Abstract: A dual phase riser flotation system contains a number of passive phase buoyancy modules of syntactic foam contained within an outer skin, and a number of active phase buoyancy modules which are similar to air canisters in that they may be inflated or deflated as required to provide levels of buoyancy. The passive phase buoyancy modules may contain tubes filled with air, a compressed gas such as nitrogen, or evacuated to provide additional buoyancy. Charge and discharge valves connect gas flow lines to a manifold system serving the active phase buoyancy modules.

Abstract: An acoustic/shock wave attenuating assembly comprised of porous screens forms an enclosure filled with a suitable pressure wave attenuating medium or material having fluid characteristics. This basic configuration can be suspended or held in place by a rigid structure. When the pressure attenuating medium is a liquid, the attenuating assembly is provided with a lining for containment. Multiple attenuating assemblies can be employed, with adjacent attenuating assemblies separated by a small gap. The pressure attenuating medium may be a liquid, a gas emulsion, an aqueous foam, or a gel (with or without entrained gas). Alternatively, solid particulates having bulk mechanical properties of a fluid may be employed as the pressure wave attenuating medium and may have an adhesive or the like resisting relative movement between particulates to simulate viscous effects.

Abstract: An acoustic/shock wave attenuating assembly comprised of porous screens forms an enclosure filled with a suitable pressure wave attenuating medium or material having fluid characteristics. This basic configuration can be suspended or held in place by a rigid structure. When the pressure attenuating medium is a liquid, the attenuating assembly is provided with a lining for containment. Multiple attenuating assemblies can be employed, with adjacent attenuating assemblies separated by a small gap. The pressure attenuating medium may be a liquid, a gas emulsion, an aqueous foam, or a gel (with or without entrained gas). Alternatively, solid particulates having bulk mechanical properties of a fluid may be employed as the pressure wave attenuating medium and may have an adhesive or the like resisting relative movement between particulates to simulate viscous effects.