Well casing flotation device and method

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

• a duct, a part of which forms a flotation portion capable of excluding some of said first fluid and containing a second fluid when said duct segment is installed in said cavity, said flotation portion having a first end generally distal from a second end;
• means for sealing said second end;
• means for unsealing said second end;
• means for removing said second fluid from said duct through said unsealed second end;
• wherein said apparatus is shaped and dimensioned to prevent contact of said removed second fluid from said excluded first fluid when said duct segment is installed in said cavity;
• and
• means for circulating a third fluid from said duct to said cavity and back to said duct when said second end is unsealed.

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

• a duct, a part of which forms a flotation portion capable of excluding some of said first fluid and containing a second fluid when said duct segment is installed in said cavity, said flotation portion having a first end generally distal from a second end;
• means for limiting inflow of said first fluid attached to said duct and forming said first end;
• means for sealing said second end comprising:
• a slidable member having a fluid passageway shaped and dimensioned to allow removal of said second fluid from said flotation cavity, said slidable member located within said duct and forming said second end of said flotation portion;
• a plug capable of sealing said passageway;
• and means for releasably attaching said slidable member within said duct;
• means for unsealing said second end;
• means for removing said second fluid from said duct through said unsealed second end;
• and
• wherein said apparatus is shaped and dimensioned to prevent contact of said removed second fluid from said excluded first fluid when said duct segment is installed in said cavity.

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

• a duct, a part of which form a flotation portion capable of excluding some of said first fluid and containing a second fluid when said duct segment is installed in said cavity, aid flotation portion having a first end generally distal from a second end;
• means for sealing said second end comprising a piston-like air trapping device having duct contactable elastomeric sliding seals, a fluid passageway, and a slidable plug blocking said passageway;
• means for unsealing said second end;
• means for removing said second fluid from said duct through said unsealed second end;
• and
• wherein said apparatus is shaped and dimensioned to prevent contact of said removed second fluid from said excluded first fluid when said duct segment is installed in said cavity.

An apparatus for installing a duct within the boundary of an underground hole partially containing a first fluid comprising:

• a duct shaped and dimensioned to be run into said hole;
• a flow restrictor attached to one end of said duct so as to restrict flow of said first fluid into the interior of said duct portion;
• a plug slidably attached within said duct so as to form a floatation cavity between said plug and said restrictor capable of containing a second fluid, said plug having a fluid communication port within said plug extending from said flotation cavity to an adjacent internal portion of said duct;
• means for partially filling said adjacent cavity with a third fluid;
• means for releasably blocking said port;
• means for unblocking said port so as to allow a partial exchange of said fluids from said flotation cavity to said adjacent cavity;
• means for removing said second fluid wherein said withdrawn second fluid does not contact said hole boundary;
• means for sliding said plug towards said flow preventer until said plug contacts said flow restrictor;
• means for attaching said plug to said flow restrictor;
• means for removing said attached plug and flow restrictor from said duct;
• and
• means for circulating a third fluid from said duct to said hole and back to said duct when said port is unblocked.

A process useful in installing a duct segment within a first fluid containing hole using a second fluid, a fluid inflow restriction device, a means for circulating fluid from the duct to the hole and back to the duct, 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 generally capable of excluding said first fluid:
• attaching said fluid trapping insert to the other end of said flotation portion within said duct segment;
• installing said duct segment into said hole;
• removing said second fluid from said duct segment without said second fluid contacting said excluded first fluid;
• and
• circulating a fluid from said duct segment to said hole and back to said duct segment.

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

• a duct, a part of which forms a flotation portion capable of excluding some of said first fluid and containing a second fluid when said duct is installed in said cavity, said flotation portion having a first end generally distal from a second end;
• means for sealing said second end;
• means for unsealing said second end;
• means for removing said second fluid from said duct through said unsealed second end;
• and
• means for circulating at least a portion of a third fluid from said duct to said cavity and back to said duct after removal of said second fluid.