Development modeling of the Neft Dashlari field within the South Caspian Basin

Background. The paper examines the current state of development of the productive horizons within the South Caspian Basin, focusing on Block IV of the Neft Dashlari field. As one of Azerbaijan's largest offshore fields, Neft Dashlari possesses significant hydrocarbon reserves. This study systematizes extensive geological and field data to provide a reliable description of the field's geological and technological characteristics, including stratigraphy, tectonics, fluid hydrochemistry, and current reserve status.

Methods. The study is based on the analysis of historical production data since the field's discovery in 1949. Statistical and geological modeling was used to evaluate the 26 discovered oil-bearing layers. The research focuses on the distribution of industrially significant residual oil reserves within the upper and lower stages of the Productive Series (PS) sediments.

Results. Since the commencement of operations, cumulative production has reached 168,787.1 thousand tons of oil, 243,913.2 thousand tons of total liquid, and 13,090.4 million cubic meters of dissolved gas. Current annual production stands at 812 thousand tons of oil with an average water cut of 38.2 %. The average daily well yield is 7.2 tons of oil and 11.7 tons of liquid. The utilization rate of recoverable reserves is 87.3 %. The current oil recovery factor (ORF) is 0.440, while the ultimate ORF is estimated at 0.504. To maintain pressure and enhance recovery, water injection has been employed since 1953, specifically targeting the VII and X horizons, as well as the Fasila and Kirmaki suites of Block IV.

Conclusions. Development models for Block IV indicate that micellar flooding is a highly effective Enhanced Oil Recovery (EOR) method for extracting residual reserves. The use of microemulsions allows for the revitalization of flooded layers, potentially increasing the ORF to 50–60 %. Furthermore, it is recommended to increase reservoir sweep efficiency, reduce water cut, and optimize the well stock through sidetracking (drilling of lateral boreholes). To further enhance recovery at the final stage of development, the implementation of Water-Alternating-Gas (WAG) injection and the transfer of flooded wells to higher productive horizons are proposed.