Casing Flotation Subs

Running casing strings to total depth can be challenging in long laterals, due to drag and high frictional forces that impede the process of pushing casing to bottom. Kobold flotation subs solves this problem by creating an air pocket that increases buoyancy of the casing below the tool, reducing drag forces along the horizontal leg of the well. The buoyancy chamber prevents fluid from filling the casing while running in the well. This “traps” fluid in a column of air in the casing string, allows it to become lighter than the surrounding wellbore fluid. The lightweight casing string can now 'float into the well'.

The flotation sub contains a tempered glass disc that acts as a barrier, holding fluid above the tool until desired casing depth is reached. Surface pressure is then applied, causing the glass disc to shatter into fine debris and enabling circulation. No debris catcher is required because the fine glass particles can be easily circulated out of the casing. Operators can land the productive casing deeper in the wellbore exposing more of the productive wellbore to the completion. The robust glass discs are engineered to withstand high levels of differential pressure and temperature. Once opened, the operator has full wellbore ID.