS. Auger's wells will best by nearly 800 ft the gulf's water depth record for producing wells.

From seabed to the top of the flare tower, the Auger TLP will stand 3,280 ft tall.

Shell's Auger prospect covers parts of Garden Banks Blocks 426, 427, 470, and 471, all 100% Shell owned tracts.

Gross oil production from the $1.2 billion development is expected to peak in 2001 at about 46,000 b/d and gas output at 125 MMcfd. Auger oil is to move by pipeline 72 miles to a platform in 243 ft of water on Eugene Island Block 331. Gas will flow 38 miles to a platform in 398 ft of water on Vermilion Block 397.

Auger's gross ultimate recovery is expected to total about 220 million bbl of oil equivalent (BOE) with a 2:1 oil-gas ratio.

Shell completed the Auger discovery well in May 1987 in 2,862 ft of water on Garden Banks Block 426. The well was drilled by the Zane Barnes semisubmersible rig. Since 1990, Shell has predrilled 10 wells on the Auger unit with the George Richardson semi-submersible.

AUGER FIELD

The Auger prospect is a shallow salt dome and deep salt ridge with large down-to-east and down-to-north fault systems, expressed on the sea floor as a topographic high covering about 2,800 acres. Turbidite sands of variable but mostly good reservoir quality onlap the deep ridge. Auger's stratigraphic section thickens to the southwest.

Auger field has 340 ft of net pay in four stacked Pliocene-Pleistocene reservoirs at 15,000-19,000 ft subsea. The two shallower sands - N and O - contain mostly condensate rich gas pays, while the lower Q and S zones hold mostly oil. More than half the field's estimated reserves-122 million BOE-occurs in the S sand.

Porosity ranges from 29% in the N and 0 sands to 24% in the S sand. Permeability declines from a high of 900 md in the N sand to 150 md in the S. Shell has proposed various fan models to explain log patterns and sand qualities.

Auger's N and 0 sands appear to be channel features occurring in the upper fan area with variable correlatability, depending on relative fan system position. The Q sand is thought to be a stacked, midfan lob and channel sequence topped by a more channel-like sand similar in some ways to the sand.

Shell interprets Auger's S sand as a finely laminated sand and shale sequence in a distal to lower fan position, grading upward to blocky log shapes and displaying a high degree of correlatability.

Six of Auger's predrilled wells were spaced widely along the updip flank of the S reservoir to provide a correlation section to test the continuity of the sand facies. Another well was drilled middip into the S sand to test deeper zones.

TLP DETAILS

The Auger TLP is a 39,000 ton structure designed and engineered by Shell. Major components include the deck with drilling and production equipment, hull, tendons, foundations, and lateral mooring system.

McDermott International Inc. fabricated Auger's 70 ft tall, 290 ft by 330 ft deck at Morgan City, La. Auger's integrated drilling rig is designed for drilling and workover operations to 25,000 ft.

TLP topsides include 32 well slots around a 75 ft by 200 ft rectangular well bay; separation, dehydration, and treatment facilities for as much as 46,000 bid of oil, 125 MMcfd of gas, and 25,000 b/d of produced water; and an accommodation module for 112 persons.

Wells on the seabed are arranged in a 98 ft by 206 ft oval with 16 ft spacing. There is no wellhead template.

Italy's Belleli SpA fabricated the TLP hull, mainly at Taranto, Italy. The hull consists of four 74 ft wide, 159 ft tall columns connected by four rectangular steel pontoons, each 35 ft wide and 28 ft high.

Various companies manufactured parts of Auger's 12 tendons in the U.S. and Scotland. Auger has three tendons to a corner, each 26 in. wide and 2,760 ft long.

Each of Auger's four foundations consists of a 30 ft tall, 60 ft by 60 ft template held in place by four 72 in. by 427 ft piles. Aker-Gulf Marine fabricated Auger's four foundations and assembled the tendon sections at Ingleside, Tex. The foundations were installed late in 1992.

Auger's lateral mooring system consists of eight lines arranged in a 9,000 ft radius circle. Each mooring line is composed of 8,650 ft of 5 in. wire rope and 1,800 ft of 5'/16 in. chain. Mooring line tension is maintained by Liviar winches and takeup reels in the hull columns.

Shell expects to begin placing Auger's predrilled wells on line early in 1994 in 4,000-5,000 b/d increments.

At least two wells must be completed before production can begin. All 10 predrilled wells are to be completed by yearend, after which Shell will begin drilling at least four development wells. Auger's lateral mooring system will position the TLP over each development well.

Four steps remain to complete the Auger TLP installation:

Installing the preset portion of the lateral mooring system.
Towing the TLP to location on Block 426.
Connecting the TLP superstructure to the lateral mooring system.
Installing and connecting Auger tendons.

McDermott is to install the preset part of the lateral mooring system this year using Derrick Barge 50 (DB50). Following connection of the TLP deck and hull to Auger's tendons, DB50 is to move to shore to rig up for pipeline installation, then return to Auger field to install and tie in the last 3 miles of the facility's 12 in. oil and gas pipelines.

McDermott installed the shallow sections of Auger's pipelines in mid-1992 using DB28. DB50 installed Auger deepwater pipeline sections in April 1993 using the near vertical J-curve pipelaying technique, only the second commercial J-lay application in the Gulf of Mexico and the deepest water location.

McDermott in October 1993 mated the Auger deck and hull on Galveston Block A-206 in the Gulf of Mexico about 70 miles south-southeast of Freeport, Tex.

Once the deck and hull were mated, the superstructure was towed to Freeport for hookup and commissioning of topside instrumentation-including production, processing, electrical, piping, and structural systems-in preparation for final installation on Block 426.