The extreme water-depth over the Hondo Field in Santa Barbara Channel was the principal factor which made the construction of Exxon's Hondo platform unique. Completion of construction on schedule made the project note-worthy.
Components of the platform were fabricated in two states, California and Louisiana. Elements of the jacket were fabricated in four plants in California and transported to Oakland for assembly. The jacket was constructed in two pieces with the eight legs initially connected by flange and with four stabbing cones for marine realignment and joining. Each jacket section was separately transported and launched. Following launching, the two jacket sections were joined while floating and all eight legs were permanently connected by welding from inside of the legs in dry water tight chambers. The jacket was towed to the erection site and upended by remotely controlled flooding and set on the sea floor. The bulkheads, which compartmented the legs, were removed and the world's longest piles were driven.
Exxon has set a new water depth record of 850 feet with the Hondo platform in Santa Barbara Channel. The challenge of constructing the Hondo platform was met with innovative techniques which evolved from engineering practices developed in the Gulf of Mexico. This paper will review the land phase construction and the water phase erection of the world's deepest water platform, highlighting the utilization of unique concepts and reviewing problems.
In October 1974, Exxon signed a platform construction contract with J. Ray McDermott & Company, Inc. for construction of the Hondo platform. McDermott subcontracted the land phase construction of the jacket to Kaiser Steel Corporation. The platform and conductor pipes were completed in early November, 1976, within one month of the original schedule.
The platform (Fig. 1) is a 28- well conductor, pile-founded structure that will support a drilling rig, production equipment and personnel quarters.
The three level 86 × 170 foot deck has a total usable area of about an acre. The top deck is 95 feet above the water line and 945 feet above the mud line.
The jacket is 45 × 125 feet at the water line and 170 × 235 feet at its base. It has 8 legs and 12 skirt pile sleeves, and it is framed with "x" and diagonal bracing. The 8 legs are 54 inches in diameter. The main piles driven through these legs are 48 inches in diameter. They penetrate 340 to 375 feet into the Channel floor. The skirt pile sleeves are 63 inches in diameter, and the skirt piles are 54 inches in diameter. Skirt piles penetrate 255 to 260 feet.
