Vol. 226 No. 12

Rig Floor Equipment

Positive pressure transfer system moves cuttings

Drill cuttings storage and transportation is an operational and financial challenge in offshore and environmentally sensitive areas, and it is now a critical element in well planning and execution. Regulations and good environmental protection have brought innovation in “total containment” of drilling waste. Brandt’s solution for cuttings transport and storage is its new “Freeflow” System.

The positive pressure transfer system offers a unique innovation for the efficient transportation and storage of drill cuttings. The heart of the system is a single air conveyor, PLC-based control system and non-plugging Slider Storage Vessels. The concept is a totally enclosed containment system that requires very little intervention and far fewer crane lifts. It is safe, flexible, efficient and environmentally conscious.

Brandt’s Freeflow contains unique features to ensure reliability and consistent performance.

Brandt’s air conveyor contains unique features to ensure reliability and consistent performance. The chisel profile base minimizes bridging, and the integral 14-in. screw ensures accurate feed control, as cuttings entering the line are metered. The screw generates a series of aerated slugs, improving pressure control and achieving a consistent flow pattern. These controlled slugs minimize pressure fluctuations, ensuring safe pressure control and low exit velocities. A single air conveyor can move more than 80 tons per hour of dried solids. In addition, the unit was designed to transfer solids 164 ft (50 m) vertically as required for inter-field transfers.

The operator-friendly PLC-based control system offers unprecedented levels of control, both in the manual and automatic modes. The operator can monitor the system and set parameters using the 10-in. display. The air conveyor discharge cycle can be set by weight or time. The screw speed is controlled by the pressure sensor on the discharge side of the unit.

Another unique feature is the Pipewatch system. Part of the control is a system that monitors line pressures and automatically adds air when needed to eliminate blockage. The system continually monitors pressures at specific intervals along the line. When pressure in the line increases, a timed amount of air is injected into the line at a specific point to flush any solids and prevent blockage. In addition, the system features data acquisition, allowing recording and historical analysis.

The unique design of the Slider tank prevents the bridging associated with conventional conical bottom bulk storage tanks. The base allows the introduction of a flat bottom tank that removes the danger of bridging. The discharge is ensured through the inclusion of the Slider ram and the use of an integrated, variable speed-controlled, 14-in. discharge screw. The tank features diverter valves and load cells within the compact frame design. This allows for easy installation of multiple tanks. Each tank is filled and emptied in a safe, controlled fashion. The dimensional design of the slider tank allows for easy transportation by road, and removes the requirement to modify a dedicated supply vessel for transportation offshore.