Action: Bury drill cuttings in the seabed rather than leaving them on the seabed surface
Key messagesRead our guidance on Key messages before continuing
- We found no studies that evaluated the effects of burying drill cuttings in the seabed rather than leaving them on the seabed surface on subtidal benthic invertebrate populations.
‘We found no studies’ means that we have not yet found any studies that have directly evaluated this intervention during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.
Routine oil and gas drilling activities can impact subtidal invertebrate seabed communities due to the production of drill cuttings. Drill cuttings consist of the fragments of rock that are removed as each oil or gas well is drilled. The drill cuttings are usually discharged onto the seafloor in the vicinity of the platforms to form a cuttings pile, but are often contaminated with drilling fluids, oil and chemical additives which can leach and pollute the sediments. Drill cuttings can also smother and bury organisms under their weight (Henry et al. 2017). Burying drill cuttings deep inside the sediment, a process, referred to as “cuttings re-injection” or “drill cuttings sub-surface injection” (Gumarov et al. 2014; Melton et al. 2000, 2004; Shadizadeh et al. 2011), rather than depositing them on the surface of the sediment, can potentially reduce the level of threat occurring for surface subtidal benthic invertebrates and those living inside the sediments at shallow depths. Evidence related to alternative means of disposing drill cuttings are summarised under “Threat: Energy production and mining – Dispose of drill cuttings on land rather than on the seabed”, and those related to stopping their disposal under “Cease or prohibit the deposit of drill cuttings on the seabed”.
Gumarov S.M., Shokanov T.A., Simmons S., Anokhin V.V., Benelkadi S. & Ji L. (2014) Drill cuttings re-injection well design and completion: Best practices and lessons learned. Society of Petroleum Engineers.
Henry L.A., Harries D., Kingston P. & Roberts J.M. (2017) Historic scale and persistence of drill cuttings impacts on North Sea benthos. Marine Environmental Research, 129, 219–228.
Melton H.R., Smith J.P., Mairs H.L., Bernier R.F., Garland E., Glickman A.H., Jones F.V., Ray J.P., Thomas D. & Campbell J.A. (2004) Environmental aspects of the use and disposal of non-aqueous drilling fluids associated with offshore oil & gas operations. In: SPE International Conference on Health, Safety, and Environment in Oil and Gas Exploration and Production. Society of Petroleum Engineers.
Melton H.R., Smith J.P., Martin C.R., Nedwed T.J., Mairs H.L. & Raught D.L. (2000) Offshore discharge of drilling fluids and cuttings–a scientific perspective on public policy. In Rio Oil and Gas Conference. Rio de Janeiro, Brazil.
Shadizadeh S.R., Majidaie S. & Zoveidavianpoor M. (2011) Investigation of drill cuttings reinjection: Environmental management in Iranian Ahwaz Oilfield. Petroleum Science and Technology, 29, 1093–1103.