Study of flow units and electrofacies in the Mishrif Formation (upper part of Sarvak Formation) and estimation of reservoir zone in Sirri Oilfields located in Persian Gulf

The upper part of the Sarvak Formation is one of important hydrocarbon reservoirs in the Middle East and Persian Gulf. This part of the Sarvak Formation is equivalent to the Mishrif Formation (with mid-Cenomanian age) in Persian Gulf and neighboring countries. In this study, investigation of a set of well log data and their clustering based on mathematic and statistical rules resulted in determination of reservoir electrofacies (EF1, EF2, EF3 and EF4) for the Mishrif Formation in three wells of Sirri fields in the Persian Gulf. Then, by using of core porosity and permeability data and flow zone indicator (FZI) method, flow units (A, B, C and D) were identified. With integration of the results from these two methods, reservoir zone thickness of Sirri Esfand, Dena and Civand 62 ± 0.5m, 91± 0.5m and 39 ± 0.5m was determined, respectively. Finally, by utilization of water saturation factor, hydrocarbon column thickness in Sirri Esfand, 34.5m; in Sirri Dena, 8.5m and in Sirri Civand, 39.5m was calculated. Based on these results, hydrocarbon column thickness from Sirri Esfand to Dena decreases, and it increases from Sirri Dena towards Sirri Civand.