Abstract: Banghu-Zhouji syncline belt is the best source belt in Qianjiang sag with abundant hydrocarbon resources. Based on the theory of geothermal-geopressure system and observed temperature-pressure data from more than 90 wells, this paper analyzes the plane and section characteristics of the geothermal field, geopressure field and geothermal-geopressure system in Banghu-Zhouji syncline belt as well as the relationship between these characteristics and hydrocarbon distribution. The research shows that the high geothermal gradient in Banghu-Zhouji syncline belt is propitious to the maturity of source rocks and generation of hydrocarbons; the deep low overpressure could be as the important motivating force for petroleum migration; vertically, it has the characteristic of overpressure complex geothermalgeopressure system, but the vertical migration capacity of hydrocarbons is weaker, being dominated by short-range lateral migration; laterally, various oil-bearing reservoirs are mainly distributed in the areas with relatively low fluid energy, which is surrounding or adjacent to the areas with relatively high fluid energy.

Key words: geothermal field, geopressure field, geothermal-geopressure system, oil-gas distribution, Banghu-Zhouji syncline belt