_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 35615, “Flexible Coiled Tubing Implementation for Subsea Hydrate Remediation: Campos Basin Field Application, ” by Alina F. Rocha, PRIO; Kirk Gardiner, Paradigm Flow Services; and Matheus D. Bezerra, PRIO, et al. The paper has not been peer-reviewed. Copyright 2025 Offshore Technology Conference. _ This paper presents the successful deployment and results obtained from flexible coiled tubing (FCT) technology applied to an oil-producing well of the Frade field in the Campos Basin of Brazil. The success of the technology allowed re-establishment of well production to approximately 4, 300 BOPD, representing an increase of 9%, proving the viability of FCT in mature fields. Introduction When depressurization, inert gas bullheading, fluid displacement, and chemicals are unsuccessful for hydrate-blockage removal, mechanical techniques become necessary. However, for scenarios in which conventional steel capillary or coiled tubing (CT) cannot be used, alternative types of CT technologies must be employed. One such technology is a flexible composite CT, which, because of its materials, can handle challenging geometries and short-radius pipe bends and can reach significant distances owing to its ability to more-easily acquire neutral buoyancy while inside a pipeline. The complete paper aims to present the successful floating production, storage, and offloading vessel (FPSO) -based deployment of the FCT in the Frade deepwater field for the removal of a challenging hydrate blockage with sand content in one of the field’s production lines. The Frade field’s FPSO features a turret-mooring system, which led to additional challenges for the operation in comparison with those presented by a spread-mooring-system FPSO. The removal of the hydrate blockage would allow the return of Well A, which has already faced hydrate issues in the past and restricted production because of high sand content in production fluid. Frade Field Subsea Layout The field is 120 km offshore and is considered a mature oil field. Production commenced in 2009 and peaked in 2011. At present, the field uses 12 horizontal production wells employing gas lift, complemented by three vertical water-injection wells to sustain reservoir pressure. The subsea system consists of one water-injection flow loop, three gas lift flow loops, one gas import and export flowline, and six flexible production loops, with each loop supporting two production wells. Each branch of a production loop is dedicated to transporting individual production from a single well. The production flowlines (PFLs) are equipped with pigging isolation valves (PIVs) to isolate flowlines as needed. Each well connects to a subsea sled through a flexible production jumper. The subsea layout offers significant operational flexibility, allowing simultaneous production from two wells through a single production line when required. Well A is connected to the FPSO by PFL-A, the flowline affected by hydrate blockage. FCT Operation Well A is connected to the FPSO by a production line of 5, 500 m. After unplanned shutdown, transient pressure and temperature conditions entered the hydrate envelope and the blockage was confirmed. Several attempts have been executed to mitigate the blockage, including deliquification and hot oil circulation, but were unsuccessful.
Chris Carpenter (Mon,) studied this question.