Decommissioning Using Reverse Reeling

With numerous offshore facilities coming to the end of their operational life cycle, operators are looking at options to extend the life of their aging assets or where no viable alternative exists, complete decommissioning of the field. Decommissioning in Australia involves the removal of all surface and subsurface infrastructure used to support the oil and gas industry and is a requirement under the Offshore Petroleum and Greenhouse Gas Storage Act 2006, where titleholders are responsible for the full costs and safe removal of all offshore infrastructure, (NOPSEMA, 2020). It is estimated that over the next few decades the majority of the oil and gas fields in Australia will be decommissioned and to align with the legislative act, operators are already taking steps to understand and address the decommissioning costs, requirements and methodologies, and in some instances have already started the process of retiring and removing their facilities. The scale of the challenge is vast, the Centre of Decommissioning Australia, (CODA, 2020) has conducted a review on behalf of a number of the Australian operators and reported that in Australia alone, 6660km of export and infield pipelines and 1500km of umbilicals, excluding spools, flexible jumpers, risers, flying leads etc. have been installed and will be required to be removed or left in-situ with the agreement of the Australian legislative body, NOPSEMA. The cost associated with the decommissioning of the offshore assets is significant with government estimates of up to $60bn AUD, (Wood Mackenzie, 2020).