Drilling Waste Management – Solutions that Optimise Drilling, Reduce Well Cost and Improve Environmental Performance

Abstract

This paper highlights the value associated with the thermal processing of drill cuttings offshore, at source, on an operational and economic basis for a single well drilling campaign. Treating materials at source eliminates the requirement to transport drilling wastes long distances onshore for treatment and/or disposal, significantly reducing logistics costs and the likelihood of safety and environmental incidents. The paper outlines a safe, efficient and reliable at source drilling waste management solution that increases operational efficiency, supports well cost reduction initiatives and exceeds regulatory requirements. It also demonstrates that mobilizing this solution as an onboard drill cuttings processing spread for a one- well drilling campaign is cost-effective. The paper draws on a detailed case study in which thermal drill cuttings processing technology was mobilized for a one-well drilling campaign on the Orlando field in the UK North Sea, under a contract between TWMA and the Licence Operator but managed by the Well Operator AGR Well Management (AGR). Using a process of thermal desorption, the solution allows the recovery of three elements from the drill cuttings: oil, water and solids. Recovered base oil, which retains its full original quality, can be reintroduced to the drilling mud system, and recovered water and solids can be safely dispersed on location as they are processed to well within UK environmental tolerances and regulatory requirements. Using the technology on the Orlando development well enabled a reduction in drilling waste handling and reduced downtime, due to the elimination of wait on weather, reducing rig non-productive time by allowing continuous drilling during adverse weather conditions. It also reduced handling, storage, offshore lifting and skip to shore vessel requirements, for the 17 ½" and 12 ½" sections, saving an estimated $640,000 in vessel costs alone (based on the market rates at that time). Thorough planning meant initial challenges relating to delivery of equipment was quickly mitigated and support from TWMA, in close co-operation with AGR and the operator, helped to reduce the operational time-table and costs. The drilling waste management operation was completed within time and on budget with zero Lost Time Incidents and zero loss of containment to the environment during operations.