HART Keeps Ormen Lange Gas Flowing

Meeting the challenge for less
When designing the plant, StatoilHydro faced several constraints. One was the remote location, second was the occasional harsh weather, and a third was the size of the facility. As finally built, the on-shore plant is quite large: one square km, with a main control room and 10 substations.

Mr. Ramberg recalls the technology selection process. The designers knew that given the constraints, predictive diagnostic functions were particularly important. With that capability, the health of a valve or other component could be gauged and maintenance could be done as needed. Valves wouldn’t be changed out too soon, which would waste money. Nor would they be changed out too late, potentially jeopardising operations.

There were other benefits to having a wealth of diagnostic information. The right data can identify the root cause of a problem. It might then be possible to correct the issue remotely, meaning fewer personnel would be exposed to harsh weather and possibly dangerous conditions. What’s more, the collection of data could, over time, lead to the elimination of some problems as root causes were identified and fixes implemented.

Because of the advantages of a communication rich approach, the company selected HART Communication technology to deliver the device diagnostic information it was seeking. The finished plant has about 1,400 HART-enabled field devices connected on-line, full time. Of these, about 350 are valve positioners, with most of the rest instrumentation transmitters. A handful of traditional 4-20 mA anti-surge valves are connected to HART multiplexers so that their data can be converted for communication.

Control is handled by an ABB system, with secondary controllers in the substations handling the interface between local devices and the plant-wide controller. As might be expected given the need for reliability, there are redundancies and intelligent approaches built into the setup, which aren’t always those typically thought of or used. For example, there’s a robust video conferencing capability so that experts from around the world can hold virtual meetings to help diagnose problems and propose solutions.

Operations begin
‘The startup was an activity going on for weeks, but the actual startup was when they opened the valve to the well. That happened the 13th of September 2007,’ says Mr. Ramberg.

He adds that HART technology helped the plant meet its commissioning schedule. With that, in many respects, his job is done. Starting in December, operation of the plant was taken over by project partner A/S Norske Shell, the Norwegian member of the Shell family.
Graham Baird, a condition monitoring engineer for A/S Norske Shell, is one of those responsible for monitoring the plant’s day-to-day operations and health. He’s had input in the design phase, particularly with regard to what’s needed for operational monitoring of intelligent field equipment condition.

While there hasn’t been a lot of operational data so far, what the HART-enabled technology has delivered is promising. He cites the control system’s asset optimising package and device manager. ‘Early indications are that these will give us a lot of useful actionable data, as they are online systems scanning the HART-enabled instrumentation continuously,’ he says.
With alert reporting activated, operators can prioritise, schedule, and track their efforts. Mr. Baird notes that troubleshooters have made fault diagnosis very quickly, enabling corrective action to be taken in a controlled manner. Often this has allowed fixes to be made directly to the root cause of the problem rather than a symptom.

There can also be synergies with other non-HART condition monitoring systems. For example, compressor performance can be influenced by surge valve conditions, instrumentation calibration, and so on. With more diagnostic data available, it’s possible to cross reference between systems to establish why equipment may not appear to be performing according to design. ‘All in all we get a much better overall view of the plant asset condition right now’ sums up Mr. Baird.

He explains that using HART technology and the wealth of diagnostic information it provides aligns with Shell’s Total Reliability Initiative. Getting a more informative picture helps plant operators rest easier at night, he says. ‘Having a large number of instruments and valves connected to HART-based systems for diagnostics can help us achieve a high availability for safety related instruments, critical process instruments and control valves. This gives plant operators confidence that they have properly operating control equipment.’ Individual wellheads and pumping stations are placed on the sea floor about 1000m deep. Thus, an intelligent application of HART technology coupled with the predictive diagnostic capabilities built into the system, should keep the Ormen Lange plant running in a cost-effective manner for years to come. 2007 HART Plant of the Year The Ormen Lange onshore facility received the 2007 HART Plant of the Year Award presented to end user companies in recognition of their ingenuity in applying HART technology. Award winners are plants that have taken the capabilities of HART instruments beyond configuration and calibration or are using the real-time diagnostics and process variables of HART-enabled devices to improve operations, lower costs and increase plant availability. ‘This plant was selected for its foresight and ability to build the infrastructure to take advantage of HART capabilities in their intelligent field devices,’ says Ron Helson, executive director of the HART Communication Foundation. ‘They’re very forward thinking and proactive when it comes to moving to a predictive maintenance strategy that will lower maintenance costs and improve plant reliability.’