Charakter przestrzeni porowej cechsztyńskich skał zbiornikowych monokliny przedsudeckiej w świetle badań w elektronowym mikroskopie skaningowym (SEM)
Abstract
SHAPE AND NATURE OF PORE SPACE OF ZECHSTEIN COLLECTOR ROCKS FROM THE FORE-SUDETIC MONOCLINE STUDIED WITH THE USE OF SEM
Summary
The paper presents the results of SEM studies on the nature of pore space on the background of lithology of Zechstein collector rocks. The studies made it possible to introduce six-fold classification of pore space, the criteria of which are given in the Polish text. Furthermore it was found that: (1) The nature of pore space, inherited after the sedimentary environment, was essentially modified under the influence of diagenetic agents. (2) The nature of pore space of the rocks studied is mainly determined by their chemical composition and intensity of diagenetic processes such as leaching, dolomitization, dedolomitization and crystallization of secondary minerals from hydrothermal solutions. (3) The standard techniques of analysis of total and effective porosity appear to be insufficiently ,,sensitive". The results of standard measurements are, therefore, not always usable and especially when they are compared with the data concerning rock microstructure and nature of its pore space. (4) The complex nature of pore space makes it necessary to use especially selected empirical formulae for evaluating conditions of migration of liquid and gaseous hydrocarbons in rock massif. (5) Carbonate rocks with porosity of the order of a few percents are considered as good and economically valuable collectors. (6) Anhydrites often considered as ,,sealing" rocks display pore space of the same type as carbonate rocks with good collector properties.
Summary
The paper presents the results of SEM studies on the nature of pore space on the background of lithology of Zechstein collector rocks. The studies made it possible to introduce six-fold classification of pore space, the criteria of which are given in the Polish text. Furthermore it was found that: (1) The nature of pore space, inherited after the sedimentary environment, was essentially modified under the influence of diagenetic agents. (2) The nature of pore space of the rocks studied is mainly determined by their chemical composition and intensity of diagenetic processes such as leaching, dolomitization, dedolomitization and crystallization of secondary minerals from hydrothermal solutions. (3) The standard techniques of analysis of total and effective porosity appear to be insufficiently ,,sensitive". The results of standard measurements are, therefore, not always usable and especially when they are compared with the data concerning rock microstructure and nature of its pore space. (4) The complex nature of pore space makes it necessary to use especially selected empirical formulae for evaluating conditions of migration of liquid and gaseous hydrocarbons in rock massif. (5) Carbonate rocks with porosity of the order of a few percents are considered as good and economically valuable collectors. (6) Anhydrites often considered as ,,sealing" rocks display pore space of the same type as carbonate rocks with good collector properties.