Patent ID: 7713917

Claim:
A thermal insulating composition useful for controlling heat transfer from a production tubing or transfer pipe in a wellbore to one or more surrounding annuli and/or the environment, the composition comprising an organic solvent of low thermal conductivity and a gelling agent hydratable in the solvent, wherein the gelling agent is selected from the group consisting of (i) hydrophobically-modified polyacrylic and acrylic/acrylate copolymers; (ii) terpolymers of acrylamide or (meth)acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and N-vinylformamide; and (iii) terpolymers of acrylamidopropyl trimonium chloride, acrylamide or (meth)acrylamide and at least one comonomer selected from the group consisting of N-vinylformamide, N-vinylacetamide, N-vinylcaprolactam, N-vinylimidazole, N-vinylpyridine, N-vinylpyrrolidone and acrylamidopropyltrimonium chloride; and further wherein the fluid viscosity of the composition is capable of reducing the convection flow velocity within the surrounding annulus of the well or the production tube and/or transfer pipe.