US Patent 11879328 Semi-permanent downhole sensor tool

A method and a system for collecting data at a fixed point in a wellbore are provided. An exemplary method includes dropping an untethered measurement tool (UMT) in the wellbore, switching a first magnet to drop a ballast from the UMT at a ballast drop condition, switching a second magnet to attach the UMT to a wall of the wellbore at a wall attachment condition. Data is collected in the UMT while the UMT is attached to the wall of the wellbore. The second magnet is switched to release the UMT from the wall of the wellbore at a wall release condition. The UMT is collected from the wellbore and the data is downloaded from the UMT.