CONCENTRIC TUBING HAVING BONDED INSULATION WITH THE ANNULUS

摘要

An insulated concentric tubing well element having an inner tubing and an outer tubing with a substantially solid insulating material in the annulus between the inner and outer tubing. A bonding material fills the voids in the annu?s and the surface of the solid insulating material. The bonding material prevents movement within the annulus and seals the annulus. Calcium silicote is disclosed as a suitable material for the solid insulation and sodium silicate is disclosed as the bonding material. A method is disclosed for producing the complete well element.