Abstract: An embodiment of a downhole tool for use with a workstring in a wellbore includes a first section, a second section, and a coupling mechanism adapted such that in a first configuration the coupling mechanism couples the first section to the second section. In a second configuration, the coupling mechanism does not couple the first section to the second section. Also disclosed is a method for creating a plug in a wellbore, the method comprising: injecting a slurry into the workstring to form a plug in the wellbore, positioning a flow preventing mechanism into the workstring to prevent fluid flow from exiting the workstring, inducing a coupling mechanism to uncouple a portion of the workstring such that the portion remains with the slurry to create the plug in the wellbore, and removing the first section from the wellbore.

Abstract: An apparatus and method for cementing a casing string in a wellbore. A self-filling tubular cementing collar connected to the lower end of a casing string is provided with one-way flow valving that allows well fluid to enter and self-fill the casing string as it is lowered into the wellbore and automatically prohibits reverse fluid flow from the collar when washing or cementing during forward circulation through the collar. The one-way valving is carried by an axially movable support that can be shifted by a cementing plug moved by pump pressure to permanently seal the entry flow passage after the casing sting is properly positioned in the wellbore.

Abstract: An embodiment of a downhole tool for use with a workstring in a wellbore includes a first section, a second section, and a coupling mechanism adapted such that in a first configuration the coupling mechanism couples the first section to the second section. In a second configuration, the coupling mechanism does not couple the first section to the second section. Also disclosed is a method for creating a plug in a wellbore, the method comprising: injecting a slurry into the workstring to form a plug in the wellbore, positioning a flow preventing mechanism into the workstring to prevent fluid flow from exiting the workstring, inducing a coupling mechanism to uncouple a portion of the workstring such that the portion remains with the slurry to create the plug in the wellbore, and removing the first section from the wellbore.

Abstract: A differential float and cementing valve assembly used to position and cement casing in a wellbore. A leaf spring and other components of the assembly are preferably constructed of composite materials and/or plastics that can be drilled up with polycrystalline diamond compact (PDC) bits. The valve components may be contained within a metallic housing.

Abstract: An embodiment of a downhole tool for use with a workstring in a wellbore includes a first section, a second section, and a coupling mechanism adapted such that in a first configuration the coupling mechanism couples the first section to the second section. In a second configuration, the coupling mechanism does not couple the first section to the second section. Also disclosed is a method for creating a plug in a wellbore, the method comprising: injecting a slurry into the workstring to form a plug in the wellbore, positioning a flow preventing mechanism into the workstring to prevent fluid flow from exiting the workstring, inducing a coupling mechanism to uncouple a portion of the workstring such that the portion remains with the slurry to create the plug in the wellbore, and removing the first section from the wellbore.

Abstract: A small diameter stage cementer assembly 10 and a hydraulically operated packer collar stage cementer 110, including a cementer housing 12 for interconnection with a casing string 14 positionable in a slim-hole wellbore for a cementing operation. The cementer housing 12 including a seat 11 for receiving a lower, drillable portion 335 of an opening sleeve assembly 135 after the upper drillable portion 235 of the opening sleeve assembly 135 has been drilled out. The lower, drillable portion 335 wedges into engagement with the seat 11 to prevent rotation of the drillable portion 335 during drill-out, such that the lower portion 335 may be drilled up using a small diameter bit and drill string, and accommodating a reduced weight on bit. The packer collar embodiment includes a hydraulically actuatable packer 70.

Abstract: An apparatus and method for cementing a casing string in a wellbore. A self-filling tubular cementing collar connected to the lower end of a casing string is provided with one-way flow valving that allows well fluid to enter and self-fill the casing string as it is lowered into the wellbore and automatically prohibits reverse fluid flow from the collar when washing or cementing during forward circulation through the collar. The one-way valving is carried by an axially movable support that can be shifted by a cementing plug moved by pump pressure to permanently seal the entry flow passage after the casing sting is properly positioned in the wellbore.

Abstract: A tubular tool body carried at the end of a drilling rig top drive is received within a drill string being used as a landing string to position casing in a wellbore. External threads on the tool body can be mated with the box threads of the drill string to secure the top drive and drill string together for simultaneous drill string movement and fluid circulation. An annular seal carried about the tool body engages and seals with the internal wall of the drill pipe to prevent drilling fluid leakage when the tool body is received within the drill pipe without thread engagement. The tool has an internal check valve that opens to allow back flow of drilling fluid that may be displaced from the drill pipe as the pipe is lowered into the well. The check valve prevents standing fluid in the top drive from spilling onto the rig floor when the tool is withdrawn from the drill string.

Abstract: A differential float and cementing valve assembly used to position and cement casing in a well bore. A leaf spring and other components of the assembly are preferably constructed of composite materials and/or plastics that can be drilled up with polycrystalline diamond compact (PDC) bits.

Abstract: An improved float valve according to the present invention includes a packer 10 for positioning within a joint of the casing C while at the surface of the well, the packer including a float valve receptacle therein for at least partially receiving a float valve. The float valve body includes a valve seat 56 and a valve member 54 is positioned for selective engagement and disengagement with the valve seat. A guide nose 58 may be optionally provided for positioning within the casing joint between the valve body and the pin end of the casing joint. The float valve body may be reliably fixed and sealed to the packer body. After the packer setting operation, the casing joint and the packer and the float valve may then be positioned as an assembly within the well.

Abstract: A small diameter stage cementer assembly 10 and a hydraulically operated packer collar stage cementer 110, including a cementer housing 12 for interconnection with a casing string 14 positionable in a slim-hole wellbore for a cementing operation. The cementer housing 12 including a seat 11 for receiving a lower, drillable portion 335 of an opening sleeve assembly 135 after the upper drillable portion 235 of the opening sleeve assembly 135 has been drilled out. The lower, drillable portion 335 wedges into engagement with the seat 11 to prevent rotation of the drillable portion 335 during drill-out, such that the lower portion 335 may be drilled up using a small diameter bit and drill string, and accommodating a reduced weight on bit. The packer collar embodiment includes a hydraulically actuatable packer 70.

Abstract: A tubular tool body carried at the end of a drilling rig top drive is received within a drill string being used as a landing string to position casing in a wellbore. External threads on the tool body can be mated with the box threads of the drill string to secure the top drive and drill string together for simultaneous drill string movement and fluid circulation. An annular seal carried about the tool body engages and seals with the internal wall of the drill pipe to prevent drilling fluid leakage when the tool body is received within the drill pipe without thread engagement. The tool has an internal check valve that opens to allow back flow of drilling fluid that may be displaced from the drill pipe as the pipe is lowered into the well. The check valve prevents standing fluid in the top drive from spilling onto the rig floor when the tool is withdrawn from the drill string.

Abstract: A differential float and cementing valve assembly used to position and cement casing in a well bore. A poppet valve mounted in the flapper gate of a check valve provides a regulated back-flow of drilling fluid through the check valve. A leaf spring biases the poppet valve to its closed position. Drilling fluid pressure in the well bore overcomes the spring force to open the poppet valve and permit drilling fluid to back-flow into the casing. The regulated admission of drilling fluid into the casing permits the casing to sink into the well at a controlled rate while automatically maintaining a desired level of drilling fluid in the casing. With the casing at the bottom of the well, a cement slurry is pumped through the casing. A setting ball moving in advance of the cement slurry deactivates the poppet valve and its flapper gate and activates a second check valve in the assembly to prevent cement back-flow.

Abstract: A differential float and cementing valve assembly used to position and cement casing in a wellbore. A poppet valve mounted in the flapper gate of a check valve provides a regulated back-flow of drilling fluid through the check valve. A leaf spring biases the poppet valve to its closed position. Drilling fluid pressure in the wellbore overcomes the spring force to open the poppet valve and permit drilling fluid to back-flow into the casing. The regulated admission of drilling fluid into the casing permits the casing to sink into the well at a controlled rate while automatically maintaining a desired level of drilling fluid in the casing. With the casing at the bottom of the well, a cement slurry is pumped through the casing. A setting ball moving in advance of the cement slurry deactivates the poppet valve and its flapper gate and activates a second check valve in the assembly to prevent cement back-flow.

Abstract: An liner hanger setting mechanism is provided. The setting mechanism of the present invention is basically comprised of a tubular pump down plug receptacle having a plug seat defined therein. A cylindrical pump down setting plug having a central flow passage and a rupturable member disposed therein to prevent flow therethrough is dropped into a work string and the tubular plug receptacle. The pump down setting plug will engage the plug seat and pressure can be increased to the setting pressure required to set a hydraulically actuated liner hanger. The pressure can then be further increased to the rupture pressure of the rupturable member to provide for full bore flow through the pump down setting plug.

Abstract: The present invention relates to reverse-cementing apparatus. The reverse-cementing apparatus is a float apparatus connected in a pipe string to be cemented into a wellbore. The float apparatus includes an outer housing connected to the casing string. A check valve for preventing flow from the wellbore into the pipe string is disposed in the housing. The check valve is releasably disposed in the housing so that it can be removed from the housing once the pipe string is in place. A flow path for fluid from the wellbore into the pipe string is therefore provided. Cement displaced into the annulus will cause fluid in the wellbore to enter the pipe string through the housing so that the pipe string can be cemented in place utilizing a reverse-cementing method.

Abstract: An apparatus for opening perforations in a casing string. The casing string has a special casing section defining a plurality of holes therethrough. Rupturable ceramic discs or inserts are disposed in said holes and retained therein. The ceramic discs or inserts are adapted to withstand the fluid differential pressures normally present in the wellbore but are rupturable in response to impact by a mild explosive charge. The explosive charge is provided by detonating a length of det-cord disposed in the casing string adjacent to the holes in the special casing section. A method of perforating using this apparatus is also disclosed.

Abstract: The present invention provides an improved subsurface release cementing plug apparatus for use in a string of pipe during the cementing of the pipe in a well bore. The apparatus includes a hollow cementing plug seat member adapted to be connected in the string of pipe near the bottom thereof and a cementing plug assembly releasably connectable to a circulation tool or casing running tool in the top of the string of pipe. The cementing plug assembly includes a top cementing plug having an external annular seating surface formed thereon for sealingly engaging a top internal annular seating surface of the cementing plug seat member, and a bottom cementing plug releasably connected to the top cementing plug having an external annular seating surface formed thereon for engaging a bottom internal annular seating surface of the cementing plug seat member.

Abstract: The present invention provides an improved cementing inflation packer tool and methods of using the tool. The tool includes of a tubular housing having a packer inflating port disposed therein and a packer inflating port opening sleeve slidably disposed within the housing. The opening sleeve is movable between a closed position and an open position by a first cementing plug. An external packer sleeve having a pressurized fluid inflatable packer element attached thereto and a cementing port therein is sealingly disposed over the outer surface of the housing and the packer inflating port. The external packer sleeve provides a passageway from the packer inflating port to the inflatable packer element and check valve means are disposed in the passageway. A fluid rupturable member having a predetermined rupture pressure is sealingly attached over the cementing port.

Abstract: A stage cementer with integral inflation packer. The apparatus comprises a mandrel with an external closing sleeve and an operating sleeve interlocked therewith. Below the operating sleeve is an opening sleeve. The opening sleeve is mechanically actuated by a pump-down plug to actuate the opening sleeve and thereby to allow inflation of a packer portion disposed around said mandrel. An anchor ring is disposed in said mandrel and engaged therewith by a retainer ring. The anchor ring limits movement of the opening sleeve, and a shallow portion of a groove prevents radially inward movement of the retainer ring so that the anchor ring remains lockingly engaged with the mandrel. A back check valve prevents the packer from deflating. When the packer portion is inflated, a packer shoe slidably moves about an outer surface of the closure sleeve. After the packer portion is inflated, additional pressure is applied which ruptures a rupture disc to open a port to the well annulus above the packer portion.