Abstract: Apparatus is provided for introducing a consistent series of small and localized rotary impacts to a PDC bit during drilling, to improve PDC drill bit performance. Rotary impact supplements the nominal torque supplied by the rotary drive thereby avoiding lockup and potentially damaging energy storage in the drill string following windup, should the bit slow or hang up when drilling in difficult formations. The apparatus comprises a rotary hammer which is rotated about a bit shaft's anvil, preferably by a drilling fluid driven turbine. As the hammer rotates, potential energy is built up. When the hammer and anvil connect, the energy is released into the bit shaft and thus into the bit, increases its instantaneous torque and allows it to more effectively cut through difficult formations.

Abstract: An improved coiled tubing directional drilling method comprises: providing a bent housing which is rotatably coupled to the coiled tubing, rotating the drill bit, and rotating the bent housing. Apparatus for achieving the method comprises: a rotary connection between the coiled tubing and the bent housing and means for rotating the bent housing relative to the coiled tubing and to the drill bit. A fluid pressure-operated clutch enables alternate rotation and locking of the bent housing. Preferably, a first downhole motor rotates the drill bit and a second downhole motor rotates the bent housing through the clutch or alternately a speed reducer permits the bent housing to contra-rotate slowly under reactive torque developed by the rotating drilling bit.

Abstract: Apparatus is provided for introducing a consistent series of small and localized rotary impacts to a PDC bit during drilling, to improve PDC drill bit performance. Rotary impact supplements the nominal torque supplied by the rotary drive thereby avoiding lockup and potentially damaging energy storage in the drill string following windup, should the bit slow or hang up when drilling in difficult formations. The apparatus comprises a rotary hammer which is rotated about a bit shaft's anvil, preferably by a drilling fluid driven turbine. As the hammer rotates, potential energy is built up. When the hammer and anvil connect, the energy is released into the bit shaft and thus into the bit, increases its instantaneous torque and allows it to more effectively cut through difficult formations.

Abstract: An improved coiled tubing directional drilling method comprises: providing a bent housing which is rotatably coupled to the coiled tubing, rotating the drill bit, and rotating the bent housing. Apparatus for achieving the method comprises: a rotary connection between the coiled tubing and the bent housing and means for rotating the bent housing relative to the coiled tubing and to the drill bit. A fluid pressure-operated clutch enables alternate rotation and locking of the bent housing. Preferably, a first downhole motor rotates the drill bit and a second downhole motor rotates the bent housing through the clutch or alternately a speed reducer permits the bent housing to contra-rotate slowly under reactive torque developed by the rotating drilling bit.