OPTICAL CASING COLLAR LOCATOR SYSTEMS AND METHODS.

摘要

Disclosed are fiber optic enabled casing collar locator systems including a wireline sonde or a coil tubing sonde apparatus configured to be conveyed through a casing string by a fiber optic cable. The sonde includes at least one permanent magnet producing a magnetic field that changes in response to passing a collar in the casing string. Such magnetic field changes induce voltages changes within associated pick-up electrical coil conductors. Some embodiments include a cylinder configured to change its diameter in response to the changes in the magnetic field and/or impressed voltage, and an optical fiber wound around the cylinder to convert the cylinder diameter change into an optical path length change for light being communicated along the fiber optic cable. The cylinder may include a magnetostrictive material or a piezoelectric material.