Petroleum well tubing safety valve

Claim 2

A safety valve for incorporation in the flow path of petroleum issuing from a petroleum well through a tubing string comprising: a tubular housing forming a part of a petroleum well completion; means defining a circumferentially extending, annular seat in the throughbore of the housing, facing downwardly; a flapper; axle means on said flapper laterally offset from a diameter of the flapper; means mounting the axle means with respect to the housing so the flapper is movable between an open condition wherein the flapper is disposed generally parallel to the petRoleum flow path, below the annular seat and a closed condition wherein the flapper is seated against the annular seat, interrupting the petroleum flow path; spring means mounted in the housing, said spring means disposed to urge the flapper toward the seat; a tubular piston vertically slidably disposed in the throughbore of the housing so as to be disposed above the valve seat when the flapper is in a closed condition; means defining an upwardly facing surface on said piston; two circumferentially extending seal means disposed between and sealing with the housing and the piston, one above and one below said upwardly facing surface; fluid conduit means communicating through the housing to the ambit of the upwardly facing surface so that pressurized fluid may be admitted to bear against said upwardly facing surface to drive said piston downwardly; stop means in said housing and stop shoulder means on said piston abuttable with one another to limit downward travel of the piston; said piston including downwardly projecting stinger means engageable with the flapper as the piston is driven downwardly for forcing the flapper to an open condition; and downwardly facing surface means on the piston subject to pressure in the petroleum flow path for causing upward movement of the piston, withdrawing the stinger from forceable opening of the flapper so that the spring may close the flapper the upwardly facing surface being generally frustoconically curved; the throughbore radially adjacent the upwardly facing surface when the piston is uppermost being complementarily frustoconically curved; the fluid conduit means communicating with the throughbore intermediate the frustoconically curved portion of the throughbore and the valve further including a metal seal ring above and another below the communication of the fluid conduit means with the throughbore for sealing between the complementarily frustoconically curved surfaces of the piston and the housing.

Claim 3

The safety valve of claim 1 wherein said tubular housing is constituted by a well head part.

Claim 4

The safety valve of claim 1 wherein said tubular housing is constituted by a tubing bonnet.

Claim 5

The safety valve of claim 3 wherein the tubing bonnet is equipped for a multiple completion by having a plurality of side-by-side longitudinal throughbores, including said throughbore, provided at their upper ends with means for establishing a sealed relationship with respective bores of a christmas tree master valve and at their lower ends with means for establishing a sealed relationship with individual strings of tubing.

Claim 6

The safety valve of claim 1 wherein the tubular housing is constituted by tubular sub means incorporated in a tubing string between the ends of the tubing string.

Claim 7

The safety valve of claim 1 further including frangible a shear pin initially pinning the piston to the housing with the piston at such a lowered condition that the stinger holds the flapper nearly open, but the stop means on the piston and housing are not in abutment.

Claim 8

The safety valve of claim 1 wherein the stop means on the housing is constituted by a circumferentially extending, radially inwardly opening recess in the housing; and a snap ring received in the housing and projecting radially inwardly from the groove.

Claim 9

The safety valve of claim 1 wherein the spring means is constituted by a torsion spring including at least one leg disposed to bear against the flapper in such sense as to urge the flapper toward the seat and at least another leg disposed against the housing.

Claim 10

The safety valve of claim 8 wherein said torsion spring includes a curved intermediate portion looped around said axle means for retention.

Claim 11

A safety valve for incorporation in the flow path of petroleum issuing from a petroleum well through a tubing string comprising: a tubular housing forming a part of a petroleum well completion; means defining a circumferentially extending, annular seat in the throughbore of the housing, facing downwardly; a flapper; Axle means on said flapper laterally offset from a diameter of the flapper; means mounting the axle means with respect to the housing so the flapper is movable between an open condition wherein the flapper is disposed generally parallel to the petroleum flow path, below the annular seat and a closed condition wherein the flapper is seated against the annular seat; interrupting the petroleum flow path; spring means mounted in the housing, said spring means disposed to urge the flapper toward the seat; a tubular piston vertically slidably disposed in the throughbore of the housing so as to be disposed above the valve seat when the flapper is in a closed condition; means defining an upwardly facing surface on said piston; two circumferentially extending seal means disposed between and sealing with the housing and the piston, one above and one below said upwardly facing surface; fluid conduit means communicating through the housing to the ambit of the upwardly facing surface so that pressurized fluid may be admitted to bear against said upwardly facing surface to drive said piston downwardly; stop means in said housing and stop shoulder means on said piston abuttable with one another to limit downward travel of the piston; said piston including downwardly projecting stinger means engageable with the flapper as the piston is driven downwardly for forcing the flapper to an open condition; and downwardly facing surface means on the piston subject to pressure in the petroleum flow path for causing upward movement of the piston, withdrawing the stinger from forceable opening of the flapper so that the spring may close the flapper; said housing including means defining a circumferential downwardly facing ledge in said throughbore and means defining a circumferentially extending, radially inwardly opening groove subjacent the ledge; two arcuate retainers being received in the throughbore, against the ledge, the retainers each having one end engaging the corresponding end of the other; the opposite ends of the retainers having means defining recesses therein which open facing one another; the opposite ends of the axle means being received in the recesses; and a snap ring received in the inwardly open groove to hold the arcuate retainers in place, so that the ledge, groove, retainers and snap ring constitute said mounting means for the axle means.

Claim 12

A safety valve for incorporation in the flow path of petroleum issuing from a petroleum well through a tubing string comprising: a tubular housing forming a part of a petroleum well completion; means defining a circumferentially extending, annular seat in the throughbore of the housing, facing downwardly; a flapper; Axle means on said flapper laterally offset from a diameter of the flapper; means mounting the axle means with respect to the housing so the flapper is movable between an open condition wherein the flapper is disposed generally parallel to the petroleum flow path, below the annular seat and a closed condition wherein the flapper is seated against the annular seat; interrupting the petroleum flow path; spring means mounted in the housing, said spring means disposed to urge the flapper toward the seat; a tubular piston vertically slidably disposed in the throughbore of the housing so as to be disposed above the valve seat when the flapper is in a closed condition; means defining an upwardly facing surface on said piston; two circumferentially extending seal means disposed between and sealing with the housing and the piston, one above and one below said upwardly facing surface; fluid conduit means communicating through the housing to the ambit of the upwardly facing surface so that pressurized fluid may be admitted to bear against said upwardly facing surface to drive said piston downwardly; stop means in said housing and stop shoulder means on said piston abuttable with one another to limit downward travel of the piston; said piston including downwardly projecting stinger means engageable with the flapper as the piston is driven downwardly for forcing the flapper to an open condition; and downwardly facing surface means on the piston subject to pressure in the petroleum flow path for causing upward movement of the piston, withdrawing the stinger from forceable opening of the flapper so that the spring may close the flapper; said housing including means defining a circumferential downwardly facing ledge in said throughbore and means defining a circumferentially extending, radially inwardly opening groove subjacent the ledge; two arcuate retainers being received in the throughbore, against the ledge, the retainers each having one end engaging the corresponding end of the other; the opposite ends of the retainers having means defining recesses therein which open facing one another; the opposite ends of the axle means being received in the recesses; and a snap ring received in the inwardly open groove to hold the arcuate retainers in place, so that the ledge, groove, retainers and snap ring constitute said mounting means for the axle means.

Claim 13

A safety valve for incorporation in the flow path of petroleum issuing from a petroleum well through a tubing string comprising: a tubular housing forming a part of a petroleum well completion; means defining a circumferentially extending, annular seat in the throughbore of the housing, facing downwardly; a flapper; axle means on said flapper laterally offset from a diameter of the flapper; means mounting the axle means with respect to the housing so the flapper is movable between an open condition wherein the flapper is disposed generally parallel to the petroleum flow path, below the annular seat and a closed condition wherein the flapper is seated against the annular seat, interrupting the petroleum flow path; spring means mounted in the housing, said spring means disposed to urge the flapper toward the seat; a tubular piston vertically slidably disposed in the throughbore of the housing so as to be disposed above the valve seat when the flapper is in a closed condition; means defining an upwardly facing surface on said piston; two circumferentially extending seal means disposed between and sealing with the housing and the piston, one above and one below said upwardly facing surface; fluid conduit means communicating through the housing to the ambit of the upwardly facing surface so that pressurized fluid may be admitted to bear against said upwardly facing surface to drive said piston downwardly; stop means in said housing and stop shoulder means on said piston abuttable with one another to limit downward travel of the piston; said piston including downwardly projecting stinger means engageable with the flapper as the piston iS driven downwardly for forcing the flapper to an open condition; and downwardly facing surface means on the piston subject to pressure in the petroleum flow path for causing upward movement of the piston, withdrawing the stinger from forceable opening of the flapper so that the spring may close the flapper; said stinger being tubular and including means defining a lateral port for venting pressure from the region of the throughbore lying exteriorly of the piston between the stop shoulder means on the piston and on the housing.

Claim 14

A safety valve for incorporation in the flow path of petroleum issuing from a petroleum well through a tubing string comprising: a tubular housing forming a part of a petroleum well completion; means defining a circumferentially extending, annular seat in the throughbore of the housing, facing downwardly; a flapper; axle means on said flapper laterally offset from a diameter of the flapper; means mounting the axle means with respect to the housing so the flapper is movable between an open condition wherein the flapper is disposed generally parallel to the petroleum flow path, below the annular seat and a closed condition wherein the flapper is seated against the annular seat, interrupting the petroleum flow path; spring means mounted in the housing, said spring means disposed to urge the flapper toward the seat; a tubular piston vertically slidably disposed in the throughbore of the housing so as to be disposed above the valve seat when the flapper is in a closed condition; means defining an upwardly facing surface on said piston; two circumferentially extending seal means disposed between and sealing with the housing and the piston, one above and one below said upwardly facing surface; fluid conduit means communicating through the housing to the ambit of the upwardly facing surface so that pressurized fluid may be admitted to bear against said upwardly facing surface to drive said piston downwardly; stop means in said housing and stop shoulder means on said piston abuttable with one another to limit downward travel of the piston; said piston including downwardly projecting stinger means engageable with the flapper as the piston iS driven downwardly for forcing the flapper to an open condition; and downwardly facing surface means on the piston subject to pressure in the petroleum flow path for causing upward movement of the piston, withdrawing the stinger from forceable opening of the flapper so that the spring may close the flapper; said stinger being tubular and including means defining a lateral port for venting pressure from the region of the throughbore lying exteriorly of the piston between the stop shoulder means on the piston and on the housing.

Claim 15

The safety valve of claim 11 further including eccentric recess means in said throughbore below said valve seat, adjacent said axle means, for receiving the flapper when the flapper is in an open condition.

Claim 16

The safety valve of claim 11 wherein the valve seat is formed on the lower side of an annular member further provided with arcuate ribs along the outer periphery of the lower side thereof, which ribs extend toward one another sufficiently to receive the opposite ends of said axle means to provide said means for mounting said axle means.