In the previous article we have been acquainted with the very basics of the power system of the offshore drilling rig. And now, let us have a look at another fundamental system of any rig - the hoisting system. It is also one of the most important systems without which no drilling could be done.
The system serves a purpose of lifting the whole drill stem in drilled hole and out of it in the process of making a new well and lowering the casing down. This system itself is made of several elements, namely the substructure, the derrick (in some cases there can be the mast instead) and the drawworks, then the crown block and the traveling block equipped with the hook, and of course the drilling line.
The substructure of any rig is specifically designed and constructed to be able to effectively support the weight of the derrick taken together with the rotary table and the load of the drill stem when it is either suspended or standing in the derrick. Note that the substructure shall provide the support to the casing string during the time when they run the casing.