JOIDES Resolution Tour 1985–2005
JOIDES Resolution Drilling Operations
For several decades, engineers in ocean drilling have supported science by developing advanced drilling and coring systems. The engineers also have modified systems borrowed from the energy exploration and mining industries. Industry, in turn, has adapted many ocean drilling innovations.
The technology of ocean drilling and the science it supports have greatly advanced during the last 30 years. A drill ship such as the JOIDES Resolution, with its sophisticated drilling tools and ability to deploy almost six miles of drill string, enables scientific ocean drilling to enter a new phase in which earth processes can be more precisely examined, analyzed and measured than ever before. The ship was built in 1978 in Halifax, Nova Scotia. In 1984, ODP converted it into a floating scientific research center. An ice-strengthened hull allows it to drill in high-latitude seas.
Dynamic Positioning System
A positioning system, supported by 12 powerful thrusters, uses computers to maintain the ship over a specific location while drilling in water depths up to 8,200 meters (5 miles). The ship can suspend as much as 9,150 meters of pipe to obtain core samples. The 400-ton heave compensator keeps the drill string stable relative to the ocean floor.
Coring Operations
While on site, drilling continues 24 hours a day. Drilling takes place on the rig floor, a platform about four feet above the bridge deck in the center of the ship.
The pipe racker, located aft of the drill floor stores the pipe. A length of drill pipe—called a long joint—measures 9.5 meters. The crew makes a stand of drill pipe by assembling three joints at a time.
On the rig floor, a mechanical device called an iron roughneck makes up the drill string by connecting stands of pipe.
The crew lowers the assembled drill pipe from the drill floor through the moon pool a shaft that measures 7 meters across and extends through the bottom of the ship.
After the crew lowers the drill string to the seafloor, coring operations begin. The drill crew lowers core barrels through the drill pipe. The core barrels receive and contain the core material cut by the drill bit. On average, the core barrel takes about 90 minutes to complete one round trip. When it returns to the rig floor, technicians recover the long cylinder of sediment or rock.
Deep holes often require several changes of drill bits. Each change of drill bit requires that the entire drill string be brought up, stand by stand, until the bit can be changed at the bottom of the string. With a new bit in place, the crew must reassemble the string before it reenters the hole.
A reentry cone, lowered through the moon pool and set on the seafloor, enables the drilling equipment to reenter the hole several times. A sophisticated system of scanning sonar equipment and an underwater television camera guides the drill string back into the hole.