Abstract: The invention provides a system and computer program for identifying the depth of leaks in well casing strings after receiving temperature-depth data from a thermally conditioned well. Upon receiving the data, the system calculates moving average temperature gradients over a specified length of the casing. It then computes the mean and standard deviation of these gradients to determine a lower control limit (LCL) using a predefined formula. The system identifies leak depths by locating gradients below the LCL. The computer program generates control charts, visual alerts, and detailed reports to facilitate leak detection, offering a streamlined and effective approach to well integrity assessment.

Abstract: A method for detecting leaks in a casing involves running a fiber-optic distributed temperature sensing cable into a well casing to obtain at least one trace in real time. The method includes thermally conditioning the well by inert gas injection and utilizing a trace to calculate moving average temperature gradients at predetermined intervals, determine the mean and standard deviation of these gradients, and establish a lower control limit based on the mean and standard deviation. By identifying any moving average temperature gradient below the lower control limit, the method enables the determination of the depth associated with leaks in the casing.