Diagenetic environment is one of the vital factors to control pore types and evolutionary process of the red beds.On the basis of a great amount of microscopic thin section combining with ‘elemental geochemical index quantifiable forward modeling’ and ‘diagenetic product type and quantifiable inversion’

Temporal-spatial evolution of diagenetic environments are qualitatively analyzed in red beds of the eastern Dongying Sag

and diagenetically reformed pore volumes are quantitatively described.Additionally

pore evolution models under the control of multiple diagenetic environments are established in red beds.The results show that diagenetic environments in red beds can be divided into original alkaline environment and burial acidic environment owing to primary depositional environment

organic acid and hydrocarbon injection period at temporal dimension.On the plane view

with alkaline water released by saline lake areas and changes of organic acid concentration along with the migration distance

diagenetic environment can be divided into four parts from lake area to sag margin:moderate strong alkalinity-weak acidity

moderate-strong alkalinity-weak acidity

weak alkalinity-moderate-strong acidity

weak alkalinity-weak acidity.Due to the spatial variation of diagenetic environment

the degree of original pore reduction and secondary pore generation are obviously different in different tectonic positions

which in turn leads to diversified reservoir space types and significant porosity difference red beds in the eastern Dongying Sag.