COLD FLOW IN LONG-DISTANCE SUBSEA PIPELINES

Abstract

As the world?s appetite for energy continues to grow, oil and gas developments are moving to ever deeper subsea environments, thereby causing hydrates-related issues to become a growing concern for the industry. Hydrates blockages, beyond the safety risk they represent, result in time-consuming and costly mitigation and remediation operations. Most hydrate experiences found in the literature, and the corresponding prevention and remediation strategies, concern subsea pipelines. This work relates a novel technology for hydrate mitigation in subsea pipelines. This is the cold flow technology. A detailed review of the cold flow technology, its main component equipment, the concepts by different organizations on the technology, as well as the advantages and disadvantages of each proposal has been done. A qualitative research method is used, which is suitable when exploring a new phenomenon. Six cases of different technologies were chosen which include: chemical inhibition (THIs and LDHIs), direct electrical heating system and three potential emerging cold flow technology concepts for ensuring flow assurance in long pipelines. The technical, environmental and economical evaluations of the different technologies have been done. In order to obtain information on these cases, observation and documental studies (archives) were chosen as research methods. These methods however do not give me all the needed information about the various cases and this is a weakness of the results.Cold flow technology was compared with the conventional technology currently used for tackling hydrate and wax problems. It was found out that the cold flow technology offers a more robust means of eliminating the problem in a cost and environmentally effective manner especially over long distances greater than 200 kilometers. The lessons learned from this experience are presented here and are currently being used as a basis for improving operation guidelines and hydrates prevention strategies for deepwater transportation pipelines.