Closing the Loop on Oil-Based Drill Cuttings: A Critical Review of Treatment, Resource Recovery, Reuse, and Scale-Up

Oil-based drill cuttings (OBDC) are variable, multiphase wastes whose composition influences their treatment response and the quality of downstream products. This critical review compares major OBDC treatment and management routes using a material-stream framework. Published studies are examined for feed characteristics, treatment conditions and endpoints, recovered and residual streams, product quality, downstream uses, and evidence of industrial operation. Thermal and thermomechanical separation have the most extensive industrial record, including multi-year, multi-unit operations. Recent cyclone treatment adds a 69 h continuous industrial campaign, while solvent extraction, hydrothermal treatment, pyrolysis, plasma treatment, and biological processes are supported mainly by laboratory, bench, or limited field studies. The comparison shows that oil removal, material recovery, product qualification, and documented reuse describe different stages of waste management. Recovered oil requires assessment against its intended use, while treated solids need engineering and environmental qualification for the receiving application. Energy use, reagents, wastewater, off-gas, maintenance, storage, transport, and receiver capacity also affect industrial performance. The review identifies the operating and reporting evidence needed to compare technologies and supports integrated planning from feed handling through treatment, product acceptance, and final outlets.