Abstract:

Sandstones deposited in deltaic and coastal environments cover a wide range of sediment facies and geometries and constitute the majority of the producing hydrocarbon reservoirs in siliciclastic basins. In a delta, three dimensional geometries of sands are known to be complex and highly dependent on following factors: rivers, waves or tides affecting the delta based on the relative importance of their hydrodynamic processes. Therefore, it is necessary to have a good understanding whether the delta was fluvial, wave or tide dominated for accurate prediction of reservoir property and sand body geometries to optimize geological models. In the study area, the Lower Miocene sand reservoir was deposited in a deltaic environment with minor marine influence resulted from integration of seismic attributes and well data including core, high resolution biostratigraphy and well log data. The delta is characterized by mouth bar deposits formed during regressive phase and backfilled distributary channel deposits formed during transgressive phase. Its distributaries were filled with fining upward sands accompanied by relatively minor marine reworking and becomes increasingly marine upward