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.

Polish brines are highly mineralized and can potentially be used for recovery of selected useful elements such as magnesium and potassium. They also contain a number of other elements, including iodine, bromine, boron, and strontium. The results of the examination of the chemical composition of groundwater from the Mesozoic formations (bromine, iodine, lithium, magnesium, and strontium content) of northern and central Poland were analyzed. The basic statistical parameters of the content of these elements (Br, I, Mg) in brines of the Triassic, Jurassic, and Cretaceous deposits and the content of lithium and strontium in waters of the entire Mesozoic formations were determined. In order to indicate aquifers that are the most suitable for the recovery of bromine, iodine, lithium, magnesium, and strontium, the relationship between concentrations and the depth of retention and dependencies between selected chemical components of these waters were analyzed. It has been found that the mineralization and concentrations of magnesium, bromine, and iodine increase with the age of aquifers, where these waters occur. Triassic waters are the most prospective for bromine and magnesium recovery among all analyzed aquifers. Furthermore, a relationship between the content of bromine, strontium, and magnesium has also been observed. The increase in the content of individual elements observed for lithium, strontium, and bromine with the increasing depth indicates a potential abundance of waters occurring at significant depths. The presented analysis is an approximation of the content of bromine, iodine, lithium, magnesium, and strontium; however, it may be the basis for further studies on the perspectives of using brines from the Mesozoic deposits of central and northern Poland as a source of chemical raw materials.

The results of drill stem tests made on the autochthonous Miocene deposits of the Upper Badenian - Lower Sarmatian age in the Carpathian Foredeep were analyzed. Reservoir tests were performed in open and cased holes, where inflows of formation water of varying saturation degree and sometimes contaminated with drilling mud filtrate, were observed. A total of 58 intervals, geophysically qualified as gas-bearing, were analyzed. Statistical analysis methods were used for determining the influence of the formation depth on the depth of deposition of the Miocene, and also dependence of initial back-pressure exerted on the reservoir during DST, on the depth of deposition of the reservoir. No correlation was found between water flow rate and initial differential pressure. A satisfactory correlation was obtained between hydrostatic pressure of water cushion in the tubing string and reservoir pressure for selected 22 the Miocene intervals in the Dębica region. In this region the pressure quotient php/pz broadly ranged between 0.05 and 0.57. Another correlation was noted between initial back-pressure and a depth at which pressure was measured and initial back-pressure, and formation water flow rate. The regression equations determined with statistical methods can be used for predicting values of formation pressure, initial value of back-pressure, formation water flow rate and initial differential pressure during DST. On this basis technological parameters of successive reservoir tests can be determined for in the analyzed area of the Carpathian Foredeep, particularly in the Dębica region.

Waters with mineralization above 1000 mg/dm3, classified as mineral waters, are exploited in many regions of Poland. Their resources are usually not renewable and their excessive exploitation can lead to the deterioration of their physical and chemical properties and negatively affect their quantitative status.

The stages in the life of a groundwater deposit involve prospecting, exploration, development, and exploitation. Deposit management is the basis for a sustainable and economically successful process of using water resources.

The problem of effective management of mineral water deposit management has not been raised so far, which is why the authors decided to address issues that should be taken into account in the abovementioned process. An integrated approach to the prospecting, exploration, opening, and exploitation of mineral waters combining the knowledge of specialists from various disciplines (hydrogeologists, geologists, drillers and producers) will enable the appropriate management of these resources.

The article describes the basic elements of the process, special attention has been paid to the mineral water deposit development plan conditioning the correct and economically justified exploitation of these waters. This plan should take the development strategy and legal and environmental conditions into account. Hydrogeological and mathematical models of mineral water deposits developed as part of the plan provide the basis for determining the extent of the mining area and estimating water resources. The deposit opening, exploitation, and monitoring methods are important elements of the deposit development plan.

The rational management of underground space, especially when used for various purposes, requires a comprehensive approach to the subject. The possibility of using the same geological structures (aquifers, hydrocarbon reservoirs, and salt caverns) for the storage of CH4, H2 and CO2 may result in conflicts of interest, especially in Poland. These conflicts are related to the use of the rock mass, spatial planning, nature protection, and social acceptance.
The experience in the field of natural gas storage can be transferred to other gases. The geological and reservoir conditions are crucial when selecting geological structures for gas storage, as storage safety and the absence of undesirable geochemical and microbiological interactions with reservoir fluids and the rock matrix are essential. Economic aspects, which are associated with the storage efficiency, should also be taken into account.
The lack of regulations setting priorities of rock mass development may result in the use of the same geological structures for the storage of various gases. The introduction of appropriate provisions to the legal regulations concerning spatial development will facilitate the process of granting licenses for underground gas storage. The provisions on area based nature protection should take other methods of developing the rock mass than the exploitation of deposits into account. Failure to do so may hinder the establishment of underground storage facilities in protected areas. Knowledge of the technology and ensuring the safety of underground gas storage should translate into growing social acceptance for CO2 and H2storage.

Oil can be produced from reservoirs by use of primary methods that use natural reservoir drive, secondary methods, involving a physical displacement of oil and tertiary (enhanced), in which additional types of energy support oil recovery. About 25-35% of original oil in place for light and medium oil and about 10% heavy oil could be extracted by primary and secondary methods. Injection of CO2 into the oil fields (CO2-EOR) is one of the tertiary oil recovery method. Carbon dioxide is used for increasing oil extraction due to the fact that: to maintain reservoir pressure, reduces the oil viscosity and facilitates its movement in the reservoir, reduces density and increase the volume of oil, interacts with rocks. Depending on the oil composition and the reservoir pressure and temperature injected carbon dioxide can displace oil from the reservoir miscible or immiscible. Additional 10-20% of the oil extraction over primary and secondary methods recovery can be obtained under the miscibility conditions, in immiscibility condition additional oil production is lower. EOR method selection depends on many geological, reservoir and economic parameters. These include: density, viscosity and composition of the oil, minimum miscibility pressure, the recovery factor and vertical and horizontal reservoir variability. Using the above criteria appropriate EOR method for given oil field can be selected. The five parameters: the reservoir depth, the oil density, pressure and temperature of the reservoir is used for the selection of oil fields suitable for miscible oil displacement.