INNOVATIVE DRILL RIG TECHNIQUE SETS TONE FOR FUTURE

The Zapata Off-Shore Company, Houston, in association with the Bendix-Skagit Company, Washington, has developed a mooring system for offshore semi-submersible drilling rigs capable of permitting uninterrupted operations in water depths as deep as 610 m and in 9-12 m wave sea conditions. The system, which is claimed to be the first successful integration of chain and wire rope, consists of eight lines, each made up of 762m of 2-3/4 (7 cm) chain and 1371.6m of 7 cm wire rope. There are eight anchors each weighing 20 tons. The chain and wire rope are connected by a patented connector link. The system is designed so that anchors can be run out, set and retreived using conventional anchor handling workboats and permanent equipment installed aboard the rig itself. This article briefly reviews the first two years' experience of the system in operations with the Zapata Class 2000 rigs in the Gulf of Mexico. Order from BSRA as No. 54,676.