Identification of maximum flooding surface at the Dashtak Formation and accordance with sea level change and eustacy

The Dashtak Formation in Zagros Basin is a Cap rock for the Dehram group reservoirs, is studied at three Wells (Aghar 1, West Aghar 1, Naura 1) for recognition of maximum flooding surfaces (MFS) in a sequence stratigraphic framework and relatives with sea level change, eustacy, subsidence and burial history. Data gathered from thin sections of cutting provided from this boreholes and geophysical logs including Gamma- Ray and Sonic logs. Depositional environment of Dashtak formation interpreted as an inner-middle homocline ramp. The formation consists of four depositional sequences. Each sequence begins with shoreface deposits and terminated with the shelf facies that represent characteristics of type R cycle with low TST thickness, MFS and HST intervals are more dominate. These sequences controlled by various factors including: 1) interplay between the rate of accommodation development and insitu sediment production, 2) amplitude and shape of relative Sea-Level curve in Triassic, 3) position in shorface-shelf system, 4) basin physiography, 6) climate driven environmental energy, 7) carbonate production vs. siliciclastic input, 7) eustacy and basin subsidence, 8) upward driven evaporates of diaprism. Postulated Sea-Level Curve and Eustacy for Dashtak formation is similar to those global curves inferred for Anisian-Norian time. Sediments deposited during Sea- Level fall pose good seal characteristics.