Swivel and Kelly Valve Maintenance

The swivel and kelly valve connect the high-pressure mud system to the drill string while allowing the string to rotate. The swivel bearing carries the weight of the kelly, the tool joint and the suspended drill string while sealing against fluid pressure. The kelly valve isolates the standpipe pressure when the crew needs to make or break connections. Both items are easy to overlook because they sit between other high-profile components, but both are essential to safe and efficient drilling. Swivel maintenance begins with bearing condition. The bearing should be checked for play, noise and heat before each round trip. A swivel with bearing play will allow the kelly to wobble, causing premature wear on the kelly saver sub and the tool joint. Heat indicates inadequate lubrication or a failing seal. The swivel should be drained, flushed and refilled with the correct grade of oil at the interval the manufacturer prescribes. That oil should be sampled for water and metal content during major services. A swivel that leaks mud into the bearing housing will contaminate the lubricant and destroy the bearing before the next bit run. Kelly valve maintenance focuses on sealing and operation. The valve should open and close without sticking, seal without leaking at working pressure, and lock in the open or closed position when the handle is secured. A kelly valve that leaks during a connection forces the crew to bleed pressure from the standpipe manually, adding time and exposure to high-pressure fluid. The valve seat and the seal should be replaced on a schedule tied to drilling hours and pressure cycles, not to the convenience of the next connection. Housekeeping and rig-floor discipline reduce damage to both components. The kelly should never be dropped onto the master bushing, and the swivel should never be used as a lifting point for equipment it was not designed to carry. The crew should inspect the kelly safety clamps, the torque transmission bolts and the wear bushings with the same frequency as the BOP controls. When swivel and kelly maintenance records are kept with the rest of the mechanical checks, the driller can see the readiness of the entire top drive system in one review in rig equipment inspection checklist. ← Back to rigs.work