Descontaminação de cascalhos de perfuração utilizando um secador micro-ondas semi-industrial em regime contínuo

Abstract

In the process of drilling oil wells, rocks fragments are generated and called drill cuttings. They are brought to the surface through the drilling fluid. When the drill reaches the oil reservoir, the rocks fragments generated are called reservoir drill cuttings, because they have intragranular oil. Drill cuttings and drilling fluids must be separated in order to reuse the drilling fluid and remove contaminants in drill cuttings so that it can be disposed. The cuttings dryer is responsible for the decontamination of these drill cuttings, allowing their disposal as long as the residual contents of synthetic bases (olefin and n-paraffins) are below 6.9%, by mass, according to Brazilian environmental legislation. Microwave drying has proved to be an excellent alternative as a drill cuttings dryer, reaching levels of organic base below 1%. In addition, microwave treatment has been widely used in the remediation of soils petroleumcontaminated, showing its possible application in remediation of reservoir drill cuttings. In this work, a semi-industrial prototype of continuous microwave dryer was developed for the decontamination of drill cuttings, and were evaluated the remediation of reservoir drill cuttings in a bench scale. The prototype was tested under real operating conditions, using mass flow rates between 250-750 kg/h, synthetic base content between 7.5-12.5% and using offshore drill cuttings, evaporite and reservoir drill cuttings. In the bench scale was evaluated the remediation of reservoir drill cuttings with water-based fluid and synthetic-based fluid. The prototype was able to reduce the residual content to levels below 0.1%, with low specific energy. It has also been shown to be effective in decontamination of evaporite and promising in remediation of reservoir drill cuttings. The remediation of reservoir drill cuttings in the bench scale showed that temperature and specific energy are important parameters for the treatment of this type of cuttings and the technology is able to remediation of reservoir drill cuttings.