Abstract: A downhole tool assembly for use in a drilling string includes a motor, a flow head, and a flow restrictor. The flow head is coupled to the motor and comprises a plurality of ports permitting fluid communication therethrough. The flow restrictor is in fluid communication with the flow head and comprises a plurality of ports permitting fluid communication therethrough. The flow restrictor is stationary with respect to the flow head, which rotates. As the flow head rotates, one or more of the plurality of ports of the flow head enters 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 constrained to a cyclic, polyrhythmic pattern optionally including at least one interval where the fluid flow is substantially blocked by the flow restrictor.

Abstract: 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.

Abstract: A downhole tool assembly for use in a drilling string includes a motor, a flow head, and a flow restrictor. The flow head is coupled to the motor and comprises a plurality of ports permitting fluid communication therethrough. The flow restrictor is in fluid communication with the flow head and comprises a plurality of ports permitting fluid communication therethrough. The flow restrictor is stationary with respect to the flow head, which rotates. As the flow head rotates, one or more of the plurality of ports of the flow head enters 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 constrained to a cyclic, polyrhythmic pattern optionally including at least one interval where the fluid flow is substantially blocked by the flow restrictor.

Abstract: 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.

Abstract: 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.