DOWNHOLE DRILLING TOOL

摘要

A directional drilling tool includes a housing defining a central cavity for enabling the transmission of drilling fluid through the drill string. A motor contained in the housing includes a rotor-stator assembly, and produces eccentric motion of the rotor. An inverter or shock absorbing assembly disposed along the housing upstream from the motor functions to expend and contract the central cavity in response to fluid pressure changes produced by the drilling fluid flow. A valve assembly, comprising a multi-port flow head that rotates under influence of the motor and a multi-port flow restrictor, creates a varying pattern of pressure spikes in the drilling fluid as the ports of the flow head move into and out of alignment with the ports of the flow restrictor, which in turn induces a percussive effect and axial movement in the drill string.

主权项

1. A drilling tool assembly for use in a drill string, the drilling tool assembly comprising:
a motor comprising an eccentrically-driven rotor; a flow head comprising a plurality of ports permitting fluid communication therethrough, the flow head being coupled to a rotor of the motor to be driven thereby in eccentric rotational motion; a flow restrictor in fluid communication with the flow head, the flow restrictor comprising a plurality of ports permitting fluid communication therethrough, the flow restrictor being stationary with respect to the rotational motion of the flow head, wherein rotation of the flow head with respect to the flow restrictor causes one or more of the plurality of ports of the flow head to enter into and out of alignment with one or more of the plurality of ports of the flow restrictor such that fluid flow through the ports of the flow head and the flow restrictor is varied in an irregular pattern, the irregular pattern comprising a pattern in which an orientation of the flow head at a defined position in a cycle of the rotor is different between consecutive cycles of the rotor.