CPC E21B 47/09 (2013.01) [E21B 34/066 (2013.01); E21B 34/14 (2013.01); E21B 47/04 (2013.01); G01V 3/26 (2013.01)] | 20 Claims |
1. A system for locating a casing collar, said system comprising:
a drill pipe sub-assembly which includes a drill pipe segment and a detection apparatus disposed at a portion of the drill pipe segment, the drill pipe segment comprising a wall and an interior portion defined within the wall;
said detection apparatus comprising:
a bypass port disposed in the wall and in fluid communication with the interior portion;
an annular sleeve which directs fluid through the bypass port and into the interior portion;
an actuator which opens and closes the bypass port; and
two magnetized coils which interact to generate an electromagnetic field;
wherein the actuator closes the bypass port in response to a predetermined voltage generated by the magnetized coils when the coils displace past a casing collar;
a weight loss detection device which detects a loss of weight in the drill pipe segment after closing of the bypass port; and
a depth determination device which determines a depth of the casing collar, based on the detected loss of weight.
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