Method for efficiently recycling water based drilling fluids has been developed. This recycling is conducted in a way beneficial both for the drilling fluid supplier and the operator. Contaminated fluid (slop) is brought back onshore for treatment and reusable fluids from the slop treatment are brought back into the drilling fluids.
Cutting boxes are the primary method of transporting waste drilling fluid and cuttings to shore around the world. Cuttings boxes were developed as an easy method of collecting and transporting cuttings given the weight restrictions of offshore cranes on earlier drilling rigs. Cutting boxes are typically placed near the solids control equipment, where cuttings can be moved relatively short distances and collected in the box. When a Cutting boxes gets full, it is removed and an empty Cutting boxes is shuffled into position. When a sufficient number of full Cutting boxes are ready, they are backloaded onto a workboat and returned to shore. Empty Cutting boxes from the dock facility replace the returned cuttings boxes.
Vacuum transfer systems provide an alternative to augers. The initial applications were on jackups, primarily in the Gulf of Mexico, where the cramped areas required multiple conveyors to get around the legs and other obstacles. It was also easy to close the discharge chute, making a sump to collect the cuttings that is suitable for the vacuum nozzle.
Screw Conveyors ( Augers ) are commonly used to move drilled cuttings and associated fluid. They can be arranged to collect the cuttings (usually relatively dry oil-based cuttings) from the individual pieces of solids control equipment and convey them to another area of the drilling rig where they are used to load cuttings boxes (skips). The standard screw conveyor is composed of an auger or screw housed in a flanged, U-shaped trough with bolt-on covers. It is powered by an electric motor and equipped with an appropriate gearbox. The motor must be sized to provide enough horsepower and torque to permit the transport of cuttings at a rate at least equal to the maximum rate at which they are delivered to the screw. The feed and discharge ends are fitted with flanges and ports to allow the cuttings to flow into and out of the conveyor without plugging. For multiple screw sections, hanger bearings are used to support the ends of the screw sections where they are joined. Operating parameters such as loading, housing enclosures, and length of the section are all considered in determining the required bearing type.