Microwave Drying of Reservoir Drilled Cuttings

Abstract

The disposal of drill cuttings in offshore operations has become a critical issue considering the increasing restrictions imposed by environmental legislation. When reservoir formations are reached in the drilling phase, cuttings contaminated with both drilling fluid and crude oil return to surface. Due to the presence of oil, which may contain toxic and non-biodegradable pollutants like polyaromatic hydrocarbons, specific discharde restrictions are usually applied. In this scope, microwave drying is proposed as a treatment method for drill cuttings contaminated with petroleum. In other words, this work aims to show how microwave drying technology can be a promising alternative in the treatment of drill cuttings originated from oil and gas reservoirs. First, a set of published results that reinforce the use of this technology in the drying of cuttings is presented. Then, a set of experiments that evaluated the efficiency of microwave drying of drill cuttings contaminated with petroleum of different API gravity was carried out. As expected, the microwave treatment of cuttings contaminated with light gravity oil presented lower residual contents than the heavy oil ones once light oil samples contain lighter hydrocarbons, which present lower boiling temperatures. Additionally, the remediation of oil-contaminated cuttings was promising, showing that it was possible to reach residual oil contents under 1% in mass after applying specific energies around 1.15 kWh/kg.