Comparative Assessment of Environmental Impacts Associated with the Decommissioning of Fixed offshore Platforms

This paper presents the assessment of environmental impacts associated with the decommissioning of offshore fixed platforms, using two approaches of Life Cycle Assessment (LCA). Decommissioning is the process which the operator of an offshore oil or natural gas installation carries out when it is no longer needed for its current purpose. While there has been an increased environmental awareness in recent years,there is a lack in quantitative assessments approaches pertaining to environmental impacts due to offshore structures decommissioning in South East Asia. In this
research, LCA is performed to quantify the environmental impacts in terms of energy consumption and gaseous emissions (CO2, SO2 and NOx) related to two decommissioning options, which are complete removal and conversion of a platform
jacket to artificial reef (rigs to reef). The platform chosen for this study is a fixed jacket platform located in the shallow water region of Malaysia. The two tools employed in are Process-based LCA and Economic Input Output (EIO)-LCA method. The results showed that the impacts can be contradictory for the impact evaluation on the two decommissioning options using the different approaches. The probable reasons are deliberated in the conclusion section. The findings of this study may serve as a basic framework for future assessment of environmental impacts regarding offshore decommissioning activities in Malaysia.