Microwave Heating: A Feasible Alternative for Drilled Cuttings Drying in Offshore Environments

Abstract

Abstract Drilled cuttings contaminated by Non Aqueous Fluids (NAF's) are a waste from oil well drilling activities. Over the past twenty years, studies have been conducted in order to assess the effects that these contaminated cuttings have on the environment. In Brazil, the environmental offshore discharge threshold for synthetic base is 6.9 % in mass. Microwave shows itself as a promising technology to remove the organic phase of these drill cuttings. This paper presents microwave heating technique as a new method for the treatment of contaminated drill cuttings. For this purpose, it was developed a batch microwave oven with capacity up to 6 kW. In experimental testing the mass input was 6 kg and the microwave oven was airtight. Microwave cuttings remediation was investigated for three different power inputs (3, 4 and 6 kW) at 0.50, 0.60 and 0.70 kWh/kg and for the specific energies ranging from 0.20 to 0.70 kWh/kg at 3 kW. The moisture content in a rehydration was also studied in cutting drying. The process can remediate the cuttings to below 2%, using the specific energy of 0.60 kWh/kg. The cutting drying by microwave heating is more efficient at low powers input. When cuttings that had already been dried were rehydrated and dried a second time it was observed that the smaller the amount of water content the better was the secondary removal of n-paraffin was.