Abstract
The first major deepwater oil discovery was made in Ghana during 2007. Since then over 50 deepwater wells have been drilled by various operators using Low Toxicity Oil Based drilling fluids. Discharge of drilled cuttings to the ocean with residual oil on cuttings has been permitted in Ghana under the current regulatory regime. Current offshore cuttings drier technology will reduce residual oil on cuttings to low levels prior to discharge but not eliminate it completely.
Many other offshore drilling areas around the world operate a ‘zero discharge’ approach where no oil contaminated cuttings are permitted to be discharged overboard. In this case the cuttings are contained offshore before being shipped onshore for treatment. The oil is then removed and reused using thermal desorption or equivalent technology, the clean water is discharged and remaining clean cuttings are utilised in land fill sites or in some cases building products. These ‘Skip and ship’ methods require offshore cuttings handling equipment, a supply chain involving marine vessels and trucks for onshore cuttings transport. Most importantly it requires a specialised onshore treatment facility that will completely remove any residual oil on cuttings prior to disposal of the clean dry cuttings.
This paper will describe the component parts of a skip and ship method and how it would operate in a new deepwater oil province. It describes in detail how one service provider pre-emptively set up an onshore cuttings treatment facility in Ghana in readiness for future skip and ship operations. The detailed technical operation of the facility is described and technical and political learnings are offered.
