A Deep-Water Platform in the Santa Barbara Channel

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This paper describes the construction, transportation, connection, launch, and erection of a deep-water platform in 850 ft of water in the Hondo field of the Santa Barbara Channel. All phases of construction and the problems that were overcome are discussed. Introduction A new water depth record of 850 ft was set by Exxon Co., U.S.A., with the Hondo platform in the Santa Barbara Channel. The challenge of constructing the Hondo platform was met with innovative techniques that evolved platform was met with innovative techniques that evolved from engineering and construction practices in the Gulf of Mexico. In Feb. 1968, Exxon Co., U.S.A., leased more than 360 sq miles in the Santa Barbara Channel off southern California. In the fall of 1970, 19 leases were unitized into the Santa Ynez Unit, located approximately 23 miles west of Santa Barbara and 5 miles south of Gaviota. The Hondo platform was erected in Federal Block OCS-P-0188, which varies from 300 to 1,300 ft deep. The Hondo platform is in 850 ft of water at a latitude of 34 deg. 23'26.71" and longitude of 12W deg. 7'13.80" and is a single integrated platform performing all basic functions (drilling, production, and housing of personnel). In Oct., 1974, Exxon signed a contract with J. Ray McDermott and Co., Inc., to construct the Hondo platform. McDermott subcontracted the land-phase platform. McDermott subcontracted the land-phase construction of the jacket to Kaiser Steel Corp. This contract provided for construction of deck units and piling for a lump sum at McDermott's Louisiana facilities and for erection of the total platform at a day-rate cost. The subcontract provided for construction of the jacket on a cost-plus bas is with an efficiency incentive clause at Kaiser's California facilities. When the contract was signed, the scheduled completion date for erection of the platform in Santa Barbara Channel was Sept. 16, 1976. Subsequently, we decided to drive the conductor pipes with the derrick-barge spread instead of drilling and grouting these pipes with the drilling rig. This conductor-pipe driving operation was scheduled for 30 days. The platform and conductor pipes were completed in early Nov. 1976, less than 1 month later than originally scheduled. This study reviews the land-phase construction and the water-phase erection of the Hondo platform, highlighting the use of unique designs and reviewing problems. Physical Features Physical Features The platform (Fig. 1) is a 28-well conductor, pile-founded structure that will support a drilling rig, pile-founded structure that will support a drilling rig, production equipment, and personnel quarters. production equipment, and personnel quarters. The three-level, 86- x 170-ft deck has a total usable area of about 1 acre. The top deck is 95 ft above the water line and 945 ft above the mud line. The jacket is 45 x 125 ft at the water line and 170 x 235 ft at its base, has eight legs and 12 skirt-pile sleeves, and is framed with cross and diagonal bracing. The eight legs are 54 in. in diameter. The main piles driven through these legs are 48 in. in diameter and penetrate 340 to 375 ft into the channel floor. The skirt-pile sleeves are 63 in. in diameter and the skirt piles are 54 in. in diameter; skirt piles penetrate 255 to 260 ft into the ocean floor. piles penetrate 255 to 260 ft into the ocean floor. The jacket is composed of upper and lower sections that were built on land and then transported independently to location on a launch barge. JPT P. 498