Diyab Gas Export Pilot Project Early Leakage Detection
Authors: Marc Baque 
Published: October 2022

One of prerequisite of any detection system is to get the requirement the risk analysis that estimates mainly the safety and environmental impacts of a loss of containment. From this prerequisite it is possible to consider a strategy for an early detection of a loss of containment, and to choose a method or a technology. Methods of detection belong to two main families: External based Leak Detection System which used local leak sensors to generate a leak alarm. The main External based Leak Detection Systems are acoustic emission detectors, pressure detectors, fiber optic cable, vapor and / or liquid sensing cables;Internal based Leak Detection Systems which used normal field sensors (e.g. pressure transmitters, flowmeters) for leak detection and leak localization. The main internal Leak Detection Systems are:○balancing systems (line balance, volume balance, compensated mass balance etc.);○Real Time Transient Model;○pressure/ flow monitoring;○statistical analysis…

The main External based Leak Detection Systems was studied internally through different evaluation and development programs and for some of them in operation.

The main findings were the followings: The acoustic based detection is sensitive to external noises as well as some pipeline fluid (multi-phase, critical flow, transit phase) and pipeline elements (e.g. elbows, valves). This technology requires the management of high quantity of data, a significant tuning period, and many sensors connected to the pipeline. Distributed Acoustic Sensing (DAS) using the fiber optic cable media is currently used internally to detect real time intrusion.The pressure emission detectors may be insensitive and require accurate pressure measurement. This technology is difficultly practical on short lines, gas or multi-phase pipelines with transient phases.The vapor / liquid sensing cable technology needs to be physically close to the pipe to become wet in case of leakage. These sensitive cables should be replaced or cleaned after a leak. This technology is ne suitable easily for long distance application. Their retrievable capability with the implementation of pulling chamber every few hundred meters needs to be carefully considered. In addition, this technology is highly sensitive. This implies that false alarms may occurred in case of former contamination (presence of hydrocarbon). This technology is also sensitive to the soil disruption, fluid properties and is affected by the ageing (sensitive polymer alteration). However, this technology is suitable for short distance and for some leaks detection when there is no temperature variation between the fluid and the soil.The Fiber optic solution was highly considered for a leak detection through several evaluation programs and, in particular two PIT (Projet d’Innovation Technologique) Projects. These two PIT projects were performed between 2015 and 2019 and presented to the following ADIPEC sessions○(Baque, 2017) 2017 Abu Dhabi International Petroleum Exhibition & Conference SPE-188669-MS Early Gas Detection○(Baque, 2020) 2020 Abu Dhabi International Petroleum Exhibition & Conference SPE-203293-MS Fiber Optic Liquid Leakage Detection

Note: Some of the paragraph parts of this manuscript are extracted from these two SPE documents referred (Baque, 2017) and (Baque, 2020). Other evaluation and development programs not presented previously are also presented in this manuscript.