As E&P companies battle against lower margins and a weak oil price, the cost-effective flow of hydrocarbons from reservoir to refinery has never been more important.

Yet one of the most significant threats to production today is that of sand erosion. All too often sand can clog production equipment, erode completion components and interfere with oil and gas infrastructure. Together, these can have a highly negative effect on production rates from the field.

The increase in aging oil and gas assets also has led to a renewed focus on sand monitoring. Such fields often have rising water production and more sand as well as increasing amounts of gas, leading to higher velocities and a greater risk of erosion damage from sand particles. Furthermore, with the need to make smaller fields more economically viable, predictive sand monitoring tools are crucial to ensure maximum returns from these fields’ production systems.

It’s against this backdrop that the monitoring of erosion on essential lines is vital as sand contributes to the failure of equipment and loss of containment as well as posing a risk to personnel and the environment. Operators today need access to a complete production system, delivering intelligent real-time information and operating alongside existing instrumentation. Are today’s sand monitoring systems rising to these challenges?

Evolution of sand monitoring technologies
The last few years have seen the emergence of acoustics and erosion-based sand sensors as a means of providing immediate and accurate responses to sand erosion. Such acoustic sensors use the acoustic energy generated by sand particles to calculate sand production in multiphase pipeline flows.

Many erosion-based sand monitoring technologies today also are based on the electrical resistance principle, where metal loss on the element is measured as increased electrical resistance in a sensing element exposed to sand erosion. Sand production rates can then be quantified by combining measured metal loss rates with average sand particle size and flow data.

Acoustic and erosion-based sand monitoring systems complement each other well. Acoustic monitors provide an immediate response to sand production. They are, however, complemented by intrusive sand/erosion probes that generate accumulated erosion data and are able to provide highly accurate measurements of the accumulated long-term effect of sands.

In addition, the field signature method, which measures corrosion or erosion directly on the pipe wall by detecting small changes in current flow due to metal loss, also can operate alongside sand monitoring.

Integrated wireless-based solution
For all these technology developments, however, there still remains a lack of integration across asset integrity management systems and a need to adopt ever more innovative digital and wireless-based technologies.

It’s for this reason that Emerson recently introduced the Roxar CorrLog and SandLog Wireless transmitters. The transmitters can be directly integrated within WirelessHART networks, a wireless sensor networking technology, to provide a complete asset integrity management system for operators. They are examples of how Emerson’s automation, digital and smart wireless
technologies can be combined with its Roxar corrosion and sand monitoring instrumentation to protect operators’ upstream and downstream assets.

The operating principles of the new probe are based on the already described electrical resistance corrosion probe technique, which relies on the erosive effects of sand particles on thin noncorrosive elements mounted on a probe inserted into the pipe. When combining measured sand/erosion rates with flow rates and assumed sand particle size, sand production can be quantified.

In this case, however, the transmitters are wireless-based, resulting in a significant reduction in installation costs compared to wired online systems and also allowing continuous online monitoring in previously inaccessible areas.

The system includes an up to 20-m (66-ft) cable between probe and transmitter. In this way, the system can be installed where it is most convenient for the user (in regard to maintenance and battery replacement, for example) as well as where it is most beneficial for wireless signal routing, thereby avoiding shadows where radio communications might be difficult.

The transmitters are also highly accurate and reliable and come with a low risk of signal loss in high-risk applications, with the sensitive sensors generating improved information for asset protection. Multielement sand/erosion probes also are incorporated within the Roxar SandLog transmitter to provide increased accuracy.

The raw data also can be transmitted to the Roxar Fieldwatch system for further analysis and verification. Through its flexible, scalable and distributed architecture, the Fieldwatch software combines real-time data with efficient online analysis and condition monitoring, allowing the user to have greater confidence in the veracity of the production data.

Probes from other manufacturers also can be read, and the direct transmission of metal loss values can be fed into Fieldwatch for improved monitoring and analysis. The transmitters also can be combined with any other Emerson WirelessHART products as they use the same gateway for data communications.

The result is a complete asset integrity system with direct integration to the WirelessHART network.

Industry collaboration
Stork, a global provider of knowledge-based asset integrity services, has recently successfully installed this sand-erosion monitoring solution on a major North Sea operator’s platform. The wireless devices will provide flexible, cost-effective and highly accurate online monitoring of sand erosion from the field in question, helping to extend equipment life and increase production from reserves.

The collaboration between Emerson and Stork also marks the first installation of the Roxar SandLog wireless monitors in the U.K. Continental Shelf and combines Stork’s monitoring solutions service offering alongside Emerson’s sand-erosion monitoring system.

Stork’s monitoring solutions department is positioned to deliver a range of traditional and advanced techniques for monitoring the rate of corrosion, erosion, stress, temperature, strain or intrusion on pipelines both on and offshore.

Stork’s monitoring solutions team provides operators with the means to monitor the rate of erosion on their assets, identifying and continuously reporting on areas of concern and enabling the planning of effective remedial action.

Increased control, insight
As operators look to deliver on the bottom line, incorporating greater intelligence and integration into their production and sand monitoring systems is becoming an even more pressing issue.

With highly sensitive and accurate sensors and direct integration to a wireless network and through the close collaboration between Stork and Emerson, it’s encouraging to see sand erosion monitoring technologies delivering greater insight and control over production operations.

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