Approximately 80% of water extracted from oil and gas deposits in Poland is disposed of by injection into the rock matrix. The aim of the model research was to predict both the hydrochemical reactions of water injected into wells for its disposal and the hydrogeochemical processes in the reservoir formation. The purpose of hydrogeochemical modeling of the hydrocarbon formation was also to determine the potential of formation waters, injection waters, and their mixtures to precipitate and form mineral sediments, and to determine the corrosion risk to the well. In order to evaluate saturation indices and corrosion ratios, the geochemical programs PHREEQC and DownHole SAT were used. The results of hydrogeochemical modeling indicate the possible occurrence of clogging in the well and the near-well zone caused mainly by the precipitation of iron compounds (iron hydroxide Fe(OH)3 and siderite FeCO3) from the formation water due to the presence of high pressures and temperatures (HPHT). There is also a high certainty of the precipitation of carbonate sediments (calcite CaCO3, strontianite SrCO3, magnesite MgCO3, siderite FeCO3) from the injection water within the whole range of tested pressures and temperatures. The model simulations show that temperature increase has a much greater impact on the potential for precipitation of mineral phases than pressure increase.

The “Sulmierzyce-Odolanów” study area analyzed in the present paper constitutes an example of the presence of deep Zechstein metallic mineralization in the Fore-Sudetic Monocline. Unlike the shallow deposits which are being mined nowadays, these types of areas were not previously considered in terms of their possible extraction. However, in recent years, due to the development of modern mining technologies, this situation has changed and these areas have become prospective for the future documenting of mineral deposits. The threshold parameters delimiting an ore deposit, recommended for use when preparing geological documentation and not compulsory, have been established by the regulation of the Minister of Environment. In the case of stratabound Zechstein deposits they take the equivalent percentage and productivity of only two metals, i.e. copper, as the main useful component, and silver into account. This leads to the underestimation of the resources of ore which also contains other metals, including zinc and lead, which is particularly disadvantageous in the case of deep deposits, which from an economic standpoint, it is advisable to focus on their richest parts and to document, and in the future to extract all the useful metals. Also, the regulation of the Minister of Environment does not take into account the fluctuations of the market prices of metals over time, the impact of which on the equivalent content and productivity of these elements in the deposit is considerable. This paper presents the authors’ own formulas intended to calculate polymetallic equivalent content and productivity taking the share of four elements in the ore into account: copper, silver, zinc and lead. They also enable determining these values for arbitrarily selected time intervals and tracing their changes over time. Apart from the quality parameters it is also possible to calculate the value of mineral resources in the deposit expressed in American dollars per one square meter of its area for each selected time interval. The calculations used the results of chemical analyses of historical drill cores originating from the studied area. A total of 135 historical holes located within its boundaries were analyzed. Based on the obtained figures, the time-varying resources of the polymetallic equivalent (Cu-Ag-Zn-Pb) were estimated along with their market value expressed in American dollars for each year in the time interval of 2012–2016.

In 2011, the Miedzi Copper Corporation (MCC) initiated its exploration program involving deep Cu-Ag deposits in the Fore-Sudetic Monocline. A very vast study area was adopted, along with the use of a wide range of research instruments. In the years 2011–2013 the exploration of MCC involved 21 concession areas. The location of concessions for exploration as well as exploration and prospecting was based on the known prognostic and hypothetical areas with confirmed contact of the Rote Fäule facies with the reduced facies, placed in the proximity of the Zechstein elevations. In 2012 and 2013, historical boreholes drilled mainly by the petroleum industry were logged, and in cases where the preservation of rock material allowed, samples were collected for chemical analyses. Moreover, a wide range of specialized examinations was performed, involving organic chemistry, coal macerals, vitrinite reflectance and petrography, with a particular emphasis on the Rock Eval method. The latter allows the presence of the so-called strong Rote Fäule associated with the presence of the richest mineralized horizons to be established. It was equally important for the purpose of exploration to perform the reprocessing of geophysical data using the innovative method of effective reflection coefficients. This allows transforming a conventional seismic image into an impulse form of seismic records, meaning a temporal sequence of coefficients, whose sections can be correlated with the logs of historical boreholes in order to trace the course of lithological series. This method provides a much higher accuracy for determining structural elements crucial for exploration than before, suggesting the presence of various tectonic phenomena important for mineralization. As a result, a more detailed mineralization distribution model was obtained and the so-called sweet spots were pinpointed, becoming an object of further drilling exploration. The number of active concessions was reduced to 6, which resulted largely not just from the absence of ore, but also from economic premises. The drilling program initiated in 2013 and still continued today allowed the discovery and preliminary documentation of three copper and silver deposits in the Fore-Sudetic Monocline. These are the Mozów and Sulmierzyce deposits, where the presence of prospective areas was previously recorded, as well as the Nowa Sól deposit, discovered in the so-called green field, where no ore exploration was previously conducted. At the current stage of identification, each of these deposits contains resources exceeding 5 million tons of equivalent copper, and the performed economic analyses indicate the viability of their extraction using the modern methods of shaft sinking, air conditioning and waste management.

In the Fore-Sudetic Monocline area, gas deposits occur in carbonate rocks of cyclothems PZ1 (Zechstein limestone Ca1) and PZ2 (main dolomite Ca2). The location of deposits is closely connected with zones of carbonate sedimentation. Generally, gas deposits occur within barrier zones and at the foot of carbonate platforms. The outburst of rock fragments into the heading of the KGHM Rudna mine in 2009 was evidence that gas could also appear in the basin zone Ca1 of the copper deposit. 2D and 3D surface seismic surveys comprise the basic method which is applied to hydrocarbon prospecting. The main advantage of this method is the fact that P-wave velocity and bulk density decrease as a result of gas saturation of the pore spaces. As a result, one can observe anomalous seismic [records(activity?)] which can be connected with gas deposits, and reservoir interpretation of seismic data is based on Direct Hydrocarbon Indicators analysis (DHI). This paper presents and compares seismic images of gas saturation [in traps(trapped?)] in a typical carbonate barrier (Kościan gas field in Ca1) at the foot of a carbonate platform (Lubiatów gas field in Ca2), and in a porous/fractured zone in Ca1 dolomite where there was a gas outburst in the Rudna mine. Based on available well logging data and 1D seismic modeling (synthetic seismograms) this study developed criteria for identification of gas-saturated zones for each case. The results of the study provide the following basic criteria for gas saturation: (1) phase change at Ca1 bottom from negative at the basin zone to positive at the barrier zone - for the Kościan barrier Ca1; (2) the bright spot at the top of the saturated zone - for the Lubiatów deposit at the foot of the carbonate platform; (3) reflections with close to zero amplitude at the bottom of Ca1 dolomites - for the porous and fractured deep-water zone of the Rudna mine.