It is estimated that the UKCS produces between 50,000 to 80,000 tonnes wet weight of oily drill cuttings annually. With the implementation of OSPAR Decision 92, and given current offshore technology, it is no longer possible to discharge cleaned oily cuttings to sea. Increasingly stringent legislation also makes it likely that cuttings derived using water-based muds will not be discharged to sea in the future.
Although several commercially available treatment processes can remove oil from oil based mud (OBM) cuttings, there are few satisfactory outlets for the residual solid material most of which currently goes to landfill. In light of the legislative changes, increased focus on duty of care, and commercial considerations, viable alternatives are being sought for the recycling and reuse of large volumes of material from future drilling programs.
This paper examines possible options for converting drill cuttings into reusable secondary products and discusses the advantages and disadvantages of each option when considered against the criteria of environmental impact, technical risk, logistics, liability and cost. Examples of the research and pilot trials currently being undertaken to assess the feasibility of these options is discussed, as well as work being carried out to establish the variation in chemical composition of cuttings in the UKCS, since tolerance to the variation in the chemical characteristics of drill cuttings is a major issue for most of the end uses.