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Pipeline Technology Journal 2-2015

Latest developments and news from the pipeline industry

RESEARCH / DEVELOPMENT / TECHNOLOGY INTRODUCTION Many countries depend on oil and gas for foreign exchange earnings and as such, oil and gas pipe- lines are critical infrastructures that require safe operations and adequate security. Prior to last two decades, pipeline incidents were predominantly caused by corrosion. However, after the 9/11 inci- dent in USA in 2001, a change in the trend of the causes of pipeline incidents has been observed. Third party interference is now identified as the leading cause of pipeline incidents. Sun & Wen [1] maintained that ninety-five percent of pipeline inci- dents are as a result of artificial damage according to recent statistics. Traditional pipeline monitoring systems have al- ways focused on leak detection systems. Howev- er, due to change in the trend of causes of pipeline incidents, there should be a corresponding change in the priority of monitoring system in order to ad- dress the new challenges. This paper aims at high- lighting the need for external interference detection systems for pipelines and proposing an integrated monitoring system that will be effective in detect- ing external interferences. It categorises pipeline monitoring systems in two groups, external inter- ference detection and leak detection systems. The increasing rate at which pipeline sabotage and theft contribute to pipeline incidents in recent times is highlighted. Also an analysis or comparison of the strengths and weaknesses of the state-of-the art pipeline monitoring techniques is presented. BACKROUND There have been various classification schemes for leak detection sys- tems in the literature. Based on their technical nature, Murvay and Silea [2] presented three classes of leak detection systems including Hard- ware, Software and Non-technical Methods. Though the classification was well done, most hardware based methods depend on software for their analysis while software based methods need hardware to capture data. KROHNE [3] first categorised leak detection systems into continuous and non-continuous systems before going further to sub-divide contin- uous systems into external and internal detection systems. This paper has categorised pipeline monitoring systems in two, external interfer- ence and leak detection systems. Each of these is further divided into continuous and non-continuous systems. Furthermore, the continuous systems under leak detection systems are further categorised in two, external and internal systems. Continuous systems are those that work continuously without stoppage or interruption once they are installed. Non-continuous systems however may not cover the entire pipeline section at the same time or may stop functioning at some point. For instance, a patrol team monitoring a section of pipeline may go for a break, or may have a routine schedule for pipeline inspection. The cate- gorisation is shown in Figure 1. CAUSES OF PIPELINE INCIDENTS Pipeline incidents could result from corrosion, natural disaster, opera- tional errors, external interference as well as construction and material defects. Among these, external interference and corrosion have been the two leading causes of pipeline incidents although only external in- terference is discussed below. PIPELINE SABOTAGE AS EXTERNAL INTERFERENCE Reports according to Okoli and Orinya [5] maintain that a total of 16,083 pipeline incidents out of which 15, 685 cases were due to pipeline sab- otage were recorded in Nigeria between 2002 and 2012 as found in [6]. The remaining 398 cases (2.4 per cent) were due to pipeline ruptures. This research analysed about 813 major pipeline incidents from Shell Petroleum Development Company incident database in Nigeria from 2011 to 2014. As shown in figure 2, 614 incidents (75%) resulted from Sabotage, 192 incidents (24%) from operational error, and the causes of 5 incidents (1%) were yet to be determined while the causes of 2 inci- dents (≈0%) were specified as others. Also, through secondary sources, yearly accounts of pipeline vandalism in Nigeria were collated as shown in figure 3. Pipeline sabotage has been reported as the prevalent cause of pipeline incidents in countries like Nigeria, Indonesia, US, UK, Canada, Iran and Iraq [4]. PIPELINE MONITORING TECHNIQUES EXTERNAL INTERF. DETECTION NON- CONTINOUS UAV Method Helicopters Patrol Teams GIS / GPS Methos CONTINOUS Satellite Method Wireless Sensor Networks Seismic Sensor Method Video Monitoring Acoustics LEAK DETECTION NON- CONTINOUS Helicopters Smart Pigging Inspection Dogs Patrol Teams GIS / GPS Method UAV Method CONTINOUS External Systems Fibre Optics Acoustics Sensor Hoses Video Monitoring Internal Systems Pressure Point Analysis Mass Balance Method Statistical Methos RTTM Based System E-RTTM Figure 1: Classification of Pipeline Monitoring Techniques (Adapted from [3]) PIPELINE TECHNOLOGY JOURNAL 47

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