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In the Polish part of the Carpathian Foredeep, an intensification of gas exploration and exploitation from Miocene strata took place in the middle of the twentieth century. In spite of a good degree of geological and reservoir recognition, the area of the Carpathian Foredeep is still considered to be prospective for the discovery of new gas reservoirs. Here we analyse statistically selected reservoir parameters of Miocene deposits, such as total porosity, effective permeability and reservoir water inflow. These parameters have been determined on the basis of interpretations of results of well logs and reservoir tests with tubular bed samplers (DST, Drill Stem Test). Analytical results in the form of regression and dependence of the logarithm of permeability as a function of porosity show a weak correlation. However, in the study area, the distribution of porosity values for Miocene strata is close to normal.

A mini review of the topic of deformation bands is presented in the paper. The concept of deformation bands is defined and their impact on the flow of fluids in porous sedimentary rocks is determined. Deformation bands are mm-thick low-displacement deformation zones which have intensified cohesion and lower permeability compared with ordinary fractures. This term was introduced in 1968 in material science, ten years later it appeared in the geological context. This microstructures can occur as barriers or migration pathways for hydrocarbons. Their role depends mainly on microstructural features, and they are also considered in reservoir modeling. The occurrence of deformation bands in Poland is also outlined and discussed - they have been described in Western Outer Carpathians (Magura and Silesia nappes). [ABSTRACT FROM AUTHOR]