High-precision pipeline leakage monitoring, alarm, and location system

Leakage is a major fault in the operation of oil pipelines. During the operation of oil pipelines, leakage accidents occur from time to time due to reasons such as corrosion-induced perforations and other external forces, causing significant economic losses to oil fields. Especially in recent years, the security situation in oil-producing areas has been deteriorating steadily; organized oil theft activities have become rampant, severely disrupting normal oil transportation operations and posing significant safety risks to production. Therefore, leak monitoring not only becomes an important part of the safe production management of oil pipelines, but is also an essential guarantee for their proper operation. Implementing leak monitoring for oil pipelines is of great significance for promptly detecting leakage faults, ensuring the safe operation of oil transportation and pipelines, reducing cases of oil theft, and improving the modern management level of long-distance pipelines. 　 Automatic monitoring technology for oil pipeline leaks is widely used abroad; developed countries such as the United States have enacted laws requiring pipelines to be equipped with effective leak detection systems. Research on pipeline leak detection technology in our country started relatively late; institutions such as Tsinghua University and Tianjin University began preliminary studies in the mid-1990s, while actual application only emerged in recent years. Due to the deteriorating security situation in oil-producing areas and the rampant crime of thieves drilling holes to steal oil, technologies that facilitate leak detection have seen rapid large-scale research and adoption. 　There are mainly two categories of methods for detecting leaks in oil pipelines: direct detection methods and indirect methods. The direct method involves using detection elements pre-installed outside the pipeline (such as leak detection cables or oil-sensitive elements) to directly detect the leaking medium. This method can detect minor leaks and locate them, but it requires installation alongside the pipes during their construction. The indirect method involves inferring the occurrence of a leak by detecting changes in the operating parameters of the pipeline, such as pressure and flow rates. This method has lower sensitivity compared to the direct method, and it is suitable for detecting larger leaks (around 1%). Its advantage is that it can be installed without disrupting production after the pipeline is built, and it can be upgraded over time. 　High-precision pipeline leakage monitoring and location technology is an integrated technology that combines multiple disciplines. This system integrates infrasound pipeline leak location technology, GIS (Geographic Information System), and GPS (Global Positioning System). It is a comprehensive management platform based on GIS technology, suitable for applications over long distances, involving multiple pipeline sections, and in complex conditions. 　Based on a Geographic Information Management System (GIS), the system creates a visual production information management platform that enables centralized management and sharing of production data, making it suitable for the requirements of production operation management and safety management in pipeline management. 　The pipeline operation safety management and monitoring system, centered on the infrasound method, is responsible for detecting abnormal leaks in pipelines. This system monitors the operation status of pipelines in real time, providing 24/7 surveillance for theft and leaks. This technology features high monitoring sensitivity and positioning accuracy. 　A positioning and navigation system based on the GPS satellite positioning system can accurately guide managers to the scene of an incident quickly. 24/7 technical support ensures precise and rapid responses in emergency rescue operations in the field. It can maximize the quality and safety levels of on-site command and construction management. 　The Mobile/Serber (M/S) concept was introduced into the overall system framework design, establishing a brand-new system framework that combines C/S, B/S, and M/S. 　M/S is an abbreviation for Mobile/Serber; it represents an extension of the traditional C/S and B/S application architectures. By integrating cutting-edge technologies such as GIS, GPS, and GPRS/CDMA, it extends the applications of GIS from wired to wireless environments, from indoor to outdoor areas, and from desktops to handheld devices. This enables GIS-based information services to be utilized at the site of work, serving not only decision-makers in management but also directly supporting actual production activities. 　Infrasound technology is a new type of monitoring technique that has recently been introduced in China for pipeline leakage detection; it was first used in the monitoring of typhoons, tsunamis, earthquakes, volcanic eruptions, nuclear explosions, and other such phenomena. Due to the characteristics of infrasound, such as its long propagation distance and strong penetration ability, this technology is widely used for monitoring distant explosive events. The principle behind using this technology for pipeline leakage detection is to monitor the infrasound waves generated when the fluid inside the pipe breaks free from the constraints of the pipe walls. In practice, the properties of these waves are hardly affected by noise present in the pipe, their propagation speed remains constant, and the signals can be transmitted clearly to the remote receiving unit, thereby facilitating accurate location. Therefore, a monitoring system incorporating this technology can accurately locate the leak site. 　The infrasound pipeline leakage detector uses an electroacoustic transducer with a primary meter’s dynamic response, and capable of setting its range according to the dynamic changes in the pipeline, to detect the infrasound waves generated by the instantaneous physical disturbances in the medium caused by leaks during pipeline operation. The instrument is installed at the end of the pipeline and detects the time difference between the sound waves caused by the leak and those that reach the end of the pipeline; this time difference is timed using GPS, thereby allowing the precise location of the leak to be determined. 　This system uses a unique electronic map interface as the basic operation interface for data visualization management, providing vivid data services for production managers and offering strong technical support for the promotion and application of computer information management technologies. 　 This system can be integrated organically with production database systems, enabling interactive data queries and achieving visual management of production data. Various production management data for any facility can be managed through the management interface, facilitating users’ daily management and usage habits*. 　As proven through practical testing, a high-precision pipeline leakage monitoring and alarm positioning system that combines a management center platform, infrasound pipeline leakage detection and positioning technology, and GPS navigation technology is the best technical solution. The combination of these three components forms a complete pipeline safety management system. The intuitive human-machine interface facilitates operators’ work and enables immediate access to information regarding the location of leaks. The accurate and rapid alarm system ensures that leaks are detected as quickly as possible, while the GPS navigation system guarantees that all relevant departments and units can reach the scene in the shortest time possible. 　Construction of the high-precision pipeline leakage monitoring, alarm, and location system for the Gudong crude oil export pipeline began on January 8, 2006. All equipment was installed by January 17, and the initial setting of system parameters as well as the establishment of data models were completed by January 23; thereafter, the system entered the phase of operational scheduling and parameter calibration. 　The high-precision pipeline leakage monitoring, alarm, and location system is currently the only one in China that utilizes infrasound positioning technology with a precision within 100 meters. It represents a pipeline leakage monitoring technique that successfully integrates and applies GIS technology, GPS technology, wireless communication technology, and leakage location technology. It provides the most up-to-date technical solutions for field production management and emergency response support, in line with the development trend of enterprise informatization. However, due to the short integration time for this technology, coordination among the various modules still needs to be improved as individual technologies develop; currently, the overall system integration takes a relatively long time (about half a year). In-depth research is needed in areas such as the efficiency of geographic information processing, the adaptive adjustment of the system’s overall structure, advancements in communication modules, and alarms for minor leakage levels, in order to meet the on-site requirements for reliable and accurate systems as well as ease of use.