Subsurface Cuttings Injection: Technical Challenges and Opportunities

The progression of new and remote field development, including arctic and deepwater, inherently increases the volume of cuttings and waste generated from drilling, completion and production operations. The economic and environmental impact of this waste management including transportation, treatment and final disposal is considerable and can be drastically decreased through subsurface cuttings and waste injection. This environmentally friendly disposal solution provides an effective and practical way to minimize associated health, safety and environmental risks by eliminating transportation needs and potential accidents, and therefore reducing the long-term project environmental footprint. Nowadays, cuttings injection is considered a proven technology for the final disposal of drilling waste through subsurface injection into an engineered subsurface strata or formation where the injected waste is safely contained for permanent storage. The logistical constrains of transporting large volumes of produced waste to the final disposal site poses many challenges in large-scale field development, where the most cost-effective solution is often to drill a dedicated injector well, process and inject all the produced waste at the single cuttings injection site. An application of comprehensive fracture-mapping techniques is a major step in ensuring that the target formation will be suitable to accommodate all waste volume injected. Fracture mapping the waste domain complexities represents valuable information, not only in the overall planning of drilling operations, but in the fundamental and invaluable need to provide sound engineering and assurance for the waste subsurface containment. This papers describe the driving factors and opportunities for implementing cuttings injection in one of the largest and complex development projects in the northern part of Caspian Sea where ecologically sound drilling, stringent environmental regulations and “zero discharge” policy commitment are critical for the success of the drilling operations and overall field development.