Fiber Optics Leak Detection Systems Performance Evaluation for Detection of Pinhole Leaks in Above-Ground and Buried Pipelines Under Multiphase Flow

Abstract

Providing quick response time and accurate detection of small leaks in multiphase pipelines is of great importance for risk mitigation in the oil and gas industry. The emphasis of implementing state-of-the-art technologies to mitigate both safety and environmental risks in the field becomes of particular importance as aging pipelines transport sour hydrocarbon products crossing populated areas. Fiber Optics Leak Detection Systems (FOLDS) have the capability to detect small pinhole leaks even in multiphase flow, due to its distributed sensing and advanced signal processing features. With this motivation in mind, it is important to evaluate the ability of FOLDS to detect leaks under different scenarios of varying fiber cable location, product phase distribution, propagation media, pressure, temperature, leak sizes and leak locations. Due to the high amount of varying parameters, safety hazards and environmental constraints associated with field testing FOLDS, an industrial third-party multiphase flow facility enables FOLDS performance evaluation across the range of applications of interest. In this particular case, different Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) FOLDS were simultaneously tested for detecting the pipeline leaks. The overall performance test scope and procedure presented in this paper was custom developed to simulate as close as field parameters for validation across multiphase and wet gas flow conditions. The customized performance evaluation test program led to results that show the sensitivity of technology performance to different operational conditions, ranging from physical flow parameters to fiber optic location with respect and leak propagation media. FOLDS solutions performance validation is presented in terms of leak detection, stability and consistency. This leads to a conclusive benchmarking of each solution performance based on the test results for multiphase pipelines. This paper guides the audience through the methodology of customized performance evaluation testing of pinhole leak detection for oil multiphase and wet gas pipelines. It also provides value by highlighting the impact of testing procedures, different flow parameters and installation setups on the actual system performance.