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ABB controls pumps 25 miles out and 1,000 ft under the North Sea

  • March 03, 2009
  • ABB
  • Case Study

Summary

March 3, 2009 - An innovative, ABB-designed system that uses an underwater cable to connect a pump motor on the floor of the North Sea to a frequency converter on an oil platform 31 kilometers away has passed a string test for the Tyrihans oil field, off the coast of Norway. A general practice of the oil and gas industry is to verify the operation of equipment and systems before installation by conducting a ‘string test demonstration’ at the factory that simulates site conditions. Despite the technical challenges, the ABB system passed with flying colors. "In the world of technology, frontiers are made to be broken," commented ABB project manager Ole Meyer in Bergen, Norway, who worked on the project for more than two years. Production at the Tyrihans oilfield will employ five subsea skids installed on the seabed 300 meters (1,000 feet) underwater. One of them will use a 2.5-megawatt (MW) pump motor to inject raw seawater into the oil reservoir, raising pressure in the field to facilitate oil extraction. Tyrihans will deliver oil and gas by pipeline to the existing Kristin oil and gas platform 31 kilometers away. An ABB ACS1000 frequency converter installed on the platform will ensure the pump motor at the extraction site runs at optimal voltage. The problem is motors and converters are usually in the same room, not separated by 31 kilometers of open sea and a 300-meter dive to the seabed. To connect them ABB engineers had to stretch the technology to its limits. “We were really challenged,” said Meyer. “It's a world record, as far as we know.” Due to come onstream in 2009, the Tyrihans oil and gas field is one of the biggest offshore development projects on the Norwegian continental shelf in recent years, and installing the right electrical equipment in the field is essential to its success. A frequency converter is an electronic device that is often used to control the speed or torque of AC motors in pump or fan applications, achieving significant energy savings. It will also ensure the pump motor on the injection skid gets safe, high quality power and stays in peak working order underwater. The distance separating motor and converter meant ABB had to carry out extensive dynamic simulations to determine how the electrical system would behave. Simulations showed that it was possible to meet the customer's technical requirements, and also supplied important input for the design of additional equipment ABB is supplying to this project, including special transformers, control software for the frequency converter and system controller software. ABB in Bergen collaborated closely with colleagues in Turgi, Switzerland (for the frequency converter), and ABB in Vaasa, Finland (for the topside and subsea transformers). In addition to the unusual pump motor-converter connection, ABB is also supplying the biggest subsea transformer it has ever delivered for the injection skid on the sea floor. For the Kristin platform, ABB will supply specially designed transformers, frequency converters and a controller with newly developed software to power subsea motors, and ensure optimal operation of the injection pumps. The subsea cable and platform equipment will be installed in 2009-2010. ABB is a leader in power and automation technologies that enable utility and industry customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in around 100 countries and employs more than 120,000 people. Facts and figures:
  • StatoilHydro is the operator and biggest stakeholder of Tyrihans, which is one of the biggest developments on Norwegian continental shelf in recent years
  • The Tyrihans subsea field holds 176 million barrels of oil and 30 billion cubic meters of gas.
  • The field consists of five subsea templates: four for production and gas injection, and one for raw seawater injection
  • Pumps will suck in 14,000 cubic meters of untreated seawater each day, and inject this and gas into the reservoir to create optimal pressure
  • The wellstream will be transferred to the Kristin platform via a 43-kilometer long electrically-heated pipeline
  • The field is scheduled to come on stream in 2009 Learn More

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