Floating offshore drilling platform - with two crabs on derrick and turntable for underwater storage of drill tubes

摘要

Offshore drilling platform floats on legs which enter into open containers and rest on disc springs and spherical compressed air containers. Derrick has two cantilevers, each with a crab for handling the drill string. Turntable is used to suspend up to 108 m long drill tubes in the water below the platform. Hollow submerged rings joining the bottom end of the legs can be used to pump contra-rotating streams of water around them so as to steady the platform and derrick. This speeds up the drilling operations by using 108 m long sections of drill tubes instead of 27 m. Its stabilising system, amplified by compressed air jets permits drilling operations to continue even in heavy seas. Low centre of gravity has a stabilising effect.