US 12,281,567 B1
Method for depth identification of leaks in a casing string
Rickey Sullivan, Bakersfield, CA (US)
Assigned to Aera Energy LLC, Bakersfield, CA (US)
Filed by Aera Energy LLC, Bakersfield, CA (US)
Filed on Oct. 4, 2024, as Appl. No. 18/906,660.
Claims priority of provisional application 63/598,846, filed on Nov. 14, 2023.
Int. Cl. E21B 47/117 (2012.01); E21B 47/04 (2012.01); E21B 47/07 (2012.01); G01K 11/3206 (2021.01); G01M 3/00 (2006.01)
CPC E21B 47/117 (2020.05) [E21B 47/04 (2013.01); E21B 47/07 (2020.05); G01K 11/3206 (2013.01); G01M 3/002 (2013.01)] 29 Claims
OG exemplary drawing
 
1. A method for identifying one or more leaks in a casing, the method comprising steps of:
running a temperature measurement device into the casing of a well to obtain temperature-depth data between two depths of the casing in real time;
obtaining at least one set of temperature-depth data;
thermally conditioning the well;
thereafter, using a set of temperature-depth data of the thermally conditioned well to:
a) calculate a series of temperature gradients between the two depths, with a moving average temperature gradient calculated over a window having a value between two and ten feet, recalculated at pre-determined intervals between a minimum interval that temperature measurements can be obtained by the temperature measurement device and ten feet;
b) calculate a mean of moving average temperature gradients;
c) calculate a standard deviation of the moving average temperature gradients;
d) calculate a lower control limit (LCL) using a formula: LCL=X−(M×S) where X is the mean, M is a multiplier having a value between 2.6-3.1 and S is the standard deviation; and
identify the one or more leaks by determining a depth associated with any moving average temperature gradient having a value lower than the lower control limit.