| 摘要 |
In one embodiment, the invention provides a drilling assembly comprising a motor, a reaming stabilizer and a drill bit. The motor is adapted to be attached to a drill string, the motor includes a drive shaft with a mandrel mounted at the bottom end of the shaft . The reaming stabilizer is attached to the shaft of the motor by the mandrel, so that the stabilizer may be rotatably driven by the motor. The drill bit is attached to the stabilizer t o be rotatably driven by the stabilizer. The stabilizer is sized so that the overall length of the drilling assembly is increased by a maximum of about 16 inches. Greater lengths may reduce motor bearing life, adversely affect the steering of the tool or result in drive shaft breakage with consequent loss of the drill bit and stabilizer in the hole.
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