Dual-frequency tags to detect cement curing in wellbore applications
US10450850B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 2015 |
| Grant date | Oct 22, 2019 |
| Priority date | — |
| Expiry date | Jul 1, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/0251
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Micro-Electro-Mechanical System (“MEMS”) tags having high and low resonant frequencies are used to detect the cured or uncured state of wellbore cement. The MEMS tags may be added to wellbore cement, and pumped downhole. An interrogation tool emits a signal at one or both of the resonant frequencies which, in turn, interacts with the MEMS tags to produce a response signal. Since uncured cement has a high attenuation, only the lower resonant frequency response signal is sensed by an interrogation device, thus indicating the cement remains uncured. When the cement cures, its conductivity drops and the attenuation of the higher resonant frequency response signal drops also, thus allowing that signal to be detected by the interrogation device and indicating the cement has cured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.