Currently many operators are making a concentrated effort to reduce the amount of synthetic based drilling fluids or muds (SBM) discharged offshore. In order to achieve these goals many new devices are being developed such as the vertical basket centrifuge. Vertical basket centrifuges have been used in the mining industries for years to dry water-wet coal and other processed minerals. These centrifuges have proven successful in the reduction of synthetic based drilling fluid on cuttings (SOC) for drilling operations worldwide (Fig. 1).
This paper will describe the typical cuttings drying equipment suite, layout, and performance of the vertical basket centrifuge. The SBM recovery package involves a two part process: a vertical basket centrifuge for drying of the SBM drill cuttings and the use of a high speed decanting centrifuge for reconditioning and re-use of the recovered SBM drilling fluid.
In most instances the rig's shale shakers are unable to consistently produce dry drill cuttings in relation to the amount of synthetic on cuttings (SOC). Field data has shown as much as 50 to 70 percent reductions in the percent by weight SOC between shale shakers and vertical basket centrifuges samples, thereby effectively reducing the amount of synthetic-based drilling fluid that would have otherwise been discharged overboard.