Blowout Preventer Landing Assist Tool (BLAT)
The BLAT (Blowout Preventer Landing Assist Tool) is used to assist in landing a BOP (Blowout Preventer) onto a subsea wellhead. The BLAT is threaded onto 6 5/8" drill pipe (FH or XT-57 Threads). This can be changed per customer request. The BLAT is then lowered through the Telescopic Joint (TJ), until the BLAT's Anti-Torque Boss makes contact with the BLAT Transition Pup Joint (BTJ). The BTJ is bolted between the TJ and riser. The flanges shown at the ends of the BTJ but can be replaced with whatever riser joint connection method the customer uses. The drill pipe is then rotated about 4 turns Counter Clockwise (CCW), which causes the BLAT's load arms to extend and make contact with the BTJ's inner surface.
Tension is then applied to the drill pipe, which raises the BLAT until it's Load Supports make contact with the BTJ's Load Support Slots. More tension is applied to the drill pipe (2,000 kips SWL), which raises the BLAT, TJ, BTJ, Riser, and BOP. After the BOP has been sucessfully landed and locked onto the subsea wellhead, tension is then reduced on the drill pipe, which allows the BLAT's Anti-Torque Slots to re-land into the BTJ. The drill pipe is then rotated Clockwise (CW), which causes the BLAT Load Supports to retract. The BLAT is then pulled back through the BTJ and TJ, and retrieved.