Annulus pressure operated closure valve with improved power mandrel

An apparatus for use in a well, comprising:

• a cylindrical housing having an open bore therethrough and a power port through a wall thereof;
• a power mandrel in said open bore having an annular piston for moving said power mandrel in a first direction responsive to fluid pressure exterior of said cylindrical housing communicated to said annular piston through said power port;
• restraining means, located on a side of said annular piston opposite said power port and between said power mandrel and said cylindrical housing, for restraining movement of said power mandrel in said first direction until the pressure exterior of said housing exceeds a predetermined value, and for releasing said power mandrel when said pressure exterior of said housing exceeds said predetermined value;
• and
• interior pressure balance means for balancing an interior pressure of said open bore, and a longitudinal force caused thereby, across said restraining means to prevent loading of said restraining means in a direction parallel to a longitudinal axis of said power mandrel due to said interior pressure.

An apparatus for use in a well, comprising:

• a cylindrical housing having an open bore therethrough and a power port through a wall thereof;
• a power mandrel in said open bore having an annular piston for moving said power mandrel in a first direction responsive to fluid pressure exterior of said cylindrical housing communicated to said annular piston through said power port;
• restraining means between said power mandrel and said cylindrical housing for restraining movement of said power mandrel in said first direction until the pressure exterior of said housing exceeds a predetermined value, and for releasing said power mandrel when said pressure exterior of said housing exceeds said predetermined value;
• and
• shock absorber means for absorbing a longitudinal shock force exerted upon said restraining means due to a varying pressure exterior of said housing, until said pressure exterior of said housing exceeds said predetermined value.

A drain valve apparatus, comprising:

• a cylindrical housing having a drain port disposed in a wall thereof;
• a cylindrical drain valve sleeve disposed about an outer cylindrical surface of said housing;
• and
• actuating collar means, rotatably disposed about said housing and threadedly connected to said drain valve sleeve, for moving said drain valve sleeve longitudinally relative to said housing when said actuating collar is rotated relative to said housing, said drain valve sleeve being movable between a first position wherein said drain port is closed and a second position wherein said drain port is open.

A releasable locking apparatus, comprising:

• an outer cylindrical tubular member;
• an inner cylindrical member received within said outer cylindrical tubular member;
• and
• frangible restraining means located between said inner cylindrical member and said outer cylindrical tubular member and including a carrying structure arranged for force transmitting engagement with a surface of said inner cylindrical member, said frangible restraining means being further characterized as a means for restraining movement of said inner cylindrical member relative to said outer cylindrical tubular member until a force exerted on said carrying structure by said surface of said inner cylindrical member exceeds a predetermined value.

A method of releasably locking an outer cylindrical tubular member to an inner cylindrical member received within said outer cylindrical tubular member, said method comprising the steps of:

• disposing a frangible restraining means between said inner cylindrical member and said outer cylindrical tubular member, said frangible restraining means including inner and outer concentric sleeves and shear pin means connected between said inner and outer concentric sleeves;
• engaging a surface of said inner cylindrical member with said inner concentric sleeve for transmission of force in a first longitudinal direction to said inner concentric sleeve;
• engaging a surface of said outer cylindrical tubular member with said outer concentric sleeve for transmission of force in a second dirction opposite said first direction to said outer concentric sleeve;
• exerting forces in said first and second directions from said inner cylindrical member and said outer cylindrical tubular member to said inner and outer concentric sleeves, respectively;
• moving said inner concentric sleeve longitudinally in said first direction relative to said outer concentric sleeve;
• and thereby
• shearing said shear pin means;
• and
• releasing said inner cylindrical member relative to said outer cylindrical tubular member.