Patent ID: 6343655
Filing Date: 2002-02-05
Classification: E21B

Abstract:
A method of intervention at a number of distinct intervention points spread across the sea bed using a free end of one riser originating from a semi-submersible platform designed for producing oil from a deposit, said method comprising:tethering the platform to immobilize the platform in a position floating over the deposit; installing the riser connecting the floating platform to the sea bed for intervention at a first intervention point; carrying out an intervention at the first intervention point; disengaging the free end of the riser from the first intervention point, while keeping the free end of the riser submerged; moving the free end of the riser with respect to the sea bed towards a second intervention point, while keeping the floating platform immobilized in said position floating over the deposit; and carrying out an intervention at the second intervention point; wherein said moving of the free end of the riser comprises installing at least one fixed point on the sea bed beforehand, installing a hauling mechanism between the free end of the riser and each of said at least one fixed point, and hauling the bottom end of the riser using the hauling mechanism connected to each of said at least one fixed point, so as to cause the free end to move with respect to the sea bed towards the second intervention point.