The location, geological structure and characteristics of the Kamionki Anticline is presented in terms of possibility of underground CO2 storage. It is situated in the Płock Trough, in the SW part of the Płońsk Block, and represents a synsedimentary graben originated in the Early and Middle Jurassic. It has been explored by a semi-detailed reflection seismic survey and three deep boreholes (Kamionki 1, Kamionki 2 and Kamionki IG-3). Assuming that the anticline is conventionally outlined by a contour line of the top of the Lower Jurassic, its length is about 15 km, width is about 5 km and the area reaches approximately 75 km2. Geological, seismic and reservoir property data allow concluding that this structure is suitable for underground carbon dioxide storage. The primary reservoir level for underground CO2 storage is represented by Barremianmiddle Albian deposits of the Mogilno Formation with an average thickness of 170 metres, containing on the average 85% of sandstones, and showing porosity of about 20% and permeability above 100 mD up to 2000 mD. The sealing series is composed of Upper Cretaceous marls, limestones and chalk reaching the thickness of about 1000 metres. The secondary reservoir level is represented by upper Toarcian deposits of the Borucice Formation.

The paper presents the location, geological structure and characteristics of the Wyszogród and Dzierżanowo anticlines in terms of potential underground storage of carbon dioxide. The Dzierżanowo and Wyszogród anticlines are two of the nine pre-selected structures for underground storage of carbon dioxide in Mesozoic deposits of the Płock Trough. They were detected by seismic profiles and deep boreholes. The Dzierżanowo Anticline is explored in more detail (five boreholes) than the Wyszogród Anticline (one borehole). Lower Cretaceous and Lower Jurassic aquifers have been proposed for CO2 storage in these areas. They have similar parameters: average thickness (144 mand 161 m; 140 mand 112 m, respectively), depth to the aquifer (200-300 m, lower for the Dzierżanowo Anticline), high porosity and permeability of reservoir rocks (several hundred mD and more), high capacity storage of CO2 (much higher for the Wyszogród Anticline) and large thickness of the overburden seal. In both cases, the sealing series require further, detailed investigation of their sealing properties. No faults are observed within the reservoir rocks and overburden seal in the Wyszogród Anticline. They occur in the deeper parts of the Zechstein-Mesozoic succession up to the Lower Cretaceous in the Dzierżanowo Anticline. Due to its degree of exploration and the depth to the aquifer, and similar properties of the reservoir rocks and the sealing caprock, the Dzierżanowo structure seems more favourable for the underground storage of carbon dioxide. The Wyszogród and Dzierżanowo structures may be of interest to several large CO2 emitters in the region: Vettenfall Heat Poland SA - (Siekierki and Żerań, Warsaw) and the Dalkia Łódź ZEC SA, located at a distance of up to 100 kilometres.

The aim of this study was to identify thoroughly the geological structure of the Choszczno Anticline for potential CO2 storage. The paper presents the interpretation of seismic materials for a selected seismic profile reprocessed into a section of reflection coefficients characterized by increased recording resolution as compared to the wave image. Particular attention was paid to the geological complexes associated with the Jurassic reservoir formations suitable for carbon dioxide storage within the anticline. The correlation of the identified layers reflects the lithology and structure of the rock series. It allows determination of the thicknesses of the series and changes within them, and enables linking the individual layers with the lithologic units, based on geological data. The study refers to the whole Zechstein-Mesozoic succession of the Choszczno Anticline, with special emphasis on these series, in which there are potential reservoir formations for CO2 storage. The interpretation has significantly expanded the amount of data provided in standard seismic documentations. While assessing the suitability of the formations for CO2 storage, special attention should be paid to the tectonic disturbances within the Komorowo Formation, especially in the top part of the Choszczno structure. The Reed Sandstone bed is more continuous in this respect. The obtained results seem to suggest wider application of reprocessing of seismic materials into effective reflection coefficients to study the geological structure, also for other structures.

Geological carbon dioxide storing should be carried out with the assumption that there are no leakages from the storage sites. However, regardless of whether the gas which is injected in leaks from the storage site or not, the carbon dioxide stored will influence the environment. In a tight storage site the carbon dioxide injected in will dissolve in the reservoir liquids (groundwater and oil) and react with the rocks of the storage formation. Dissolving CO2 in underground water will result in the change of its pH and chemism. The reactions with the rock matrix of the storage site will not only trigger changes in its mineralogical composition, but also in the petrophysical parameters, because of the precipitation and dissolution of minerals. A leakage of CO2 from its storage site can trigger off changes in the composition of soil air and groundwater, influence the development of plants, and in case of sudden and large leaks it will pose a threat for people and animals. Carbon dioxide can cause deterioration of the quality of drinking waters related to the rise in their mineralization (hardness) and the mobilization of heavymetals' cations. A higher content of this gas in soil leads to a greater acidity and negatively affects plants. A carbon dioxide concentration of ca. 20-30% is a critical value for plants above which they start to die. The influence of high concentrations of carbon dioxide on the human organism depends on the concentration of gas, exposure time and physiological factors. CO2 content in the air of up to 1.5% does not provoke any side effects in people. A concentration of over 3% has a number of negative effects, such as: higher respiratory rate, breathing difficulties, headaches, loss of consciousness. Concentrations higher than 30% lead to death after a few minutes. Underground microorganisms and fungi have a good tolerance to elevated and high concentrations of carbon dioxide. Among animals the best resistance is found in invertebrates, some rodents and birds.