The pipeline accidents due to faults (leakage and blockage) have been leading to major environmental issues.Various techniques have been established to detect faults in a pipeline.But each having pros and cons.Thus, there is a necessity for early and accurate fault detection to prevent failures.To identify the leaks in the pipelines, there is a necessity to monitor variables.A two-phase transient model is used for two different operating conditions (with leakage and without a leak) for the variable analysis.An OLGA (OiL GaS) based model is used to simulate a leakage and generate data for monitoring variables such as pressure, velocity, rate of flow, and, temperature at inlet and outlet over the flow of pipeline.The leak locations and sizes were varied, and respective variables were studied.The leak sizes were assorted for 0 (no leak), 20 and 50 leak opening, and the inlet and outlet variables were analyzed.Except for the temperature, all other variables are increasing with the movement of the leak location.The mass flow rate has been decreased 0.91 times the original mass flow rate for 20 leak opening condition.The percentage change of variable is relatively constant from the point of the leak.And, a dip of 0.77 times was observed for a 50 leak opening condition which is maintained constant as mentioned above. © 2023, Institute of Technology PETRONAS Sdn Bhd.