The use of rigid pipelines in underwater engineering projects is based on their proven robustness and extensive history of use in the oil and gas industry. However, market limitations and challenging schedules are offensive agents to this type of architecture that need to be mitigated and overcome to add flexibility to the project and optimize resources utilization.
One of the main limiting factors of the rigid pipeline-based underwater architecture is the connection with subsea equipment. Typically, this connection is made through rigid jumpers between a Pipeline End Termination (PLET) installed at the end of the flowlines and the connection point with the subsea equipment, usually a Subsea Christmas Tree or subsea equipment, such as manifolds or boosting units. In order for these jumpers to be properly connected, it is necessary for the pipeline and equipment to be already in place and for metrology to be performed: their positions must be measured, and tolerances determined before the jumper can be manufactured and installed.
As a common practice during the interconnection phase of the rigid pipe-based subsea architecture, it is necessary to perform precommissioning steps of the rigid pipeline, including flooding and hydrostatic testing, followed by metrology between the PLET and the Subsea Christmas Tree hubs. The manufacturing process of the rigid jumper that connects the rigid pipeline to the subsea equipment, including the final welding and testing is only performed after this metrology process. This takes a certain amount of time with direct impact on the critical path for the readiness of the subsea system of the project.
