Well casing flotation device and method

A process useful for installing a duct segment within an underground hole, which hole contains a first fluid and extends underground from at least a near surface location to an underground location vertically and horizontally displaced from said near surface location, wherein a first imaginary straight line connecting said locations intersects a vertical line commencing downward from said near surface location to form the vertex of an angle no greater than 90 degrees, said process comprising:

• inserting said duct segment into said hole at least to said underground location, said duct having a flotation chamber containing a sufficient amount of second fluid having a density less than said first fluid so as to produce a buoyant force on said duct when said duct is immersed in said first fluid in said underground hole, said flotation chamber further comprising:
• a fluid flow restriction device attached to said duct at one end of said flotation chamber;
• a fluid trapping insert attached to the other end of said flotation chamber and
• wherein said angle is at least about 63.4 degrees and said horizontal displacement is substantial.