关键词: 碳酸盐胶结物, 成因, 长8 油层组, 鄂尔多斯盆地

Abstract:

The second member of Shanxi Formation consists of a suite of thin interbedded sandstone, mudstone and coal bed in eastern Ordos Basin. It has strong reservoir heterogeneity and is obviously influenced by the acceptable spacesedimentary supply ratio in base level cycle process. Based on the division and contrast of the different base level cycles of the second member of Shanxi Formation, the high resolution sequence stratigraphic framework is set up. Through analyzing the relationship between the cycle process of short-termbase level and physical properties of the reservoir, three reservoir heterogeneity models of reservoir physical properties are established. The macroscopic heterogeneities of the middle-term base level cycles are described by means of the parameters such as sand density,drilling ratio and permeability variation coefficient. The result shows that the reservoir heterogeneity of the middle-term cycles formed in the early and middle period of the rising of the long-term base level cycle is weak, and it is strong from the late period to declining period.

Key words: carbonate cements, origin, Chang 8 reservoir, Ordos Basin