Patent ID: 6155748
Filing Date: 2000-12-05
Classification: E21B

Abstract:
An underwater riser system comprising:a) a riser;b) a plurality of passive flotation modules disposed along a longitudinal axis of the riser and coupled to the riser;c) a plurality of active flotation modules disposed along the longitudinal axis of the riser and coupled to the riser;d) a gas flow conduit;e) a charge valve connected to the gas flow conduit having a first port connected to the gas flow conduit to selectively allow flow therethrough;f) a manifold coupled circumferentially to the riser and having an inlet sealingly connected to a second port of the charge valve, the manifold also having at least one nipple engaging at least one active flotation module to allow flow thereto;g) a discharge valve conjoined with an outlet of the manifold.