Abstract: A downhole apparatus includes a casing string with a fluid barrier connected therein defining a lower end of a buoyancy chamber. A rupture disk is spaced from the fluid barrier and defines an upper end of the buoyancy chamber. A degradable plug is connected in the casing string above the rupture disk. The degradable plug defines a flow path to permit flow therethrough to the rupture disk, and is movable from a first to a second position in the casing string.

Abstract: A buoyancy assist tool and a fluid barrier in a casing string define a buoyancy chamber therebetween. The buoyancy assist tool has a housing connected in the casing string with a retaining sleeve detachably connected in the housing. The retaining sleeve is movable from a first to a second position in the housing. A flapper disk is positioned in the housing and covers an upper end of the retaining sleeve in the first position of the retaining sleeve. In the second position of the retaining sleeve the flapper disk is in a retracted position out of the flow path through the housing.

Abstract: A downhole apparatus includes an outer case connectable at upper and lower ends thereof in a casing string. A degradable plug is fixed in an interior of the outer case. A rupture disc is mounted in a port in the wall of the outer case. The port is positioned to communicate a degrading fluid to an axial flow passage defined in a wall of the outer case and the axial flow passage is configured to communicate the degrading fluid back into the interior of the outer case and into the degradable plug.

Abstract: A plug assembly for use in oil and gas wells includes a sleeve having a debris barrier. The plug assembly may have a top sub, a bottom sub, and a middle sub arranged between the top sub and the bottom sub. The middle sub has an interior bore, a valve and a fluid flow channel such that the valve, when opened, allows fluid to flow from an interior bore of the middle sub into the fluid flow channel. The sleeve having the debris barrier is disposed on the middle sub. Fluid flowing in the fluid flow channel moves the sleeve, which moves the debris barrier so that the debris barrier is withdrawn from the fluid flow path through the interior bores of the top sub and the middle sub.

Abstract: A valve housing has a first flapper moveable from an open position in the housing in which two-way flow is allowed to a closed position in which only one-way flow is permitted. A first collet sleeve is moveable from a first position to a second position in the valve housing. The first collet sleeve in the first position retains the flapper valve in the open position. The collet sleeve is moveable from a first position to a second position which allows the flapper to move to a closed position.

Abstract: A downhole apparatus comprises a casing string with a frangible disk positioned therein. A flow barrier is connected in the casing string and spaced downwardly from the frangible disk. The frangible disk and the flow barrier define a buoyancy chamber. The sliding sleeve will impact and shatter the frangible disk into a plurality of pieces that will pass downwardly in the casing after the casing has been lowered to a desired depth.

Abstract: A valve housing has a first flapper moveable from an open position in the housing in which two-way flow is allowed to a closed position in which only one-way flow is permitted. A first collet sleeve is moveable from a first position to a second position in the valve housing. The first collet sleeve in the first position retains the flapper valve in the open position. The collet sleeve is moveable from a first position to a second position which allows the flapper to move to a closed position.

Abstract: A buoyancy assist tool has an outer case and a sleeve disposed in the outer case. The sleeve is movable from first to second positions in the outer case. A permeable membrane is attached to the movable sleeve at a lower end thereof. A rupture disk is mounted in the outer case. Fluid flow through the permeable membrane detaches the sleeve from the outer case and moves the sleeve from the first to the second position. In the second position, the sleeve creates an open bore for the passage of downhole tools therethrough.

Abstract: A buoyancy assist tool has an outer case and a rupture disk connected in the outer case. A sleeve is disposed in the outer case and movable from first to second position in the outer case. A rupture disk membrane of a rupture disk prevents the sleeve from moving to the second position prior to the rupture disk membrane rupturing. The outer case is configured to be connected in a well casing. A lock ring holds the sleeve in the first position.

Abstract: A downhole tool includes a casing string with a fluid barrier connected therein defining a lower end of a buoyancy chamber. A plug assembly connected in the casing string defines an upper end of the buoyancy chamber. The plug assembly has an outer case with a rupture disc positioned therein configured to block flow and to burst at a predetermined pressure. The rupture disk is removable from a flow path through the outer case upon the flow of fluid therethrough.

Abstract: A valve assembly has a housing defining a flow passage therethrough. A first flapper is disposed in the housing. A first sleeve retains the flapper in an open position. At least one lock ring holds the first sleeve in a first position. A tripping ball engages a plurality of disconnected bodies in the sleeve and a force is applied to move the first sleeve from the first to a second position.

Abstract: A packer assembly and valve assembly without special or custom threads are used to provide a threadless float assembly. A packer assembly with inserts disposed in slip wedges is set by applying compressive forces using a setting tool. A valve assembly may be positioned during setting of the packer assembly between a holder and a setting tool insert end or may be positioned abutting a spacer after setting of the packer assembly. A setting tool and a plunger along with a pump are used to apply compressive forces on the packer assembly to set the packer assembly without requiring that the packer assembly or the valve assembly have special threading as the inserts, holder and spacer maintain the components in a stationary position.

Abstract: A downhole apparatus comprises a casing string with a removable plug therein to block flow therethrough. A flow barrier is positioned in the casing below the removable plug and the removable plug and the flow barrier define a buoyancy chamber therebetween. A debris barrier positioned above the removable plug has a plurality of fragments interspersed in a stretchable material and includes a frangible disc.

Abstract: A plug assembly for use in oil and gas wells includes a sleeve having a debris barrier. The plug assembly may have a top sub, a bottom sub, and a middle sub arranged between the top sub and the bottom sub. The middle sub has an interior bore, a valve and a fluid flow channel such that the valve, when opened, allows fluid to flow from an interior bore of the middle sub into the fluid flow channel. The sleeve having the debris barrier is disposed on the middle sub. Fluid flowing in the fluid flow channel moves the sleeve, which moves the debris barrier so that the debris barrier is withdrawn from the fluid flow path through the interior bores of the top sub and the middle sub.

Abstract: A buoyancy assist tool has an outer case and a sleeve disposed in the outer case. The sleeve is movable from first to second positions in the outer case. A permeable membrane is attached to the movable sleeve at a lower end thereof. A rupture disk is mounted in the outer case. Fluid flow through the permeable membrane detaches the sleeve from the outer case and moves the sleeve from the first to the second position. In the second position, the sleeve creates an open bore for the passage of downhole tools therethrough.

Abstract: A downhole apparatus comprises a casing string with a frangible disk positioned therein. A flow barrier is connected in the casing string and spaced downwardly from the frangible disk. The frangible disk and the flow barrier define a buoyancy chamber. The sliding sleeve will impact and shatter the frangible disk into a plurality of pieces that will pass downwardly in the casing after the casing has been lowered to a desired depth.

Abstract: A buoyancy assist tool has an outer case and a rupture disk connected in the outer case. A sleeve is disposed in the outer case and movable from first to second position in the outer case. A rupture disk membrane of a rupture disk prevents the sleeve from moving to the second position prior to the rupture disk membrane rupturing. The outer case is configured to be connected in a well casing.

Abstract: A downhole apparatus comprises a casing string with a removable plug therein to block flow therethrough. A flow barrier is positioned in the casing below the removable plug and the removable plug and the flow barrier defining a buoyancy chamber therebetween. A debris barrier positioned above the removable plug comprises a rigid annular ring with a flexible diaphragm covering the center opening defined by the annular ring.

Abstract: A downhole apparatus comprises a casing string with a fluid barrier connected in the casing string. A degradable plug is positioned in the casing string above the fluid barrier. The degradable plug and fluid barrier define upper and lower ends of a buoyancy chamber in the casing string. The degradable plug may be degraded to leave an open bore through the casing string after the casing string is lowered into a wellbore.

Abstract: A downhole apparatus comprises a casing string with a removable plug therein to block flow therethrough. A flow barrier is positioned in the casing below the removable plug and the removable plug and the flow barrier defining a buoyancy chamber therebetween. A debris barrier positioned above the removable plug comprises a rigid annular ring with a flexible diaphragm covering the center opening defined by the annular ring.