High-Sensitivity Real-Time Tracking System for High-Speed Pipeline Inspection Gauge

Abstract

Real-time tracking of pipeline inspection gauges (PIGs) is an important aspect of ensuring the safety of oil and gas pipeline inline inspections (ILIs). Transmitting and receiving extremely low frequency (ELF) magnetic signals is one of the preferred methods of tracking. Due to the increase in physical parameters of the pipeline including transportation speed, wall thickness and burial depth, the ELF magnetic signals received are short transient (1-second duration) and very weak (10 pT), making the existing above-ground-marker (AGM) systems difficult to operate correctly. Based on the short transient very weak characteristics of ELF signals studied with a 2-D finite-element method (FEM) simulation, a data fusion model was derived to fuse the envelope decay rates of ELF signals by a least square (LS) criterion. Then, a fast-decision-tree (FDT) method is proposed to estimate the fused envelope decay rate to output the maximized orthogonal signal power for the signal detection through a determined topology and a fast calculation process, which was demonstrated to have excellent real-time detection performance. We show that simulation and experimental results validated the effectiveness of the proposed FDT method, and describe the high-sensitivity detection and real-time implementation of a high-speed PIG tracking system, including a transmitter, a receiver, and a pair of orthogonal search coil sensors.

Improving the Design Approach to Developing Through-Metal Communications for Use in Subsea Pipeline Robots

“…The ubiquitous use of subsea pipelines in the transport of oil and gas products over long distances is inevitable as they are more reliable, energy-efficient and cost-effective compared with other methods such as maritime transportation [1]. To transport oil and gas products, subsea pipelines are spread over thousands of miles, located beneath or over the seabed, crossing mudbaths, shallows or deep oceans while carrying highly inflammable and explosive materials.…”

“…For instance, streaming product chemistry can lead to corrosion of the pipe's internal surface. Accumulation of sedimentary deposits, left from product impurity, and rust deposits, caused by pipeline corrosion, can also internally obstruct the pipeline [1]. Both external and internal defects can result in pipe-wall damage, rupture and product leakage which eventually lead to oil spillage and environmental pollution.…”

“…In the oil and gas industry, and drinking water/sewer transportation system minimal structural, non-destructive evaluation (NDE) of pipes is widely undertaken using Pipeline Inspection Gauges (PIGs) [1]. In essence, a PIG, as shown in Fig.…”

“…Retrieving these robots can also be very dangerous; if the pipeline operator opens the PIG receiver before the robot has been fully reached there, it will be shoot out of the trapper with high speed. Such challenges potentially can damage the robot itself or result in human injuries; hence, PIGs must be tracked/localised while inside the pipeline [1]. One of the other challenges during PIG running is the inspection's lengthy data-processing time, which can significantly affect detecting defects in their early stages.…”

“…to in-pipe robot reduce the PIG's operation distance. In addition, tethered cables restrict the PIG mobility as they can easily tangle during the robot movement and lead to PIG stall inside the pipe [1], [8], [9]. Therefore, an effective PIG running demands duplex wireless signal communication with the inpipe robots.…”