UniTong Combined Tong for Drilling Operations

Abstract

Abstract This paper gives a short introduction to the first field tested, multi power tong capable of handling drill pipe, tubing and casing using the same tong and crew. The tong is called UniTong and lets one operator handle all tubulars from 2 7/8" to 22" casing, without the need for dedicated casing or tubing tongs. What makes this tong unique is its capability to be parked concentrically on the well centre. Drilling, tripping and casing operations can be performed through the centre of the UniTong. No movement to and from the rotary table is required, as with traditional equipment, and associated crane operations for equipment movement to and from the rig floor are greatly reduced. The UniTong is completely remotely operated, eliminating manual handling by rig crews; operations are conducted from the safety of the driller's cabin. This has a significant impact on well site safety. Incorporated as an integrated part of the tool is a mudbucket, dope applicator and thread wash system. These applications are also remote operated and can be automatically sequenced. To switch between drillpipe, tubing and casing modes only the clamp houses have to be replaced, in three intervals 2 7/8"-9 ½", 9 ½"-16" and 18"-22". The closed concentric design of the tong makes it very robust and durable. All clamp forces are absorbed into the drive ring and the metal fatigue normally experienced with traditional casing/ tubing and iron roughneck tongs is eliminated. The tong can exert extremely high torques of up to 150 000 ft/lbs (210 000Nm). Existing casing tongs lack this high torque capacity and as a result have difficulty handling dopeless connections, crucial to the zero-pollution goal set by a number of oil companies. In 2005, the UniTong design was awarded the prestigious "Woelfels Best Mechanical Engineering Achivement Award" in Houston, Texas.