Drilling fluid waste management in drilling for oil and gas wells

Abstract

Drilling operation produces two major wastes which are produced water and drilling waste. The drilling waste must be properly managed to ensure no impact to the environment and human. The environmental and human effects of the exposure to drilling waste are discussed in the paper. Different type of drilling fluids has different composition, which influence the environmental impact of the drilling fluid. Due to the potential impact to environment and human, there are regulations by the host government and international conventions for drilling waste management. Generally, oil based drilling fluid is not permitted for offshore disposal and drill cuttings require treatment before disposal. However, water based drilling fluid is allowed for disposal. Synthetic based drilling fluid is preferred due to its technical performance and minimum environmental effects. Main regulations related to environmental and waste management in Malaysia is Environmental Quality Act and Exclusive Economic Zone Act. There are three options of drilling waste disposal, which are offshore disposal, onshore disposal and drill cutting re-injections. Offshore disposal is limited by the regulations while onshore disposal can give additional liability at the disposal site. Drill cuttings re-injection can be a good option of disposal, with zero discharge to the site. However, not all formation is feasible for the re-injection.