Marathon Launches New Shallow-Draft Cantilevered Drilling Platform
A unique shallow-draft, selfcontained and self-elevating cantilevered drilling platform was launched November 22 from Marathon's Brownsville, Texas, shipyard. The new Marathon 150-44-C class platform is being constructed for Chiles Offshore Limited, Houston. It was officially christened December 16 as the Texas Star, and is expected to begin work soon in the Gulf of Mexico for Mobil Oil Company.
Marathon engineers point out that the relatively small rig—148 feet long by 160 feet wide—can drill multiple wells in one location in water depth as shallow as 15 feet, and as deep as 150 feet. The unit's hull depth is only 16 feet. The rig's unusual 250-foot-long spud legs are designed to recess into the bottom of the hull—allowing towing over shoals as shallow as 13 to 15 feet.
Development of the 150-44-C cantilevered platform was aimed specifically at relatively shallowdrilling environments such as the Caribbean, the west coast of Africa, and the coastal areas of Indonesia, all of which are comparable to the Gulf of Mexico.
The platform is outfitted for up to 15,000 feet exploratory and development drilling, and heavy duty workover of existing satellite wells or wells of a development platform. A full crew of 40 or more can be accommodated in modern quarters aboard the unit. A Marathon spokesman pointed out that as a result of the uniquely versatile cantilever design, the 150-44-C unit includes provisions for drilling multiple wells without relocating the rig. The cantilever feature provides that the rotary can be located from 10 to 35 feet out from the end of the jackup hull, and 7y2 feet on either side of the center line, for a 15 by 25-foot drilling platform.
The soon-to-be-christened Texas Star rig has a substructure 24 by 38 feet wide by 14 feet high. When required, the substructure, drill floor and mast can be skidded on the deck of a production platform, and span 30, 40 or 45- foot-wide skid beams with a 10- foot clear height above the platform deck.
Clay Chiles, president of Chiles Drilling Company, general partner of Chiles Offshore Limited, has had many years of experience in land and offshore drilling. The company is located in Houston. Marathon LeTourneau Company, Marine Division, is a subsidiary of Marathon Manufacturing Company, Houston. The parent firm is a multiproduct company serving industries in marine construction and t r a n s p o r t a t i o n , heavy equipment and steel products, as well as a group of diversified companies producing chemicals, batteries, consumer goods and providing paving and utility services.