Controls on Reservoir Quality in the Early Triassic Kangan Formation, Iran

Controls on Reservoir Quality in the Early Triassic Kangan Formation, Iran

B. Esrafili-Dizaji, F. Kiani Harchegani, H. Rahimpour-Bonab and M.R. Kamali

The Early Triassic Kangan Formation is one of the most prolific gas reservoirs in Iran. The formation consists in two reservoir units: K2 and K1 in the area of investigation. Ten facies are distinguished in the Kangan Formation. These facies are interpreted as peritidal, lagoonal, shoal and fore shoal deposits. Two depositional sequences, Khuff sequence-2 (KS-2) and KS-1 are differentiated based on facies stacking patterns. Detailed diagenetic studies suggest that the Kangan sequence was exposed to early diagenesis after deposition. Two styles of early diagenetic processes are interpreted: dissolution with cementation (type A) and dolomitisation with anhydrite plugging (type B). Differences in early diagenesis are interpreted as a function of palaeosalinity on the platform. This in turn is controlled by relative sea-level fluctuations and palaeoclimatic conditions. The Kangan Formation is now buried at over 2.7 km and exposed to temperatures of about 100°C. This study indicates that the spatial and temporal development of fracturing and stylolites (types, diversity and frequency) are related to early diagenetic modifications. Our investigations conclude that the pattern and intensity of burial diagenetic and reservoir quality are mainly controlled by primary textural variation in the Kangan Formation.

موضوع: دانلودها، درباره نویسنده
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