Heavy acidic crude oils create challenges for all key operations from well to refinery. The Grane crude oil is heavy with API of 18,7 and has a high viscosity and a high TAN, rather different from most other Norwegian crude oils. The Grane field was developed with a pipeline to the Sture terminal. This increased the market area and market flexibility as offshore loading operations were avoided. The pipeline has never created any production regularity problems, despite the high viscosity of the crude oil. The Grane crude oil is heated to 30-350 C at the terminal. The naphthenic character, the yield structure and the acidity of the Grane crude oil make coprocessing or blending with other, ideally paraffinic crude oils attractive, and Grane is a good feed for upgrading by either hydrocracking or by FCC. Grane has a TAN of 2,2 mg KOH/g, while the Naphtenic Acid Titration (NAT) method, which measures only the naphthenic acids, gives a value of 1,4 mg KOH/g. During the field development phase it became clear that marketing of Grane was going to be a challenge compared with the sweet North Sea crude oils Hydro had produced and been marketing. A strategy for marketing of Grane was established, based on building up Hydro in-house competence on all areas of relevance for refining of this type of crude oil, reducing the Grane initial marketing and pricing uncertainty. When Grane was introduced to the market, a price discount related to additional technical cost and market related factors had to be accepted, related to the fact that the refining properties of the oil have not been tested in large-scale operations. Since start-up we have been through periods with large price fluctuations, and the price discount compared with Brent has varied significantly, in the range 4 - 11 USD/bbl. The competence established through this project will be applied in all heavy, acidic crude oil Hydro projects, securing maximum value from these fields both for Hydro, partners and authorities involved in these projects.
Heavy acidic crude oils create challenges for all key operations from well to refinery. This paper will present how Hydro tackled the challenges related to transportation, marketing and refining of the Grane crude oil.
The Grane field was discovered in 1991 and the PDO recoverable reserves of approximately 700 million barrels will be produced over a 25 years period. A long-term oil production test of the Grane field was carried out in 1996. Detailed analyses were carried out on the well stream and the crude oil produced. The crude oil is heavy with API of 18,7 and has a high viscosity and a high TAN, rather different from most other Norwegian crude oils. The partner group decided to construct a 212 km long pipeline from the Grane field to the Sture crude oil terminal at the west coast of Norway.
