Study on the genesis of deposits of the Productive Series of the Bibi-Heybat field by using a complex of borehole data

The majority of developed oil and gas fields in our country are associated with deposits of terrigenous origin. The results of the research carried out provide a basis to conclude that terrigenous reservoirs are not completely homogeneous. Generally, the individual layers differ in their composi’tion in terms of porosity, permeability, shape, size, etc. Therefore, the heterogeneous characteristics of reservoirs should be determined in advance. For this reason, the study of sedimentation conditions of terrigenous layers and the genesis of deposits can be useful for geologists and geophysicists when discovering new fields. This article examines the issue of studying the genesis of deposits of the Productive Series based on the results of quantitative interpretation of borehole data. Sections of wells NoNo X1, X2, X3, X4 from horizons X, XI, XII, XIII, XIV, and XV of the Productive Series (PS) were conditionally chosen as the area of research in the Bibi-Heybat field. The values of effective porosity and volumetric clay content were calculated using established methods and formulas for selected well sections, and histograms of the variation of these values with depth were plotted. The genesis of deposits was studied on the basis of histograms, and facies of stream, bar, and beach-plain origin were identified. The article also defines intervals for the identification of stream, bar, and beach-plain facies in the studied areas and presents 2D and 3D models characterizing the distribution of their thicknesses in the studied region. The research work also involved building 3D models of the distribution of determined facies thicknesses as well as effective porosity, volumetric clay content, and oil and gas saturation across the wells. According to the 3D model analyses, the permeability coefficient value for the study area ranges from 0-120 mD, the porosity value ranges from 0-20%, and the oil and gas saturation ratio value ranges from 0-100%.