Distributed fiber sensing in a packer for permanent casing and formation deformation monitoring

A system, comprising:

• a wellbore deformation instrument, comprising:
• an expandable annular cylindrical packer,
• a plurality of assemblies mounted on an exterior circumferential surface of the packer and configured to be pressed against a wellbore surface by the packer, wherein the each of the assemblies comprises:
• at least one fiber-optic coil embedded in a sheet of deformable substrate,
• a tray-shaped receptacle formed from a low thermal conductivity material and attached along a rim of the receptacle to an edge of the sheet with a pressure tight-seal, wherein a pressure-tight compartment formed by the receptacle, the sheet, and the seal contains a high-pressure inert gas, and
• an optical coupler, configured to couple the at least one fiber-optic coil to a fiber-optic cable;
• a fiber-optic cable deployed in a wellbore running from a wellhead into a subsurface formation and optically coupled, through the optical coupler, to each of the at least one fiber-optic coil;
• and
• an optical analyzer, configured to launch a laser pulse into the fiber-optic cable at the wellhead and receive a backscattered laser pulse from each of the at least one fiber-optic coil through the fiber-optic cable.