The spool/jumper method (see Figure A.24) uses a spool/jumper to bridge the distance (gap) between the end of the flowline and its connection point on the subsea facility, e.g. a subsea tree, PGB, manifold or riser base.
This method is also often employed to link adjacent subsea facilities, e.g. a subsea tree to a nearby subsea manifold. Spools and jumpers can be used in both horizontal and vertical connection configurations, and may be made up using either diver-assisted or diverless techniques.
Source: API RP 17A, Design and Operation of Subsea Production Systems—General Requirements and Recommendations, Fourth Edition, Reaffirmed 2011. Global Standards