Implementation of Direct Electric Heating as Part of the Hydrate Control and Management System

摘要

The use of Direct Electrical Heating (DEH) for sub-sea pipelines has become a method for hydrate and wax management control either by itself, or as part of other hydrate management and control techniques. The method is based on resistive heating of the steel pipe by leading electrical AC current in the flowline.rnDEH has so far only been used in the North Sea, with the first system installed 8 years ago. To date 6 installations are operational with another 4 being implemented.rnSimulations are carried out to determine whether or not the DEH technology is suitable for the Ichthys Gas Field development.rnDetails of 5 insulated sub-sea flow lines were provided as a basis forrnthe investigation:rn1. To extend the no touch time required after a shutdown, i.e. tornavoid depressurization of sub sea system, by keeping flowlinesrnabove hydrate formation temperature (this is considered the mainrnobjective of the study).rn2.To warm up a cold flowline from seabed temperature to the targetrntemperature above hydrate formation and keep it at thisrntemperature indefinitely.rn3.To melt hydrates after prolonged shutdown.rnFor both these scenarios, the electric power data for the DEH system are determined. Results from the simulations were compared with results from (OLGA) simulations concerning cool-down scenarios.rnThe thermal configurations for the pipelines and the operational conditions have been the governing parameters to provide DEH data.rnFor the application of DEH this method has also been compared with more traditional flow assurance systems regarding topside equipment, and there are obvious advantages concerning required volume and weight.