Abstract: Based on the classification of reservoir grade, the reserves fractal curves of 201 reservoirs in Raoyang sag are studied. The results indicate that in future exploration it is difficult to find reservoirs with more than 112×10⁴t reserves; the reservoirs with (28~112)×10⁴t reserves are of certain exploration potentials, and most reservoirs with less than 28×10⁴t reserves are to be proven. By calculating the fractal dimensions of reserves of pre-Paleogene, Shahejie formation, DONGying formation and Neogene reservoirs and counting fractal eigenvalues of reservoirs of every sequence, it is suggested that Shahejie formation is of the greatest exploration potential, followed by DONGying formation, Neogene and pre-Paleogene. However, there are more opportunities to find reservoirs with more than 30 ×10⁴t reserves in pre-Paleogene than that in Neogene. By comparison among fractal characters of spatial distribution of all reservoirs, pre- Paleogene reservoirs and Shahejie reservoirs, it is found that the whole fractal dimension (D) is much greater than layered fractal dimension, so the size of D only reflects the oil-bearing area, but it can not represent the size of reserves directly.

Key words: Raoyang sag, reserves scale, spatial distribution, fractal, fractal dimension