Abstract
Decommissioning of offshore installations is increasingly becoming a crucial issue to the Oil and Gas industry as most assets within the sector are approaching the end of their economic life. Common decommissioning options include complete removal, partial removal and re-use. Inappropriate selection of a decommissioning option can have severe financial, environmental, health and safety consequences. The best available option is usually determined by taking into account technical feasibility, economic viability, consumption of natural resources and, health, safety and environmental impact.
Net Present Value (NPV) analysis is often used to assess the economics of decommissioning options. However, an economic analysis based on purely financial criteria is not in itself adequate for valid decision making. Non-financial factors which are not reducible to monetary values should be identified and incorporated into the overall economic analysis. Weighted Evaluation (WE) is a technique used to assess the feasibility of non-financial factors. In this paper, a hybrid of NPV analysis and WE technique has been developed to assess the economic and technical viability of decommissioning options. The hybrid technique is used in a case study to assess and compare the impact of different decommissioning options on a selected Oil and Gas platform. An appropriate decommissioning option with minimum combined financial, environmental, health and safety impact is determined.
