The Talu Sandstone is the major producing formation in the Hsinchu-Miaoli area where is the most important oil and gas fields in Taiwan. In this study the Talu Sandstone is selected as the target and attention is focused on the diagenetic effect on reservoir qualities. All analytical results can be used to delineate the reservoir qualities of the major structures which are favour to the exploration and exploitation of hydrocarbons in this area.