The past decade has shown a fast growing subsea production market tending to complete factories on the sea floor involving ever more complicated infrastructure and increasing size and weight components to be installed. The water depth of this market typically ranges between 1000 and 3000m. This new subsea market triggers a need for increased deep water lowering capacity to enable safe, fast and efficient installation of this infrastructure.
The authors’ company has gained extensive experience in the field of deep water installation over the past 15 years, ranging from complex mooring foundations to the installation of large subsea production units in up to 3000m water depth. This experience is used and further deployed in the specification of new and higher capacity deep water lowering systems for recent and upcoming investments.
The paper will share a number of the contractor’s considerations with respect to a state-of-the-art deep water lowering system meeting the needs of today’s subsea production market. The paper will address the challenges associated with the various stages of deep water installation, choices made in type of ropes (steel versus fiber), pros and cons of various floater types that can be used as an installation platform and the need for and effect of passive or active heave compensation.