Lithofacies analysis of the Productive Series deposits in the Bulla-Deniz oil and gas condensate field (Azerbaijan)

• Date: 2025
• Main Authors: Khalilova, Lala, Kerimova, Kifayet
• Format: Article
• Language: English
• Published: S. Subbotin Institute of Geophysics of the NAS of Ukraine 2025
• Subjects: sequence stratigraphy; non-anticlinal trap; system tract; depositional environment; reservoir; horizon
• Online Access: https://journals.uran.ua/geofizicheskiy/article/view/327141
• Journal Title: Geofizicheskiy Zhurnal

The study of the Bulla-Deniz Field by geological and geophysical methods began in the 1950-sand continues up today. Since the oil-and-gas bearing objects of the field have a complex geological setting at considerable depth, their penetration, sampling and development are one of the most important problems of today. Therefore, a detailed study of the geological structure of the field is very relevant. The object of our investigation is the Bulla-Deniz Field, located in the north-western part of the Baku Archipelago. Exploration works revealed here oil-and-gas condensate bearing successions of V, VII and VIII horizons of the Productive Series. The objective of the study was to refine the geological structure and depositional conditions of these Productive Series horizons as well as to assess their reservoir properties based on well log data. Sequence stratigraphy is an important method in geological and geophysical research. This method can be used to improve significantly the prediction of the studied fields, as well as to reveal unconventional reservoir types. The facies analysis, one of the stages of sequence stratigraphic analysis, is applied for studying the facies predictions from log data. Since the beginning of the oil production era, the main objects of hydrocarbon exploration have been medium and large anticlinal traps. These have been actively developed; as a result, their potential as primary exploration targets is being gradually exhausted. Therefore, the main exploration objects are non-anticlinal traps, low-amplitude uplifts, and stratigraphic wedges. The modern integrated approach allows tracing the conditions of the formation of sedimentary basins and improving the very understanding of sedimentation conditions. We applied to the sequence stratigraphic analysis, the Emery method, and the cyclostratigraphic analysis to the study area. Sedimentation conditions were established and analysed, and lithofacies analysis was carried out. Hydrocarbon-rich reservoirs were found to be predominantly in the low sea-level tract and, slightly less frequently, in the transgressive system tract. In most cases, deposits formed during the aggradation and retrogradation periods have good reservoir properties.