Down hole motors and methods for their operation
AssigneeDen Norske Stats Oljeselskap A.S.
InventorsEgil Sunde, Per Olaf Haughom
Life of this patent
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Abstract
A down hole motor assembly includes a hydraulic drive portion, a drill bit operatively connected to the drive portion and a disengage mechanism (11) arranged to disengage drive to the drill bit. The disengage mechanism (11) is arranged to be actuated by supplying drilling fluid to the drive portion at a flow rate which is greater than the flow rate at which fluid is supplied to run the drive portion during normal drilling. The disengage mechanism is arranged to be re-set so that drive is reconnected to the drill bit when the fluid supply to the drive portion is shut off.
Claims26
A method of operating a down hole motor assembly which comprises a hydraulic drive portion, a drill bit operatively connected to the drive portion, and a disengage mechanism arranged to disengage drive to the drill bit, the method comprising:
- supplying fluid to the drive portion at a first fluid flow rate selected to drive the drive portion and consequently the drill bit;
- supplying fluid at a second flow rate which is greater than the first flow rate, thereby actuating the disengage mechanism so that the drill bit ceases to be rotated;
- and
- supplying fluid at a third flow rate which is significantly lower than the first flow rate, thereby resetting the disengage mechanism so that drive is reconnected to the drill bit.
A down hole motor assembly, comprising:
- a hydraulic drive portion,
- a drill bit operatively connected to the drive portion, and
- a disengage mechanism arranged to disengage drive to the drill bit;
- the disengage mechanism being arranged to be actuated by supplying fluid to the drive portion at a second flow rate which is greater than a first flow rate at which fluid is supplied to run the drive portion during normal drilling;
- the disengage mechanism being arranged to be re-set so that drive is reconnected to the drill bit when fluid is supplied to the drive portion at a third flow rate which is significantly lower than the first flow rate.
Dependencies are inferred from the claim text.