Defining a Path Towards Successful Low Cost Marginal Field Subsea Developments – An Overview

Abstract

Subsea oil and gas developments in the Grand Banks region, offshore Eastern Canada, require mitigation techniques to protect against iceberg keel interactions. For example, untrenched infield flowlines incorporate weak link systems designed to fail in the event of flowline snag to protect upstream and downstram assets. Even with these systems, the assumption that any iceberg contact equates to flowline failure means that flowline lengths in excess of approximately 10 km require trenching to meet safety target levels. Furthermore, all subsea wells to date have been installed in excavated drill centers to avoid contact with gouging icebergs. Based on current design practices, these mitigation measures are cost prohibitive and limit the potential for the development of marginal fields. This paper addresses conventional practice to protect against iceberg interaction and proposes alternative solutions that maintain safety, while reducing costs significantly.