Pre-Metrology in Subsea Rigid Jumpers As a Key to Anticipating First Oil in the Pre-Sal Scenario

Abstract The use of rigid pipes in subsea production systems has been a preferred solution due to their typical robustness and extensive history. A key limiting factor has been the jumper connecting the pipelines to the subsea equipment, whose construction typically requires detailed metrology between the equipment once installed. This work presents solutions that removed the jumper from the critical path of the project, anticipating the start of production or injection. Supporting the PLET over a suction pile that allows the controlled landing and locking of the PLET in all its degrees of freedom is the first step to allow the anticipation of information about relative distance between hubs of the equipment to be interconnected. With strict dimensional control of the structures, it is possible to indirectly determine the final position and inclination of the hub even before installation. Offshore pre-metrology was performed with 3D scanning between the suction pile and the Well Christmas Tree - WCT. This process generates the required data to start the fabrication of the jumper. One of the main limiting points of submarine architecture based on rigid pipelines is the connection with subsea equipment. Typically, the pipe and equipment must be installed beforehand, and detailed metrology must be performed. By using a suction pile that allows the controlled landing and locking of the PLET in all its degrees of freedom, metrology was performed before the installation of the pipeline and the PLET itself. The suction pile is easily installed through various installation methods and vessels, reducing the need for expensive resources such as large installation vessels and decoupling their schedule. By installing the suction pile first, metrology was performed using the WCT and the suction pile as reference, allowing the jumper itself to be manufactured before the pipe is laid, what is referred to as pre-metrology. The offshore pre-metrology constituted a significant contribution to the anticipation of the first oil schedule as well as the ramp-up of a newly arrived Production Unit in an oil and gas Field in development of production. Typical comparisons showed a 10-to-15-day reduction in time between the conclusion of pipeline pre-commissioning and tie-in operations. The use of the solution of supporting the PLET of the rigid pipeline on a pre-installed foundation, restricting its degrees of freedom on the seabed, can be considered a good engineering option that allows the application of the pre-metrology solution and significant anticipation of the installation schedule of a subsea system development.