Sealing wells (US Patent 4,110,225, 1978)

William S. Cagle received US Patent No. 4,110,225 on August 29, 1978, filed March 3, 1975.

The patent's abstract:

Zones of lost circulation and other undesired fluid communication channels into a wellbore are sealed by isolating a volume in the well including such a zone and applying greater than formation pressure to a novel slurry spotted in the zone until it hardens into a solid, drillable seal. Redrilling the bore can be accomplished even in soft, geologically young formations, without damaging the seal. The slurry contains per barrel from 5-50 pounds diatomaceous mix (see below), from about 35 to about 350 pounds of oil well cement, and at a minimum about 5 to 6 pounds of a flake type lost-circulation agent. Preferably, the weight per barrel of lost circulation agents is in the range of about 15 to 30 pounds of a mixture containing flakes, fibers, and hard granules. Diatomaceous mix is powdered diatomaceous earth containing about 2% of ground lime and 8% of ground asbestos fibers.

Where it was listed

• Asbestos, February 1979, in its patents department (the year's issues)