Magnetic hammer with vibration caused by relative rotation of magnetic arrays

摘要

Drilling apparatus having a rotating drillstring with axial vibration of the drill head is disclosed. Vibrational apparatus (70) with interactive magnetic arrays (75, 76) is positioned as part of the drillstring to provide the vibration. There is a first assembly with a first magnetic array, and a second assembly with a second magnetic array. The first and second arrays react in response to relative rotation between the arrays to cause relative shuttling of the arrays and their respective supporting assemblies. One of the assemblies moves synchronously in rotation with the drillstring when the drillstring is rotated.