Patent ID: 11879335
Assignee: CANOPUS DRILLING SOLUTIONS HOLDING B.V.
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 22:
23. A steerable sub for use in a directional drilling system, connectable at a downhole end thereof to a drill bit of the system, and at another end thereof to a tubular drill string of the system, comprising:
a sub fluid inlet port, fluidly connectable to a supply channel through the tubular drill string, to receive from the supply channel a stream of drilling fluid mixed with abrasive particles from the supply channel when the sub is connected to the drill string, and
a sub fluid outlet port, fluidly connectable to the bit fluid inlet port, to pass to the drill bit said stream when the sub is connected to the drill bit,
a modulation unit configured to cause a variation of a concentration of abrasive particles along stream portions of the stream received from the supply channel, the modulation unit being fluidly connected to the sub fluid inlet port, downstream thereof, the modulation unit comprising:
a first channel having a first flow resistance to the drilling fluid mixed with abrasive particles, a first inlet, and a first outlet fluidly connected to the sub fluid outlet port,
a second channel arranged in parallel to the first channel, having a second flow resistance to the drilling fluid mixed with abrasive particles, a second inlet, and a second outlet fluidly connected to the sub fluid outlet port,
a particle deflection device arranged at a location along the stream between the sub fluid inlet port and the first and second inlets, comprising one or more actuators connectable to a control unit,, wherein the particle deflection device is configured to periodically,
during a first time period, deflect a first majority of all abrasive particles received from the supply channel through the sub fluid inlet port into the first inlet, and
during a second time period following the first time period, deflect a second majority of all abrasive particles in the stream received from the supply channel through the sub fluid inlet port into the second inlet,, wherein the first and second channel are embodied such that a difference between the first flow resistance and the second flow resistance results in a velocity difference between said first majority of abrasive particles passing through said first channel and said second majority of abrasive particles passing through said second channel,, wherein said velocity difference is such that in a combination section downstream of the first and second outlets, the first and second majority, together with any of said drilling fluid passed into the first and second channel during the first and second time period, respectively, are combined into one of said stream portions, and minorities of abrasive particles not being deflected, together with any drilling fluid passed into the first and second channel during the second and first time period, respectively, into a subsequent one of said stream portions.