Method and apparatus for placing and interrogating downhole sensors

Abstract

A method and system is shown to passively monitor cement integrity within a wellbore. Different types of sensors (pressure, temperature, resistivity, rock property, formation property etc.) are “pumped” into place by placing them into a suspension in the cement slurry at the time a well casing is being cemented. The sensors are either battery operated, or of a type where external excitation, (EMF, acoustic, RF etc.) may be applied to power and operate the sensor, which will send a signal conveying the desired information. The sensor is then energized and interrogated using a separate piece of wellbore deployed equipment whenever it is desired to monitor cement conditions. This wellbore deployed equipment could be, for example, a wireline tool.

Dependencies are inferred from the claim text.