Oil & Gas Product News, 2012-12-17
The last thing pipeline and resource companies need is an equipment failure that could cost hundreds of thousands of dollars in lost production, wreak havoc on the environment and result in skyrocketing legal fees. But such mishaps can happen, in particular when pipelines and related structures such as pump shacks and compressor stations are located in highly sensitive areas such as unstable hillsides, marshes, bogs, swamps, river crossings and steep grades.
The Distance Reading Acquisition Module (DRAM), developed by a Vancouver company and in use in Alberta and Newfoundland, is designed to overcome these and other design and construction challenges and keep pipelines and associated equipment running smoothly.
“DRAM provides clear and unassailable evidence that pipeline operators have taken real, concrete steps to mitigate risks – real or perceived – associated
with the use of pipelines to transport vital materials, and the risks that such infrastructure might suffer a failure leading to environmental damage or other consequences,” says Iain Weir-Jones, president of Weir-Jones Engineering Consultants, which designs proprietary monitoring and analytical systems.
“Since such failures rarely happen instantaneously, vigilant monitoring is the only safeguard that allows the operator to make informed decisions with the benefit of early awareness and operational response,” he adds.
The Weir-Jones system is being used by pipeline and oil companies in Alberta and a public utility in Newfoundland & Labrador.
As the first technology of its kind in the world, according to its creators, DRAM provides three key advantages over previous-generation technologies that monitor the structural integrity of oil and gas pipelines and enhance the environmental safety of pipeline operations.
It enables operators to access real-time data in their pipeline operations centre, providing superior visibility and enabling rapid response to changing conditions, which was not previously possible.
A DRAM is an aggregation and transmission node, buried in situ at a monitoring point on a pipeline that captures data from up to 16 discrete sensor inputs. These sensors can include strain gauges, piezometers, inclinometers, displacement transducers or other sensors with analog/digital outputs.
Typically the sensors are interrogated periodically and their average outputs are stored as a single sample. Therefore, local variance from one reading to another cannot disproportionately skew the results observed by monitoring personnel, and the incidence of false positives or false negatives is greatly reduced.
Under normal circumstances, a channel is sampled at a rate of 2000 sps and the sampling duration is defined by the operator at the time of commissioning. Currently, a sampling duration of 125 msec is used, which allows the averaging of 250 readings.
A DRAM is assigned a unique address and communicates to a head end unit (HEU) over a dedicated cable that provides both power and data signals. The DRAM may be deployed at spacings between five or 500 metres of pipeline. Higher spacing densities will typically be adopted when assessing the behaviour of over or underbends, or where other structural features are present such as tie downs or expansion structures.
Conversely, long, near horizontal sections of pipe may see a significant reduction in DRAM density unless geotechnical risks such as liquefaction sensitive soils due to seismic loading are deemed to exist.
DRAMs are connected via a passive serial connection to the main backbone cable, which is protected from vandalism or environmental damage because it is attached to, and buried with the pipe, either secured directly or contained within protective conduit.
There are three primary benefits to DRAM as compared to legacy pipeline monitoring systems using intermittent manual readings. All of these benefits can be realized using a completely non-intrusive methodology that can be located in hostile or inaccessible areas, underwater or through any other type of terrain.
The essential value of real-time monitoring is therefore one of enabling the pipeline operator to implement a standard library of response processes when certain conditions are detected on one or more DRAMs. This can be achieved without any increase in staffing because the data presentation software (also provided by WJE) provides the triage and discrimination functions necessary to highlight only when anomalous conditions are present. Therefore the operator may be confident that data is being archived in a non-repudiable repository, and that whatever trigger conditions are desired can be unequivocally associated with an operational response procedure. These, in turn, can be measured for performance against target as part of standard operational audits.
Real-time monitoring of critical infrastructure is no longer a nice luxury; it is essential not only for operational performance management, but also as part of the broader Corporate Social Responsibility strategy, with all its attendant public relations implications.