Environmental implications of offshore oil and gas decommissioning options: an eco-efficiency assessment approach

With the tremendous rise of aged offshore oil and gas (O&G) facilities, the world is on the horizon of a decommissioning dilemma. In addition to higher cost consumption, decommissioning offshore O&G platforms is an energy-intensive process and results in the production of huge waste on dry land. Few studies have been undertaken to assess and compare the environmental impacts of various decommissioning options, but economic barriers and data gaps have confronted the virtue of these studies. A holistic framework to assess the environmental and economic implications and identify the best decommissioning option is the need of the hour which can give clarity of selection to stakeholders of the offshore O&G decommissioning industry. This study aims to develop an eco-efficiency framework, by integrating environmental life cycle assessment and life cycle costing, to assess the environmental and economic impacts of the decommissioning process of offshore O&G platforms. A comparative study of four decommissioning options is carried out to determine the best decommissioning option for a specific offshore O&G platform. The study indicated that the use of vessels in the decommissioning process is the major contributor to the environmental impacts and costs. This framework helps the decision-makers to select cost-effective options which can reduce the environmental impacts and result in the reduction in resource exploitation.