تفسير توالي پاراژنتيكي انيدريت هاي سازند گچساران در ميدان نفتي آب تيمور - جنوب غرب اهواز

Interpretation of Anhydrite Facies Paragenetic Sequence in the Gachsaran Formation at Ab-Teymur Oil Field-Southwest Ahwaz

The various morphology of Anhydrite in Gachsaran anhydrite facies at Ab-Teymure Oil Field indicate This facies underwent different degrees of diagenetic alterations during surface, shallow and deep burial diagenetic environments, diagenetic processes affected this anhydrite include nodule growth, pyritization, anhydritization, dissolution, silicification, compaction, recrystalization, pore filling, calcitization and anhydrite and gypsum veins. The succession of diagenetic processes and their paragenetic relationships within the Gachsaran anhydrite facies display a complex diagenetic evolution during syndepositional, early and late diagenetic stages. Many controlling factors such as, intensity of evaporation, sulfate reduction bacteria, depth of burial, tectonic activity, temperature variation, chemistry of brine and ground water, anhydrite preservation because of high stability in highly saline and O2 poor water, have been important factors influencing the anhydrite facies in Gachsaran Formation. The results of this can be used for evaluation of diagenetic processes in similar sulphate facies in evaporative basins, specially as a cap rocks of hydrocarbon reservoirs