US 12,332,401 B2
System and method for downhole gamma ray inspection behind multistring completions
Feyzi Inanc, Houston, TX (US); Joseph Olaiya, Houston, TX (US); Allan Jones, Houston, TX (US); Peng Yuan, Houston, TX (US); and Toyli Anniyev, Houston, TX (US)
Assigned to Baker Hughes Oilfield Operations LLC, Houston, TX (US)
Filed by Baker Hughes Oilfield Operations LLC, Houston, TX (US)
Filed on Nov. 7, 2022, as Appl. No. 17/982,097.
Claims priority of provisional application 63/276,029, filed on Nov. 5, 2021.
Prior Publication US 2023/0144478 A1, May 11, 2023
Int. Cl. G01V 5/12 (2006.01); E21B 47/00 (2012.01); E21B 47/005 (2012.01); E21B 47/10 (2012.01)
CPC G01V 5/12 (2013.01) [E21B 47/005 (2020.05); E21B 47/10 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for identifying a defect within a cement layer of a multistring wellbore, comprising:
deploying a gamma scanner into the multistring wellbore, the gamma scanner including at least one source and at least one detector, the at least one source emitting radiation into the multistring wellbore and the at least one detector receiving backscatter radiation, wherein the emitted radiation is directable about a wellbore axis to obtain an azimuthal scan of the multistring wellbore;
obtaining, from the gamma scanner, a count rate associated with at least one region of interest of the multistring wellbore;
identifying, based at least in part on data acquired from the gamma scanner, a background profile for the multistring wellbore, wherein the background profile includes at least sinusoidal background data;
removing the background profile from the count rate; and
identifying, within the at least one region of interest, a defect within the cement layer.