The controlling factors and abnormal forming mechanisms of geothermal field in Biyang depression

Abstract：The origin and controlling factors of geothermal field and geothermal abnormity were investigated through analysis and calculation of geothermal data in Biyang depression.The results indicate that the geothermal field is controlled by geologic structure.The direction of geothermal abnormal zone reflects the basic outline of regional structure.Rock properties influence on the distribution of geothermal field.Sandstone is of high thermal conductivity and low thermal gradient.Mudstone is of low thermal conductivity and high thermal gradient.Hydrodynamism is an important factor of the formation in abnormal geothermal field, where the strong alternating zone is always negative abnormal, and the discharge area or fracture zone is always positive abnormal.The geothermal abnormity is formed by released heat of hydrocarbon, accumulating heat of a trap and overpressure in a reservoir, which coincides with oilfields distribution.

Keyword：geothermal field;controlling factor;geothermal abnormity;forming mechanism;Biyang depression;