Distributed Temperature Sensing for Erosion Detection and DoC Estimation: The Peru LNG Experience in Ayacucho and Ica Departments

2021 ◽  
Author(s):  
Fabien Ravet ◽  
Christian Silva ◽  
Rodolfo Gil ◽  
Etienne Rochat ◽  
Simon Maguire
Keyword(s):  
Thermal Analysis ◽  
Sand Dune ◽  
Fiber Optic ◽  
Time Lag ◽  
Temperature Sensing ◽  
Economic Consequences ◽  
Burial Depth ◽  
Distributed Temperature Sensing ◽  
Geotechnical Monitoring ◽  
Dune Migration

Abstract Pipelines often cross challenging terrains where natural hazards are the main risk for their integrity. Environmental conditions can also worsen over the infrastructure lifetime. To reduce the risk of disasters, integrity programs are developed and require tools for early detection of threats that can lead to a failure with dramatic social, environmental and economic consequences. Fiber optic based Geotechnical Monitoring System (GMS) have been used and implemented as an efficient prevention tools of these programs. As a good example, GMS is successfully in operation to detect landslides using Distributed Strain Sensing along the Sierra section of the Peru LNG pipeline since 2010. The continuous operation of the GMS also revealed that infiltration, erosion and sand dune migration can be detected using Distributed Temperature Sensing (DTS). First, hydraulic erosion was evidenced in the Sierra region. More recently, events whose origin is eolian erosion and sand dune migration have been identified. A thermal analysis was then conducted to analyze the measured thermal signatures of the detected event. It revealed that the DoC (Depth-of-Cover) can be computed from the temporal response of the fiber optic cable. The time lag between ambient temperature and temperature of the cable directly relates to its burial depth. The obtained data are compared with site inspection observation which confirm the validity of the DTS approach. The method, combining DTS measurements on existing communication cable with thermal analysis, offers the ability to monitor erosion related geohazards in both Sierra and desert sections of the pipeline. The results of the presented work illustrate the potential value of fiber optic sensing to mitigate geohazard risks. It not only enhances the efficiency of the integrity program detecting and localizing threats, it also improves and rationalizes the maintenance activities as focused surveys can be conducted.

Sand Dune Migration Monitoring for Pipeline Hazard Risk Mitigation: The Peru LNG Coastal Section Case

2020 ◽  
Author(s):  
Fabien Ravet ◽  
Christian Silva ◽  
Rodolfo Gil ◽  
Simon Maguire ◽  
Etienne Rochat
Keyword(s):  
Early Detection ◽  
Natural Hazards ◽  
Sand Dune ◽  
Fiber Optic ◽  
Risk Mitigation ◽  
Third Party ◽  
Transport Systems ◽  
Geotechnical Monitoring ◽  
Dune Migration ◽  
Hydrocarbon Transport

Abstract Pipelines often cross challenging terrains where natural hazards are the main risk for their integrity. Environmental conditions can also worsen over the infrastructure lifetime. To reduce the risk of disasters, integrity programs are developed implementing tools for early detection of threats that can lead to a failure with dramatic social, environmental and economic consequences. Fiber optic (FO) monitoring solutions have been widely used and implemented as one of the most efficient prevention tools of these programs. These solutions include geotechnical monitoring, third party intrusion detection and eventually small or pinhole like leak detection. FO based geotechnical monitoring has been successfully operated along the Sierra section of the Peru LNG pipeline since 2010, detecting minor landslides and erosion events. It has also been implemented along other hydrocarbon transport systems to allow the early detection of such events. However, these natural hazards are not the only ones threatening the pipeline. In fact, the coastal section experiences other phenomenon such as sand dune migration and eolian erosion that put the pipeline at risk. Recently, the FO monitoring was extended to the coastal region using the existing communication fiber optic cable to sense temperature changes. Very localized events are thermally detected, their spatial and temporal signature analyzed. The comparison of this data with thermal models identified sections that are close to be exposed or whose soil cover is less than 50cm over a spatial extension that does not exceed a couple of meters. Depth of cover of 10 to 30cm is estimated from such analysis. These results are confirmed by past and ongoing site inspections. Such positive results again illustrate the potential value of fiber optic sensing to mitigate geohazard risks. It not only enhances the efficiency of the integrity program detecting and localizing threats, it also improves and rationalizes the maintenance activities as focused surveys can be conducted.

scholarly journals Thermodynamics of a fast-moving Greenlandic outlet glacier revealed by fiber-optic distributed temperature sensing

2021 ◽  
Vol 7 (20) ◽  
pp. eabe7136
Author(s):  
Robert Law ◽  
Poul Christoffersen ◽  
Bryn Hubbard ◽  
Samuel H. Doyle ◽  
Thomas R. Chudley ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Basal Layer ◽  
Temperature Sensing ◽  
Distributed Temperature Sensing ◽  
Catchment Scale ◽  
Outlet Glacier ◽  
Coarse Spatial Resolution ◽  
High Vertical Resolution ◽  
Fast Motion ◽  
Strain Heating

Measurements of ice temperature provide crucial constraints on ice viscosity and the thermodynamic processes occurring within a glacier. However, such measurements are presently limited by a small number of relatively coarse-spatial-resolution borehole records, especially for ice sheets. Here, we advance our understanding of glacier thermodynamics with an exceptionally high-vertical-resolution (~0.65 m), distributed-fiber-optic temperature-sensing profile from a 1043-m borehole drilled to the base of Sermeq Kujalleq (Store Glacier), Greenland. We report substantial but isolated strain heating within interglacial-phase ice at 208 to 242 m depth together with strongly heterogeneous ice deformation in glacial-phase ice below 889 m. We also observe a high-strain interface between glacial- and interglacial-phase ice and a 73-m-thick temperate basal layer, interpreted as locally formed and important for the glacier’s fast motion. These findings demonstrate notable spatial heterogeneity, both vertically and at the catchment scale, in the conditions facilitating the fast motion of marine-terminating glaciers in Greenland.

Measuring Artificial Recharge with Fiber Optic Distributed Temperature Sensing

Ground Water ◽  
2012 ◽  
Vol 51 (5) ◽  
pp. 670-678 ◽  
Author(s):  
Matthew W. Becker ◽  
Brian Bauer ◽  
Adam Hutchinson
Keyword(s):  
Fiber Optic ◽  
Artificial Recharge ◽  
Temperature Sensing ◽  
Distributed Temperature Sensing

Assessment of detection limits of fiber-optic distributed temperature sensing for detection of illicit connections

2013 ◽  
Vol 67 (12) ◽  
pp. 2712-2718 ◽  
Author(s):  
Jaap Nienhuis ◽  
Cornelis de Haan ◽  
Jeroen Langeveld ◽  
Martijn Klootwijk ◽  
François Clemens
Keyword(s):  
High Frequency ◽  
Fiber Optic ◽  
Detection Limits ◽  
Temperature Sensing ◽  
Distributed Temperature Sensing ◽  
Monitoring Equipment ◽  
Sewer Systems ◽  
Set Up ◽  
Frequency Temperature ◽  
Storm Sewer

Distributed temperature sensing (DTS) with fiber-optic cables is a powerful tool to detect illicit connections in storm sewer systems. High-frequency temperature measurements along the in-sewer cable create a detailed representation of temperature anomalies due to illicit discharges. The detection limits of the monitoring equipment itself are well-known, but there is little information available on detection limits for the discovery of illicit connections, as in mixing of sewers, and attenuation also plays an important role. This paper describes the results of full-scale experiments aiming to quantify the detection limits for illicit connections under various sewer conditions. Based on the results, a new monitoring set-up for (partially) filled sewer conduits has been proposed.

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