Abstract: The crude output of Northwest Petroleum Bureau has been growing rapidly in recent years, in which the heavy oil with high sulphur, high metal content and high density accounts for more and more proportions in output structures. But a heavy oil field's development today is restricted by becoming poor in oil product quality, lowering in oil price,resulting in increasing difficulty for such a crude sales or marketing. This paper analyzed Japopu's price system and international and domestic methods or principles for crude pricing, hence determined that Tahe heavy oil should belong to Duri crude in terms of international standard, and Gudao heavy oil in terms of domestic standard; its agio value should be in accordance with the Tarim's. Meanwhile, the paper calculated quality difference value of Tahe heavy oil, based on which the price level for it and more reasonable blending and exchange program are finally and rationally determined.

Key words: Tahe oilfield, heavy oil, oil price, agio, relative price, density