Refinement of the geological structure of the Bulla-deniz field at the surface of horizon VIII based on new seismic data

This article examines the geological structure of the Bulla-deniz field, specifically refining the geological configuration of the Pliocene, with a focus on the Upper Kirmaki Sand Suite, based on the latest geological and geophysical data analysis. The Bulla-deniz field’s geological structure comprises the Productive Series, Akchagyl and Quaternary deposits. In order to address specific geological issues related to hydrocarbon accumulation in deeper sediments, existing seismic data, particularly recent CDP data, from the Bulla-deniz area were reanalyzed using modern software. A new approach to interpreting the seismic data has been adopted, allowing for the correlation of the Upper Kirmaki Sand Suite. This horizon is characterized by more intense seismic reflections indicating alternating sand and clay layers. These seismic records are particularly prominent in cross-sections along the southeastern direction of the structure. According to the structural map of Horizon VIII, the Bulla-deniz field is an asymmetrical structure extending in the northwest-southeast direction, with a differentiated synclinal segment in the north. It was determined that the Bulla-deniz uplift is complicated by numerous longitudinal and transverse tectonic faults. Its southwest flank is characterized by a large-amplitude steep longitudinal fault, while the northeast flank has a gentler dip. The crest of the uplift is intersected by eight transverse tectonic faults. A buried volcano, likely associated with a high-amplitude longitudinal fault zone and extending up to the upper productive layers, has been observed within the Bulla-deniz uplift. Chaotic seismic reflections characterize this volcanic zone, with intensive reflections surrounding it. Based on recently acquired seismic and well data, the geological structure of the Bulla-deniz field along the surface of Horizon VIII and the Upper Kirmaki Sand Suite has been refined. In the northeast, there is a 2 km monoclinal dip along the formation, which later connects with the marine extension of the Cheyrankechmez depression. The structural arch is further complicated in the southeast direction by two parallel longitudinal faults passing through the Kanizdag area.