Capex reduction and project management complexity are at the top of the list of the main drivers for subsea flowlines, together with the water depth and the opex increases. Rigid risers and flowlines remain the main solutions used for offshore fields but the new market conditions are forcing the industry to increase the attention towards more cost-competitive solutions over the current CRA-based ones.
This paper describes the main performances and characteristics of a fluorinated polymer, already used in offshore flexible risers, as potential use for internal lining of rigid flowlines.
The scope of the paper is: i) to provide the evidence on the positive impact on CAPEX and project management complexity brought by the lining solution, ii) to provide data on the flow assurance advantages and iii) to provide an insight on the positive impact on the OPEX reduction and on the operational complexity improvements.
The paper is composed of three sections. A first section will provide a mechanical analysis of the performance of the polymer in respect of the main technical requirements of the lining solution. Going through the existing track record in offshore, the main chemical and permeation resistance characteristics of the polymer are shown. The second section focuses on a cost analysis. A first Capex analysis, mainly based on material cost comparison, shows the advantage of using this lining solution over the CRA based ones. Then, starting from an overview of the main surface properties of the polymer proposed, this paper will also show wax-deposition test data and a drag reduction simulation analysis. The drag analysis was initiated from real service conditions, considering different types of service for the flowlines, and was done in comparison with existing metallic solutions. This analysis then provides an idea of the OPEX reduction and the operational advantages of the use of plastic lined pipelines vs metallic solutions.
The third section completes the paper with some results from real in-field tests, which were performed onshore, and also with a real track-record on a new lining technology, used offshore and based on the polymer here proposed.
Conclusions show CAPEX and OPEX advantages, the improvement in the project management, with the possibility to increase the level of the local content (where requested) of the project and then also the flow assurance advantages and the OPEX reduction associated to the lining solution.