Abstract:

Phenomena of same oil and gas filling conditions and obviously different oil-bearing were very common in clastic rocks of Tertiary system in Jiyang depression, which constrained seriously further exploration and evaluation of reservoirs. A vast amount of data of drilling and testing shows that porosity and permeability of clastic rock reservoir has an important effect on hydrocarbon accumulation, and there exists different porosity and permeability thresholds in different strata and different regions.The reservoir in different strata has different porosity structures and hydrocarbon accumulation resisting forces, and the oil and gas in different regions has different oil accumulation dynamic forces. Study on porosity and permeability threshold, which controlled by oil accumulation forces and reservoir porosity and permeability character, was used to interpret geologic phenomena of same hydrocarbon conditions and obviously different oil-bearing of sandstone, and was of practical importance for analysis and evaluation of petroleum accumulation.

Key words: clastic rock reservoir, hydrocarbon accumulation dynamic, porosity, permeability, threshold, Jiyang depression