Pipelines: SNAM Rete Gas - Gas pipeline monitoring

Case study: SOFO, ADAM, DiTeSt System

Pipeline distributed strain
monitoring
DiTeSt compatible SMARTape and
SMARTcord

Project Description

Summary: 500 meters of a buried, 35 years old gas pipeline, located near Rimini, Italy, lie in an unstable area. Distributed strain monitoring could be useful in order to improve vibrating wire strain gauges monitoring system, actually used in the site.

Clients: Snam Rete Gas (ENI Group)

Place: Verucchio (RN) (Italy)

Period: 2003 - 2003

Installation: ENI with SMARTEC support

Structure's short description: The landslide progress with time and could damage pipelines up to be put out of service. Three symmetrically disposed vibrating wires were installed in several sections at a distance typically of 50/100 m chosen as the most stressed ones according a preliminary engineering evaluation. These sensors were very helpful, but could not fully cover the length of the pipeline and only provide local measurements.

Aim of monitoring: Three types of sensors were used: SMARTape, SMARTcord and Temperature Sensing Cable. The SMARTape sensor consists of sensing optical fibre integrated into the 200 micrometers thick fibre-reinforced composite tape. Three parallel lines constituted of five segments of this sensor were installed over whole concerned length of the pipeline. The lengths of segments were ranged from 71 m to 132 m, and the position of the sensors with respect to the pipeline axis were at 0?, 120? and ?120? approximately. The strain resolution of the SMARTapes is 20 micro-strains, with spatial resolution of 1.5 m (and an acquisition range of 0.25m) and provides the monitoring of average strains, average curvatures and deformed shape of the pipeline. The SMARTcord sensor consists of sensing optical fibre integrated into the fibre reinforced plastic cord with a diameter of 6 millimetres. A single 500 meters long sensor was installed in the soil, below the pipeline in order to monitor the strain changes in the soil. The resolution of the SMARTcord is the same as for SMARTape. These measurements have been correlated with the SMARTape measurements in order to evaluate the strain transfer from the soil to the pipeline. The Temperature Sensing Cable was installed onto the upper line (0?) of the pipeline in order to compensate the strain measurements for temperature. The temperature resolution of the sensor is 1?C with the same resolution and acquisition of the SMARTape. All the sensors are connected to a Central Measurement Point by means of extension optical cables and connection boxes. They are read from this point using a single DiTeSt? reading unit. Since the landslide process is slow, the measurements sessions are performed once a month. In case of earthquake a session of measurements is performed immediately after the event. All the measurements obtained with the DiTeSt? system will be correlated with the measurements obtained with vibrating wires.

Number of sensor: 23

Main Results: At present stage, all the sensors are successfully installed and the first measurement session was performed. A gas leakage simulation was performed with success using the temperature sensing cable.

View to pipeline with SMARTapes installed on the first segment

Sensor installation plan

Bibliography:

Overview of fibre optic sensing to structural health monitoring applications , D. Inaudi, ISISS'2005, International Symposium on Innovation & Sustainability of Structures in Civil Engineering, Nanjing, China, November 20-22, 2005

Field Applications of Fiber Optic Strain and Temperature Monitoring Systems , D. Inaudi, B. Glisic, Opto-electronic Sensor-based Monitoring in Geo-engineering,Nanjing, P.R.China, November 23-24, 2005

Application of distributed Fiber Optic Sensory for SHM , D. Inaudi, B. Glisic, 2nd International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-2'2005), Shenzhen, China, November 16-18, 2005

Reliability and field testing of distributed strain and temperature sensors , D. Inaudi, B. Glisic, SPIE Smart Structures and Materials Conference in San Diego. 2006 February 27, March 2, 2006

Distributed Fiber optic Strain and Temperature Sensing for Structural Health Monitoring , D. Inaudi, B. Glisic, IABMAS'06 The Third Int'l Conference on Bridge Maintenance, Safety and Management, 16 - 19 July 2006, Porto, Portugal, 2006

Long-Range Pipeline Monitoring By Distributed Fiber Optic Sensing , D. Inaudi, B. Glisic, 6th International Pipeline Conference September 25 - 29, 2006, Calgary, Alberta, Canada, 2006

Health monitoring with optical fiber sensors: from human body to civil structures , ?ic Pinet, Caroline Hamel, Branko Gli?ic, Daniele Inaudi, Nicolae Miron, 14th SPIE Annual Symposium on Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring, San Diego (CA), USA, 6532-19, 2007

Distributed Fibre Optic Sensing for Long-Range Pipeline Monitoring , Daniele Inaudi, Branko Glisic, The 3rd International Conference on Structural Health Monitoring of Intelligent Infrastructure - SHMII-3, November 13-16, on conference CD, 2007

Distributed Fiber Optic Sensors: Novel Tools for the Monitoring of Large Structures , Daniele Inaudi, Branko Glisic, Geotechnical News, Volume 25, Number 3, Pages 8-12, 2007

Pipeline Leakage Detection and Localization Using Distributed Fiber Optic Sensing , D. Inaudi, B. Glisic, A. Figini, R. Walder, Rio Pipeline Conference 2007, Rio de Janeiro, Brazil, October 2-4, 2007

Fibre Optic Methods for Structural Health Monitoring , Branko Glisic and Daniele Inaudi, Johh Wiley & Sons, Ltd, 2007