Technical and Economical Comparison of Subsea Active Heating Technologies

Abstract

Active heating of subsea flowlines is an attractive solution for facing flow assurance issues related to always going deeper and longer, as well as more complex fluids and critical wellhead flowing conditions (pressure, temperature, flowrate) prone to pour point issues, hydrates and/or wax appearance risk. Over the last 15 years, several active heating technologies have been developed and operated in order to significantly help solve flow assurance issues from the subsea wellheads up to the surface support facilities. These technologies have demonstrated to be very different in their design and operability (use of hot water, direct or indirect electrical heating) but also in their efficiency and cost. In parallel with the development of heated flexible pipe designated IPB (Integrated Production Bundle) already used for field development in West Africa and Brazil as well as a rigid heated pipe-in-pipe technology, both using electrical heat trace cables, Technip has been involved in the design, construction and installation on several projects of all active heating technologies. Based on this extensive knowledge and track-record, this paper describes and compares the working principle as well as the advantages and drawbacks of the different active heating technologies. This paper also identifies their limitations with regards to field application, i.e. length and water depth based on their actual development status. On the basis of different generic case studies (shallow long tie-back, shallow in-field development, deep water tie-back and ultra-deep water in-field development), this paper finally reviews all the potential benefits the different active heating technologies can bring to a project and includes an economical comparison of these technologies.