Commissioning and Operational History of Nkossa II LPG FSO

Abstract

Summary In the mid-1990s, our client realized that their recent offshore find would yield viable liquefied-petroleum-gas (LPG) content. With the proposed field located more than 20 nautical miles offshore from an underdeveloped area, the option of exploitation on site was identified. Oil floating storage/offloading (FSO) units, usually adaptations of existing oil tankers, were already an established alternative to piping product ashore at that time. Therefore, tenders were invited for the provision of an LPG FSO unit. Any party tendering for this task would be covering new ground because this installation would be among the first of its kind. In particular, the physical properties of LPG demand different handling systems and techniques compared to oil. In tendering, we drew from the diverse marine enterprises within our group. We also engaged a partner specialized in offshore solutions. We had access to existing LPG tonnage of suitable capacity and our own yard for conversion work. We also had a competent technical support structure and potential within our personnel base for operational requirements. As with any new project, once tender requirements were met and accepted, evolution occurred. This evolution is of course not limited to the period leading up to commissioning but has continued through to the present. It is often the case that delivery of a specialized service holds a narrow spectrum of interest. However, it is our hope that this project, although relatively specialized, may also have value for any concern engaged in offshore storage and offloading. By this time, we have operated the unit for almost 15 years and can share some valuable experience.