Interventionless frangible disk isolation tool

A pressure isolation tool comprising:

• a housing having a bore;
• a first frangible disk having an outer surface and an inner surface and a base supporting the disk in the bore against hydrostatic pressure in the bore above the disk, and a dome and a cylindrical section, the cylindrical section having cylindrical outer walls perpendicular to a transverse plane of the bore, wherein the dome of the first frangible disk is transverse to the bore and blocking the bore when in an unbroken condition;
• a rupturable membrane in fluid communication with the bore;
• a piston assembly engaging the housing and the first frangible disk, wherein the piston assembly comprises a slideable piston;
• and
• a multiplicity of fingers located at least partly between the piston and the cylindrical outer walls of the cylindrical section of the first frangible disk;
• wherein the slideable piston is configured to move from a first position to a second position upon rupture of the rupturable membrane;
• wherein movement of the piston to the second position causing the fingers to break the first frangible disk and open the bore.

A pressure isolation tool comprising:

• a housing having a bore;
• a first frangible disk having an outer surface and an inner surface, and a dome and a cylindrical section having outer walls, wherein the dome of the first frangible disk is transverse to the bore when in an unbroken condition;
• a rupturable membrane in fluid communication with the bore;
• a piston assembly engaging the body and the frangible disk, wherein the piston assembly comprises a slideable piston;
• and
• a multiplicity of fingers between the piston and the cylindrical section of the first frangible disk;
• wherein the slideable piston is configured to move from a first position to a second position upon rupture of the rupturable membrane;
• movement of the piston to the second position causing the fingers to pivot against the outer wells of the cylindrical section of the first frangible disk with sufficient inward force to break the first frangible disk and open the bore.

A downhole well isolation tool comprising:

• a housing having an upper end and a lower end, the housing having an exterior wall and having an interior wall, the housing defining a bore having a bore axis;
• an upper frangible disk, the upper frangible disk having an outer wall and an inner wall, a cylindrical section and a generally hemispherical dome, wherein the frangible first disk in an unbroken state substantially blocking the bore, and defining an upper bore above the frangible disk and a lower bore below the frangible disk;
• a finger assembly comprising multiple fingers, each finger having a first position and a second position, at least a portion of some of the multiplicity of fingers adjacent the frangible disk cylindrical section outer wall when in the first position and inward from the first position when in the second, inward position;
• a piston assembly engaging the housing interior wall, the piston assembly comprising a piston having a beveled leading edge, the piston including a piston wall having “O” rings engaged therewith, the piston slideable with respect to the housing interior wall and the fingers of the finger assembly between a first, uphole position and a second, downhole position;
• a rupturable membrane assembly having a rupturable membrane, the rupturable membrane assembly in fluid connection with the upper bore, the rupturable membrane capable of rupturing at a membrane rupture pressure;
• a head space, the head space not in fluid communication with the upper bore before the membrane ruptures but in fluid communication with the upper bore when the membrane ruptures;
• wherein the piston is moveable from the first position toward the second position, responsive to rupture of the rupturable membrane;
• and
• wherein the movement of the piston toward the second position causes the piston to force at least some of the fingers from the first position to the second position and into the cylindrical section of the upper frangible disk with sufficient force to break the frangible disk and unblock the bore.

A pressure isolation tool comprising:

• a housing having a bore;
• a first frangible disk having an outer surface and an inner surface, and a dome and cylindrical section having an outer wall;
• wherein the dome of the first frangible disk is transverse to the bore when in an unbroken condition;
• a rupturable membrane in fluid communication with the bore;
• a piston assembly engaging the body and the frangible disk, wherein the piston assembly comprises a slideable piston;
• and
• a multiplicity of fingers between the piston and the cylindrical section of the first frangible disk;
• wherein the slideable piston and the fingers are configured to move from a first position to a second position upon rupture of the rupturable membrane;
• wherein the piston and fingers are configured and positioned relative to the outer wall of the cylindrical section such that movement of the piston to the second position causes the fingers to first break the first frangible disk by creating multiple cracks in the outer walls of the first frangible disk, which cracks then spread to the dome causing the bore to open.