The diagenetic reactions of Jurassic-Triassic successively deposited sandstone-mudstonesystem in North Tarim Basin were mainly controlled by temperature intervals. The concentration of organic acid in oilfield water reached the peak value when temperature was 90135C

and this resulted in the dissolution of aluminosilicate and carbonate minerals. Extensive dissolution of plagioclase is the main cause of abundant authigenic kaolinate and highsecondary porosity. The improvement of porosity was closely related to the physical properties of original reservoir.