Abstract: Method, devices and systems are provided for measuring deformation in subterranean formations. Such methods include introduction of spaced-apart depth magnetic markers along the longitudinal length of a well bore and measuring the position of each depth marker over time so as to determine deformation of the subterranean formation. In certain embodiments, depth markers comprise rare earth magnets. In further embodiments, orientation of each magnetic bullet is determined over time to determine the change in orientation of each magnetic bullet. Advantages of the methods and devices herein include, but are not limited to, improved accuracy and reliability of deformation measurements and reduced environmental impact due to the avoidance of radioactive markers used by the present invention.

Abstract: Method, devices and systems are provided for measuring deformation in subterranean formations. Such methods include introduction of spaced-apart depth magnetic markers along the longitudinal length of a well bore and measuring the position of each depth marker over time so as to determine deformation of the subterranean formation. In certain embodiments, depth markers comprise rare earth magnets. In further embodiments, orientation of each magnetic bullet is determined over time to determine the change in orientation of each magnetic bullet. Advantages of the methods and devices herein include, but are not limited to, improved accuracy and reliability of deformation measurements and reduced environmental impact due to the avoidance of radioactive markers used by the present invention.

Abstract: An improvement in a tool of the type which is adapted for connection into a drilling string, which tool is adapted to perform a function in the drilling string as a first function. The improvement is a magnetic field source incorporated with the tool so that the tool is adapted to perform a magnetic field source carrying function as a second function. The first function is unrelated directly to the second function.