Patent ID: 9575206
Date: 2017-02-21
CPC Classifications: C04B,C09K,E21B,G01V

Claim:
1. A method for monitoring a subterranean well structure at least partially composed of a first doping material comprising: moving a logging tool in the subterranean well structure; emitting neutrons towards the subterranean well structure at least partially composed of a first doping material; detecting and counting activation gamma rays emitted by the subterranean well structure in response to the neutrons; determining, with a processor, a ratio between the counted number of detected activation gamma rays and an expected number of detected activation gamma rays; and determining information corresponding to a characteristic of the well structure based on the ratio; wherein the logging tool is moved relative to the subterranean well structure at a velocity that depends on: a distance between a neutron source and a gamma ray detector of the logging tool; and a gamma decay half-life corresponding to the first doping material.