Because of the short length and reduced weight of the IRJ, it can be picked up and installed in a single lift. This, in addition to other key design features, is a known differentiator over other commercial offerings. BOP running times were affected by as little as 8 h when incorporating the IRJ within the riser string. This included running the IRJ through the rotary table, installing the goosenecks and single MPD umbilical in the moonpool, performing function tests on the IRJ, and pressure testing the MPD goosenecks and flowlines, which can take 3 to 4 times longer using other commercial systems.
MPD operations commenced with drilling the 12 1/4-in hole section. The section was successfully drilled to a total depth of 18,445 ft [5,622 m],
a 5,302-ft [1,616-m] interval in which 36 MPD connections were made while holding constant bottomhole pressure. The entire interval was drilled with a single run of the @balance Speed sealed rotating system, a key performance contributor of the system given 208-h installation time at speeds between 120 to 180 rpm. Following a smooth trip out of hole, the MPD system was taken offline so that the operator could begin logging operations.
DNV GL recently revised its classification rules for MPD systems and introduced two new class notations—DRILL(MPD) and DRILL(MPD READY). Stena Drilling is the first drilling contractor to receive the notation DRILL(MPD) for its harsh-environment drillship Stena Carron. The certification process assessed all the components’ roles within the system in an operational environment as well as the effect on existing systems onboard, ensuring that the isolation, redundancy, and safety systems met the standards of the new notation.