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 |
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.
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