Sequestration, i e. trapping and storage of CO2 is one of the methods of reduction of emission of this gas to atmosphere, as it is treated as one of the main factors responsible for the greenhouse effect. Methods of CO2 sequestration may be divided into chemical, biological and physical processes. The last category is related to the intensification of hydrocarbons mining - being oil and natural gas, as well as the storage in the oceans and deep geological structures (underground reservoirs after mining of hydrocarbons, saline water bearing levels). A basic condition determining the possibility of underground CO2 storage is occurrence of thick deposit rocks of significant reach and good collecting properties (porous and permeating) which are covered with insulating rock overlay. Carbon dioxide that is pumped into the deep geological structures, mainly to water-bearing levels, will initiate chemical processes in the following systems: CO2 - saline water, CO2 - rock, saline water (permeated with CO2) - rock. One of the effects of occurrence of chemical processes at the place of CO2 pumping may be increase or limitation of values of rock storage properties, and more importantly, their porosity and permeability.