Abstract: A float collar tool for running a casing string assembly into a wellbore includes a non-fragmenting rupture disc that temporarily isolates light fluid trapped in a lower portion of the casing string from heavier fluid in the upper portion of the casing string, thereby reducing the horizontal weight of the casing string by an amount sufficient to overcome a drag force. After the casing string is landed at a final location in the wellbore, the rupture disc is burst by increasing fluid pressure in the upper portion of the casing string. The increased pressure activates a piston that then moves the burst rupture disc into a protective region of the tool so that the inside diameter of the casing string is substantially restored.

Abstract: An apparatus for at least partially sealing an annulus of a wellbore comprises a hollow mandrel pipe adapted to attach to a tubing string, and a cylindrical cage surrounding and attached to an exterior length of the mandrel pipe, the cylindrical cage having a plurality of generally lengthwise tortuous path apertures generally parallel with one another between the two open ends of the mandrel pipe, the plurality of generally lengthwise tortuous path apertures defining a plurality of bow springs therebetween, the plurality of bow springs bowed outward from the mandrel pipe.

Abstract: A float collar tool for running a casing string assembly into a wellbore includes a non-fragmenting rupture disc that temporarily isolates light fluid trapped in a lower portion of the casing string from heavier fluid in the upper portion of the casing string, thereby reducing the horizontal weight of the casing string by an amount sufficient to overcome a drag force. After the casing string is landed at a final location in the wellbore, the rupture disc is burst by increasing fluid pressure in the upper portion of the casing string. The increased pressure activates a piston that then moves the burst rupture disc into a protective region of the tool so that the inside diameter of the casing string is substantially restored.

Abstract: An apparatus for at least partially sealing an annulus of a wellbore comprises a hollow mandrel pipe adapted to attach to a tubing string, and a cylindrical cage surrounding and attached to an exterior length of the mandrel pipe, the cylindrical cage having a plurality of generally lengthwise tortuous path apertures generally parallel with one another between the two open ends of the mandrel pipe, the plurality of generally lengthwise tortuous path apertures defining a plurality of bow springs therebetween, the plurality of bow springs bowed outward from the mandrel pipe.