CPC E21B 34/105 (2013.01) [E21B 2200/05 (2020.05)] | 18 Claims |
1. A safety valve usable in a wellbore, the safety valve comprising:
a piston configured for displacing a flow tube;
a flapper valve;
the flow tube for opening the flapper valve;
a plurality of outer magnets attached to the piston, at least some of the plurality of outer magnets having a non-alternating polarity with respect to one or more adjacent outer magnets of the plurality of outer magnets; and
a plurality of inner magnets attached to the flow tube, at least some of the plurality of inner magnets having the non-alternating polarity with respect to one or more adjacent inner magnets of the plurality of inner magnets such that a first force to decouple the plurality of inner magnets from the plurality of outer magnets is higher than a second force to recouple the plurality of inner magnets to the plurality of outer magnets, wherein:
the plurality of outer magnets comprises a first outer magnet of a first size, a second outer magnet of a second size, and a third outer magnet of a third size;
the plurality of inner magnets comprises a first inner magnet of the first size, a second inner magnet of the second size, and a third inner magnet of the third size; and
the first size is different from the second size or from the third size.
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