Abstract: Normalized full gradient of gravity anomalies can be used to find the location of source and inspect hydrocarbon structure because of its characteristic of “one less value between two high values”. Traditionally, В. М. Березкин method and Fourier transform were used primarily, but using DCT to calculate normalized full gradient of gravity anomalies was a new method. The authors presented gravity anomalies conversion formula based on DCT, in succession studied G_H field characteristics of these models that include infinite horizontal cylinder, symmetricaldensity spherecoronal and asymmetricdensity oil storage spherecoronal. These experiments had proved that the more was the depth, the smaller was the harmonic wave member, at the same time the singular point Maximum moved downwards and had linear attenuation. G_H field contour line of asymmetricdensity oil storage spherecoronal had presented typical characteristic of “one less value between two high values”. G_H field calculated by DCT has excellent stability and could enhanced the depth of downward continuation.

Key words: normalized full gradient of gravity anomalies, DCT, harmonic wave member, location of source, hydrocarbon structure