Prospects of the complexly structured helvetian deposits of the Krukenets basin based on the results of geophysical wells research

Abstract

Increasing hydrocarbon production in Ukraine involves the creation and implementation of new promising methodological and technological means based on modern achievements of science and technology. Analysis of the geological structure of the lithological and stratigraphic strata of the Helvetian stage of the Neogene system of the Krukenets basin of the Bilche-Volitsky zone of the Precarpathian trough confirmed that in each case, there are features both in the structure of the rock matrix and in the conditions of its formation. In this regard, the core samples were studied by the nuclear magnetic resonance method and the main basic criteria for the characteristics of the Helvetian reservoir rock were established. The effectiveness of the gamma-ray spectrometric method and nuclear magnetic resonance was also substantiated. The results of core studies by the nuclear magnetic resonance method allowed us to establish that the longitudinal relaxation time depends on the concentration of certain minerals in the rocks. The available basic material was used to determine the porosity coefficients of rocks using acoustic logging. Experimental studies of the nature influence of the reservoir rock saturation on the acoustic logging readings, as well as the downhole device deviation from the well central direction, were performed. Based on the results of experimental studies of the rock matrix of the Neogene system, it was possible to formulate the main regularities of the individual radioactive elements distribution in the sedimentation basin by gamma-ray spectrometry and, on their basis, to substantiate the directions of using the method in the complex interpretation of typical geophysical studies of complex geological sections of the Neogene system. The presented results of gamma-ray spectrometry allow increasing the efficiency of gamma-ray studies of natural and secondary radiation of complex reservoir rocks, in particular, Neogene sediments of thin-layered lithological and stratigraphic sections.