StatoilHydro extends wireless flow monitoring

London - StatoilHydro is employing wireless flow monitoring to increase production on the company’s Gullfaks offshore platforms in the northern part of the Norwegian North Sea. The This installation system is based on Emerson Process Management’s Smart Wireless network and follows the application of same technology on StatoilHydro’s Grane platform.

The oil and gas operator had occasionally been losing flow from the producing wells at its Gullfaks A, B and C platforms, due to a loss of wellhead pressure. The loss of flow was very difficult to detect due to there being no existing flow-metering devices installed within the well pipes. Installing such devices for this application was not practical as this would require a complete shut down of production, which would be far too expensive in terms of lost throughput.

Engineers considered introduced new sensors but faced problems with connecting them back to the control room. The wellhead was already a very crowded area and for safety reasons it must be kept as clear as possible. The introduction of additional equipment such as new cabling, cable trays and junction boxes was not possible.

StatoilHydro had previously detected loss of flow by sending an operator to the wellhead where they placed their hand on the pipe to feel whether there was a difference between the pipe temperature and the ambient temperature. Typically well fluid is 60° C so the pipe feels warm, but should flow be interrupted it slowly drops back to the ambient temperature. Readings were taken only at the start and the end of a shift, so a loss of flow could go undetected for long periods and production lost.

Seeking to automate the monitoring so as to provide real-time data, while also reducing personnel presence in hazardous areas, StatoilHydro initially implemented a pilot installation on the Gullfaks A, B C platforms. Emerson's Rosemount 648 wireless temperature transmitters were installed to indirectly indicate flow on lines at each of forty wells. The wireless devices are used to transmit data from clamp-on temperature sensors mounted on the surface of the flow pipes.

“Because there is daily radio communication within the well area it is essential that the wireless field network can coexist without any reduction in performance,” continued said Anders Røyrøy, project manager, research development projects, StatoilHydro Norway.

The wireless devices now transmit readings every 30 seconds back to the wireless gateway, which is hardwired straight into the existing control system to provide operators with the real time information they need to react quickly to any change in flow.

The wireless transmitters have enabled the quick and reliable detection of lost flow, and the immediate action to re-establish flow has increased production significantly. said Tormod Jenssen, staff engineer, Plant Integrity, Gullfaks field.

StatoilHydro has now implemented additional Smart Wireless devices on Platforms A, B and C, bringing the total to 90 wireless transmitters covering all production flow lines at Gullfaks.