Wellbore safety valve

Claim 2

A fail-safe system for bringing a well under control comprising: well pipe extending from the earth''s surface to a subsurface earth strata; a retrievable plug assembly located in the well pipe below the surface, a plug member and seat in the assembly, said plug member being spaced from the seat and arranged to engage the seat in sealing relationship to close off the well pipe; means for retaining the plug member in its spaced position from the plug seat so that the plug member does not normally engage the plug seat; means for releasing the plug member from the retaining means including electrical energy means connected with the releasing means, wherein the releasing means is adapted to function in response to the electrical energy means; means at the surface for monitoring fluid flow conditions; and means responsive to said monitoring means for controlling the electrical energy means.

Claim 3

The system of claim 1 wherein the releasing means is an electromagnet, the deenergization of which releases the plug member from the retaining means.

Claim 4

The system of claim 1 wherein the releasing means is adapted to be responsive to acoustical energy.

Claim 5

The apparatus of claim 1 wherein the assembly is located in a housing and includes housing retrieval means attached to the upper end of the housing.

Claim 6

The apparatus of claim 4 including annular seal means between the housing and well pipe for providing a fluid tight seal between the housing exterior and the interior wall of the well pipe.

Claim 7

The apparatus of claim 1 wherein the retaining means includes a section adapted to separate in response to the releasing means.

Claim 8

The apparatus of claim 1 wherein said releasing means includes an explosive charge which is detonated in response to the operation of the electrical energy means, and wherein the retaining means comprises a retaining member adapted to separate upon detonation of the explosive charge.

Claim 9

The apparatus of claim 1 wherein the retaining means includes a low melting point wire and wherein the releasing means includes electrical means for heating the low melting point wire above its melting point.

Claim 10

The apparatus of claim 1 wherein the retaining means includes a plastic coated acid dissovable retaining member and the releasing means comprises an encapsulated acid surrounding the plastic coated portion of the retaining member.

Claim 11

The apparatus of claim 9 including a resistance heating coil connected with the electrical energy means and located adjacent the plastic coated portion of the retaining member, whereiN electrical energy supplied to the resistance heating coil acts to melt the plastic coated on the dissovable retaining member.

Claim 12

A fail-safe system for sealing a wellbore having well pipe therein extending from the surface of the earth to an earth formation comprising: housing means detachably fixed to the interior wall of the well pipe, said housing having a fluids flow channel therethrough; a seal assembly located in the housing including a plug member positioned in the fluids flow channel and a plug seat which is annular and defines an opening which is part of the fluids flow channel; means normally urging said plug member to engage said plug seat; means for restraining the plug member from engaging said plug seat; and means for releasing the restraining means from the plug member; said releasing means including an acoustical energy responsive means and means responsive to the acoustical energy responsive means for disengaging the plug member from the restraining means.

Claim 13

A fail-safe system for sealing a wellbore having well pipe therein extending from the surface of the earth to an earth formation comprising: housing means detachably fixed to the interior wall of the well pipe, said housing having a fluids flow channel therethrough; a seal assembly located in the housing including a plug member positioned in the fluids flow channel and a plug seat which is annular and defines an opening which is part of the fluids flow channel; means normally urging said plug member to engage said plug seat; means for restraining the plug member from engaging said plug seat; and means for releasing the restraining means from the plug member; said releasing means including an acoustical energy responsive means and means responsive to the acoustical energy responsive means for disengaging the plug member from the restraining means.

Claim 14

A fail-safe system for bringing a well under control having well pipe extending downwardly from the surface of the earth into subsurface formations, comprising: housing means detachably fixed to the interior wall of the well pipe, said housing having a fluids flow channel therethrough; a seal assembly in the housing including an annular seat positioned in the fluids flow channel and a plug member sized for mating reception with said seat to form a closure in said fluids flow channel; means for releasably holding said plug member in a position spaced from said seat; means for normally urging sad plug into a sealing position with said seat; and means for releasing said holding means said releasing means including an electrically operated means which is arranged to release said plug upon the absence of electrical energy and an auxilliary releasing system which operates said releasing means in response to an acoustical energy transmission.

Claim 15

A fail-safe system for bringing a well under control having well pipe extending downwardly from the surface of the earth into subsurface formations, comprising: housing means detachably fixed to the interior wall of the well pipe, said housing having a fluids flow channel therethrough; a seal assembly in the housing including an annular seat positioned in the fluids flow channel and a plug member sized for mating reception with said seat to form a closure in said fluids flow channel; means for releasably holding said plug member in a position spaced from said seat; means for normally urging sad plug into a sealing position with said seat; and means for releasing said holding means said releasing means including an electrically operated means which is arranged to release said plug upon the absence of electrical energy and an auxilliary releasing system which operates said releasing means in response to an acoustical energy transmission.