oa Evaluation of the Void Space Structure and Reservoir Properties of Rocks in the Visevian and Turnaisian Formations of the Berezivske Field of the Dnipro-Donetsk Depression

Estimating the void space structure of reservoir rocks from well logs plays a significant role in the exploration and development of complex resources, but faces challenges. What’s more, the methodology for studying the void space structure of complex reservoir rocks is paid little attention at present. In this paper, the typical visevian and turnaisian formations in the interval of 5800–6110 m in a well 203 of the Berezivske field of the Dnipro-Donetsk depression are used as an example. The data on compressional and shear wave velocities, as well as density, were utilized for a quantitative assessment of the void space structure. Based on the analysis of input data, the authors have established the most optimal initial approximations for the void formats of the investigated intervals as follows: intergranular voids – 0.699; transitional voids – 0.060 - 0.084; microcracks – 0.0028 – 0.0031; caverns – 4. Inversion of acoustic data for the characterization of the void structure was conducted using special software. Concentrations of void formats were identified. The calculated data revealed the contributions of different types of porosity to the total porosity of rock. It has been established that granular-cavernous porosity and fractured-cavernous-granular porosity are prevail for the visean and tournaisian deposits in a well 203 of the Berezivske field.