Shale shaker motors are generally three-phase induction motors that are explosion proof, having NEMA design B or similar characteristics (Table 1). The number of magnetic poles in a shale shaker motor can be four (1800 rpm synchronous shaft speed at 60 Hz), six (1200 rpm), or two (3600 rpm). The motor should have independent, third-party markings indicating its suitability in explosive or potentially explosive environments. It is recommended that these motors be suitable for Class I, Division 1, Groups C and D, and Group IIB atmospheres. The motor also should have the proper operating temperature or code designation for the anticipated ambient temperature.
Continuous-duty electric motors are an integral part of a drillings rig’s solids-control and processing systems. Centrifugal pumps that feed hydrocyclones, circulate mud for mixing, and transfer mud to and from reserve and also into the trip tank are powered by electric motors. Shale shakers, mud cleaners, centrifuges, and pit agitators are also driven by electric motors.
Cuttings dryers are sometimes referred to as secondary drying of cuttings.Cuttings dryer is the most widely used technology for safely handling drilling waste. Drilled cuttings with associated fluid from the rig solids-control equipment have been passed over a second drying shaker for a number of years. The recovery of oil-based drilling fluid coupled with a 10 – 25% reduction in disposal volume is usually easily justified and has become standard procedure in areas where so-called pitless drilling or closed loop systems are the norm. Generally, the secondary drying shaker is a four-panel screening device running at 7.0 – 7.3 G’s at the screen surface. Drilled cuttings from a drying shaker typically test between 8 and 12% base oil (NAF) by wet weight. This retention-oncuttings (ROC) figure is significantly higher than the current minimum allowed for offshore discharge in the United States and, increasingly, elsewhere around the world. Accordingly, there has been increased interest in lowering the ROC figure by the use of different types of drying equipment.
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.