Developers set drilling pace

Thums four man-made islands each have a rock perimeter - 160,000 tons of granite - and an inner core of 900,000 yards of hydraulically placed dredged-sand fill. Because of the shallow depths of Long Beach Harbor, islands were constructed instead of installing conventional drilling and production platforms. The majority of drilling rigs and their equipment - casing racks and mud tanks - are mounted on steel rails and moved by hydraulic jacks at a rate of 3/4 ft/min. Each island has a central plant supplying mud and kill fluid services. Logging and perforating are performed by conventional land-based equipment. Many of THUMS' wells are drilled at exceedingly high angles to reach reserves beneath the harbor or Long Beach's downtown area. All but six or seven of the more than 800 wells are deviated, at angles ranging from 0 to 80/degree/, with an average deviation of 65 to 70/degree/. Each well has an S-curve well program and is assigned a 100-ft cylindrical diameter course. A simulated drilling program is fed into a computer to make sure the proposed course does not come within 25 ft of any other well bore. Production procedures are outlined along with a discussion of auxiliary equipment.