If there is hydrocarbon in the formation, an abnormal value will occur in the low frequency part of the amplitude spectrum ratio eurve o On the contrary, when no hydrocarbon exists in the formation there will be no abnormal value on the curve.

• 当地层含有油气时,在振幅谱比曲线的低频部分就出现异常值; 反之,不含油气时,就不出现振幅谱曲线异常。