| CPC E21B 23/01 (2013.01) [E21B 47/09 (2013.01)] | 15 Claims |

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1. A positioning and orientating apparatus for branch well, comprising:
an orientating coupling shaft (1), with a central flow channel (11) provided therein for flow of drilling fluid;
a hydraulic cylinder (2), arranged at a downstream end of the orientating coupling shaft (1), with a guiding sleeve (3) fixedly connected to an upper end of the hydraulic cylinder (2);
a setting unit, arranged on the hydraulic cylinder (2), and comprising an anchoring mechanism (4) and a sealing mechanism (5) arranged at a lower end of the anchoring mechanism (4);
a setting actuation unit (6), comprising a sealing cylinder (62) arranged around the orientating coupling shaft (1), a piston (63) arranged inside the sealing cylinder (62), and a force transmitting cylinder (64) arranged around the guiding sleeve (3), wherein an upper end of the force transmitting cylinder extends upwards to be fixedly connected to the piston (63), a sealing chamber (65) in communication with the central flow channel (11) is formed within the sealing cylinder (62), and the piston (63) is configured to drive the force transmitting cylinder (64) to move downwards when a pressure of the drilling fluid reaches a first pressure, in order to drive the anchoring mechanism (4) to be anchored securely to an inner wall of a wellbore, and drive the sealing mechanism (5) to form a seal with the inner wall of the wellbore; and
a releasing unit (7), connected to a lower end of the orientating coupling shaft (1), and comprising a pressure-bearing cylinder (71) fixedly connected to the lower end of the orientating coupling shaft (1), an elastic claw (72) arranged around the pressure-bearing cylinder (71), and a ball seat (73) fixedly connected to a lower end of the pressure-bearing cylinder (71), wherein an inner wall of the guiding sleeve (3) is provided with a slot (31) which engages with the elastic claw (72) by snap fitting in an initial state, and the ball seat (73) is configured to receive a ball (9) dropped from a wellhead to build up pressure, so that the elastic claw (72) is separated from the slot (31) by lifting up the releasing unit (7) when the pressure of the drilling fluid reaches a second pressure, thus completing a releasing procedure,
wherein the first pressure is less than the second pressure.
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