Decommissioning Offshore Installations’ Environmental Evaluation Using Life Cycle Analysis

In many years to come, the number of offshore oil and gas installations to be decommissioned around the world will increase as the platforms will cease production or may reach the end of their service design life. Malaysia in particular has about 300 offshore installations in four regions; Peninsular Malaysia, Sarawak, Sabah, and the Malaysia-Thailand Joint Authority (MTJA), whereby 48% out of the total installations have exceeded their 25 years of service design life. However, there is insufficient information regarding the decommissioning of offshore facilities in Malaysia. Hence, measures in terms of cost, environmental, technicality, political, social, safety, and other relevant measures should be studied earlier on before planning a decommissioning. In this study, the author will focus on the environmental aspects to offshore decommissioning options with the aid of Life Cycle Analysis (LCA). The LCA methods used to compare and assess the environmental impacts of decommissioning options in this study will be process-based method and EIO-LCA method. It has to be ensured that the platforms to be compared and assessed are of the similar profile, type, region and water depths. Moreover, the environmental variables concerned in this area of study include the total energy consumptions and gaseous emissions such as carbon dioxide (CO2), sulphur dioxide (SO2), and nitrogen oxides (NOx). Based on the comparison done in the author’s case study, a suitable decommissioning option with the least impact on the environment will be chosen and relevant suggestions will be recommended.