Lithological and facies models of productive strata of the Lower Kura sag and channels joining the hydrocarbon generation source with deposits

Abstract

Summary Despite the more than 80-year period of oil and gas fields operation in the Lower Kura depression, all the details of their geological structure, fluid and dynamic processes, which took place in the formation of oil and gas deposits here, are still unknown. Therefore, studies that aimed at clarifying the sedimentation models of structures, discovered in the Lower Kura depression, and the processes involved in the formation of multi-layer hydrocarbon deposits confined to them, are urgent. The work is carried out by using an integrated interpretation of geophysical well logging data (GWL) and three-dimensional seismic survey accumulated in the most representative area where the Garabagly field is located. The purpose of the work was to build a volumetric model representing the field like a multidimensional object, contained the geological structure of the area at the most, and made it possible to study the processes of sedimentation and formation of deposits in the Lower Kura depression. The lithological cube is generated by taking into consideration the structural features of the paleo channels, the extension of the distribution of sedimentary bodies, the connectivity of individual layers and their distribution in the vertical and lateral directions. As a result, the nature of the processes specified the spread of channel sediments in the studied area, the role of mud volcanism in the maturation of deposits, and the spatial position of faults supplying multilayer deposits due to the generated fluids at Maikop series, were determined. Generated three-dimensional geological model made possible to conclude the reduction of oil and gas resources in the deposits, to choose the most reasonable scenario for the development of fields in the Lower Kura depression. Based on the obtained results, it was possible to clarify the details of the geological structure of multilayer deposits founded in the Lower Kura depression, and the features of their distribution at three-dimensional space.