Sustainable Recycling of Oil-Contaminated Drilling Cuttings as Oil Well Cementing Additive

With the increasing exploitation of conventional oil/gas and large-scale shale gas development, the effective management of oil-contaminated solid waste from formations has become a major challenge. Conventional treatment methods for oil-contaminated drill cuttings (OCDCs) have several limitations, including high equipment costs, substantial energy consumption, and difficulties in controlling secondary pollution. This study proposes an innovative in situ recycling approach that repurposes the OCDC as a cement-based oil-contaminated cutting additive (OCCA), enabling low-energy consumption treatment at the contamination source and achieving waste valorization within a green closed loop system. Although unprocessed OCDC degrades cement integrity, amphiphilic surface modification of OCCA prevents agglomeration and enhances both dispersion and interfacial bonding, thereby improving the mechanical performance of the cement. Moreover, the use of OCCA significantly reduces the free heavy metal ion content in the set cement, effectively mitigating potential long-term environmental risks such as groundwater contamination from the cement sheath. The developed OCCA demonstrates excellent compatibility with cementing operations, fulfilling both mechanical and environmental requirements, and shows great potential in practical engineering applications.