Matrix PDC coring bit for medium-hard and above homogeneous formations

Abstract

The invention provides a matrix PDC coring bit for medium-hard and above homogeneous formations. Cutting PDC clad sheets and limiting impact-resistant PDC clad sheets are arranged at the upper end ofthe crown part of the bit at intervals; the limiting impact-resistant PDC clad sheets are two columnar PDC clad sheets and comprise a limiting impact-resistant PDC clad sheet a and a limiting impact-resistant PDC clad sheet b; the height of the limiting impact-resistant PDC clad sheet a is 2-3 mm lower than the height of the cutting PDC clad sheets in the axial direction, the height of the limiting impact-resistant PDC clad sheet b is 1 mm lower than the height of the limiting impact-resistant PDC clad sheet a, and the limiting impact-resistant PDC clad sheet a and the limiting impact-resistant PDC clad sheet b are arranged in a staggered mode. On the one hand, the limiting impact-resistant PDC clad sheets limit the depth of the cutting PDC clad sheets cut into the formations, so that thebit is subjected to small rock resistance, and stick-slip vibration of the bit is reduced; and on the other hand, a circumferential shearing effect can be generated on residual rocks on the working surface, so that the rocks are broken and loosened, the rotary drilling resistance is smaller, adverse working conditions are reduced, the service life of the bit is prolonged, and the drilling speed isincreased.

Description

technical field [0001] The invention relates to the field of geological drilling, in particular to a matrix PDC core drill bit for medium-hard and above homogeneous formations. Background technique [0002] In the field of geological drilling, when the PDC core bit drills in the medium hard and above homogeneous formation, under the action of the drill pressure, the PDC composite sheet is pressed into the formation, and the formation is cut and drilled under the rotation of the drill pipe. Sometimes in order to increase the drilling speed, the drilling pressure is increased, so that the PDC composite sheet is pressed into the formation too deeply, resulting in a large reaction force on the drill bit, which will cause the drill bit to pause for a short time, while the drill pipe continues to rotate , accumulating torque, when the torque reaches a certain level, the torque transmitted to the drill bit is enough to break the rock, then the drill bit accelerates to rotate, and a...

AI Technical Summary

Problems solved by technology

The stick-slip vibration of the drill bit, longitudinal bounce and residual rock on the working surface will cause great damage to other structures such as the PDC composite sheet and the support body, causing abnormal wear of the brittle PDC composite sheet, thereby reducing the quality of the PDC core bit. life span

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