Well casing flotation device and method

A process useful in installing a duct segment within a first fluid containing cavity within a material, the process using a second fluid having a density less than said first fluid, a first fluid inflow restriction device, means for circulating fluid from the duct segment to the cavity and back to the duct segment, a fluid trapping duct insert having a fluid port, and a fluid conduit capable of providing a fluid passageway between said port and said restriction device within said duct segment, said process comprising:

• attaching said fluid inflow restriction device to said duct segment, said inflow restriction device comprising one end of a flotation portion of the duct;
• attaching said fluid trapping insert to the other end of said flotation portion within said duct segment, whereby said duct segment, restriction device, and insert form a flotation portion capable of containing said second fluid and excluding some or all of said first fluid;
• attaching one portion of said fluid conduit to said fluid port and a second portion of said fluid conduit to said restriction device;
• and
• translating said conduit and flotation portion containing duct segment into a position within said cavity.

An apparatus useful in installing a duct into a cavity within a material, said cavity containing a first fluid, said apparatus comprising:

• a duct, part of which forms an exterior portion of a flotation hollow capable of excluding at least some of said first fluid when containing a second fluid having a density less than said first fluid and when said duct is at least partially located within said cavity, said flotation hollow having a first end generally distal from a second end;
• a conduit, part of which forms an interior portion of said flotation hollow, said conduit providing a fluid passageway between said first end and said second end;
• means for restricting a flow of first fluid from at or near said first end to said flotation hollow and capable of flowing fluid through said conduit;
• and
• means for sealing said second end except for said conduit.

An apparatus useful in installing a duct into a cavity within a subterranean formation, said cavity containing a first fluid, said apparatus comprising:

• a duct, part of which forms an exterior portion of a flotation hollow capable of containing a second fluid having a density less than said first fluid, said flotation hollow having a first end generally distal from a second end;
• means for first end restricting said first fluid from entering said flotation hollow;
• means for second end restricting said first fluid from entering said flotation hollow and containing said second fluid within said flotation hollow;
• and
• an inner conduit for communicating fluid between said first end restricting means and said second end restricting means wherein said inner conduit forms an inner portion of an annular flotation hollow.

A process useful in installing a duct segment within a first fluid containing hole using a second fluid, a fluid inflow restriction device, and a fluid trapping duct insert, said process comprising:

• attaching said fluid inflow restriction device to said duct segment to form one end of a flotation duct portion capable of containing a second fluid and capable of excluding said first fluid;
• attaching said fluid trapping duct insert to the other end of said flotation duct portion within said duct segment;
• attaching a fluid conduit within said flotation duct portion connecting said fluid inflow restriction device to said fluid trapping duct insert;
• installing said duct segment into said hole;
• and
• flowing a cement slurry through said fluid conduit.

A process for moving a duct to a position within a cavity in the earth containing a first fluid comprising:

• inserting said duct into a position within said cavity, said duct having a flotation chamber capable of containing a second fluid having a density less than said first fluid, said flotation chamber comprising:
• a fluid flow restriction device attached to said duct at one end of said flotation chamber;
• a fluid trapping insert attached to said duct at the other end of said flotation chamber;
• and
• a fluid conduit attached to said flow restriction device and said trapping insert comprising a fluid passageway for transferring fluid from said one end of said flotation chamber to said other end.

An apparatus useful in installing a duct into an underground well containing a first fluid, said apparatus comprising:

• a duct capable of containing a flotation portion of said duct a second fluid having a density less than said first fluid;
• first means for restricting fluid flow attached to an upwell position of said duct, said first means comprising one end of said flotation portion;
• second means for restricting fluid flow attached to a downwell position of said duct, said second means comprising the other end of said flotation portion;
• an inner fluid conduit extending from said one end to said other end within said flotation portion;
• and
• means for moving said duct into a set position within said cavity.

An apparatus useful in inserting a duct into an underground well from a first location to a second location wherein said second location is displaced a substantial horizontal distance from said first location, and said well contains a first fluid which is not a cement slurry, said apparatus comprising:

• a duct having an axis, at least part of said duct forming an exterior portion of a flotation chamber capable of containing a second fluid not miscible with said first fluid and having a density less than said first fluid, said flotation chamber having an upwell end when installed in said well;
• means at said upwell end for restricting said first fluid from entering said flotation chamber and for containing said second fluid;
• and
• means for inserting at least a portion of said flotation chamber from said first location to at least said second location absent substantial non-gravity inserting forces along said axis, wherein said horizontal displacement is greater than would have occurred without said flotation chamber.

An apparatus for transporting a hydrocarbon fluid from an underground location to a surface location, said apparatus comprising:

• a wellbore extending from a surface location to an underground location and containing a wellbore fluid which is not a cement slurry, said underground location being vertically and horizontally displaced from said surface location;
• a duct extending within said wellbore from said surface location to said underground location;
• a flotation chamber within said duct which contains a flotation fluid which is not miscible in said wellbore fluid and has a density less than said wellbore fluid;
• and
• wherein said horizontal displacement is at least 6,000 feet and said vertical displacement is less than 5,000 feet.

An apparatus for installing a duct segment within an underground hole containing a first fluid using a compressible second fluid less dense than said first fluid, said apparatus comprising:

• a flotation chamber having a first size within said duct segment for holding said second fluid and capable of substantially excluding said first fluid, said flotation chamber further comprising:
• a fluid inflow restriction device attached to said duct segment to comprise one end of said flotation chamber;
• a slidable fluid trapping insert attached to the other end of said flotation chamber, said insert capable of releasing said second fluid;
• and
• wherein said insert is capable of repositioning within said duct segment to change the size of said flotation chamber prior to releasing most of said second fluid.