This study presents the results of microscopic and geochemical analyses of the Menilite Formation from the Polish part of the Outer Carpathians. Twelve Oligocene shales from the Central Carpathian Synclinorium of the Silesian Nappe were examined to evaluate the petrological characterization of the solid bitumen and other organic matter (OM), identify the hydrocarbon evidence in the analyzed samples, and to understand the hydrocarbon generation in low thermal maturity rocks. The OM dispersed in the analyzed Menilite Formation is mainly represented by alginite and bituminite-rich, oil-prone kerogen. The reflectance measurements of vitrinite (VRo %), solid bitumen (BRo %), and the values of the maturity biomarker parameter indicator revealed that the analyzed samples contain immature to early mature organic matter in terms of hydrocarbon generation. Three types of solid bitumen (SB) were noticed: dark brown, almost black in reflected white light with a scratchy or granular surface bitumen (GR), as well as two types of homogenous SB. One reflected shades of brown-orange when observed under UV light, while the other was a non-fluorescent, lighter gray in reflected white light. Solid bitumen appears in samples where the reflectance of vitrinite is equal to at least 0.43 % VRo and has the ability to reflect light from 0.26 to 0.32 % BRo. A strong correlation was found between lighter homogenous solid bitumen reflectance with vitrinite reflectance, CPI 25-31, and dinosterane distribution. The lack of a broad interrelation between geochemical parameters and vitrinite reflectance values was linked with different kerogen mixtures within the analyzed strata. Higher content of bacterial Type II kerogen prompted the generation of early-mature hydrocarbons, while higher input of Type I and/or III kerogen leads to a decrease in the scale of the phenomenon of early-mature hydrocarbons. In Menilite shales, the hydrocarbons are generated in the forms of oil droplets and oil exudates.

Oligocene siliciclastics belonging to the Silesian Unit in the Outer Carpathians were sampled from five locations (Iwonicz Zdrój, Krosno, Równe, Rymanów Zdrój, Zmysłówka) with the first four locations connected to Menilite Shales. The sample from Zmysłówka is an example of the lowermost part of the Krosno Beds. Preliminary geochemical results obtained from the Rock-Eval analysis suggested the presence of immature mixed II/III Type kerogen. Detailed geochemical (GC-MS) and petrological analyses show evidence of extensive phytoplankton blooms, causing the occurrence of episodic ferruginous hypoxic zones. Hypoxic zones were present in the photic zone, where molecular evidence of green and/or brown pigmented sulfur reducing bacteria were marked. The size and character of the blooms were controlled by the palaeoenvironmental conditions. In cases of intense nutrient-rich freshwater loading by a palaeoestuary and/or rainfall, extensive algal blooms were reported. With the increasing aridity and/or decrease of the palaeoestuary impact, the phytoplankton blooms gradually acquired a mostly bacterial character and were reduced in size. The most hypoxic conditions were noted in causes linked with the most intense algal blooms. In most of the cases, algal blooms were dominated by diatoms, suggested by the extensive presence of C25 Highly Branched Isoprenoid, a specific biomarker linked with these organisms. The dinoflagellates only recorded a dominant role in blooms in the Krosno location. A comparison of diterpenoids and triterpenoids revealed that terrestrial organic matter was mostly dominated by gymnosperms like conifers from the Cupressaceae, Pinaceae and Podocarpaceae families. Beside these, the molecular evidence of the angiosperms, bryophytes, and fungi was marked. Both geochemical and petrological analyses confirm the minor role of palaeo-wildfires in the land areas near the deposition place of the analysed samples.

This paper presents a broad overview of laboratory methods for measuring thermal properties and petrophysical parameters of carbonate rocks, and analytical methods for interpreting the obtained data. The investigation was conducted on carbonate rock samples from the Kraków region of Poland in the context of shallow geothermal potential assessment. The measurement techniques used included standard macroscopic examinations; petrophysical investigations (porosity, density); analysis of mineral composition thermal conductivity (TC) and specific heat measurements; and advanced investigations with the use of computed tomography (CT). Various mathematical models, such as layer model, geometric mean, and spherical and non-spherical inclusion models, were applied to calculate thermal conductivity based on mineralogy and porosity. The aim of this paper was to indicate the optimal set of laboratory measurements of carbonate rock samples ensuring sufficient characterization of petrophysical and thermal rock properties. This concerns both the parameters directly characterizing the geothermal potential (thermal conductivity) and other petrophysical parameters, e.g., porosity and mineral composition. Determining the quantitative relationship between these parameters can be of key importance in the case of a shortage of archival thermal conductivity data, which, unlike other petrophysical measurements, are not commonly collected. The results clearly show that the best correlations between calculated and measured TC values exist for the subgroup of samples of porosity higher than 4%. TC evaluation based on porosity and mineral composition correlation models gives satisfactory results compared with direct TC measurements. The methods and results can be used to update the existing 3D parametric models and geothermal potential maps, and for the preliminary assessment of geothermal potential in the surrounding area.

Efficient exploitation of unconventional oil and gas resources requires an extensive knowledge of the natural structures present in the reservoir. Such structures provide information about stress orientation and natural fracture network which are crucial during hydraulic fracturing treatments designing. The X-tended Range Micro Imager (XRMI) tool was used to obtain microresistivity image of wellbore walls which allowed to interpret natural and drilling-induced structures. Most observations concerned natural fractures, small dislocations and calcite/pyrite concretions, also breakouts structures and induced tensile fractures were recorded. Structural analysis of the cores gave an opportunity to examine naturally occurring tectonic structures, including veins and fractures beyond the resolution of XRMI tool. Structure description included genetic type, dip angle, size and mineral filling. Paper presents interpretation of borehole imaging and cores analysis for two wells located in the Baltic Basin, which is a subject of extended unconventional oil and gas exploration. Qualitative and quantitative comparison-of structures observed was carried out. The results obtained from the applied methods showed, that the core analysis enabled recognition of more structures than the XRMI logging.

Paper presents results of 3D modeling and unconventional hydrocarbon resources assessment in the central part of Lublin Basin (south east Poland). Modeling was performed for Lower Paleozoic strata using Petrel software. Input data set comprised well logs, laboratory measurements including RockEval pyrolysis, 2D and 3D seismic survey and their interpretation, results of 1D modeling in BasinMod. Spatial modeling was performed on semi-regional scale. The structural framework of semi -regional model was created based on 51 faults on the area of 7340 km(2). It consist of 120 geological layers and it is divided into 8 zones from the top Cambrian to the top of Silurian. Parametric modeling included such parameters as thickness, bulk density (RHOB), porosity (PHI), water saturation (Sw), vitrinite reflectance (Ro), shale and brittle minerals volumes. For hydrocarbon resources assessment was performed reflectivity model, that allowed establishing zones of hydrocarbon generation, as well as estimation of original content of organic carbon (TOCp), the generation potential expressed as the parameters from RockEval pyrolytic analysis - Hydogen Index (HI) and average generation potential (S1+S2). Preliminary resources assessment for oil, liquid and gas window was performed using equations of modified Schmoker method. Hydrocarbon resources were calculated separately for Caradoc, Llandovery and Wenlock strata in each hydrocarbon generation window. The most productive interval in the area is Wenlock. Resources are presented as GIIP.

The discrete fracture network (DFN) approach is attractive for applications in which the geometry and properties of discrete fractures play a significant role in geomechanics, and resource assessment. (Dershowitz & Doe 1988). Comparison of the simulated data to realistic fractures observed on cores increases confidence in the DFN approach. The aim of this study is prediction of fracture properties for the Lower Paleozoic shale rocks. A DFN model typically combines deterministic and stochastic discrete fractures. The deterministic fractures are those directly imaged through seismic or intersected in wells. Other, usually smaller-scale fractures may not have been detected through seismic, yet may be very important for reservoir performance. These fractures are generated stochastically (Parney et al. 2000). The input data include seismic survey data, well logs with FMI interpretation and was calibrated with measurements and observations on the cores to help ensure accuracy in the estimates of fractures properties. This study was performed using Petrel software from Schlumberger. Typical workflows for modelling of oil and gas reservoirs were applied (e.g. Zakrevsky 2011). The result was 3D fracture distribution model consisted with four zones. In each zone two generations of fractures were created based on well log data. Several seismic attributes were considered as a fracture density drivers for the spatial modeling. Finally the ant tracking structural attribute was chosen as the best indicator of faults and fractures in seismic cube. For the improve the quality of the DFN model, should define the local stress distributions within each tectonic blocks.

Summary The article presents an outline of preliminary static 3D modeling workflows developed by a team of AGH during the last two years of research work. The first stage of the completed work was the integration of variable data types, including the archival and the modern cartographic materials, seismic, well-log and laboratory data from the central and western parts of the Baltic Basin. The models were elaborated at different scales from regional to local. They are designed to be a key part of workflows, which will be used to elaborate the procedures of shale gas resources assesment. According to the authors’ assumptions, they should be matched to geological settings of the Paleozoic Basins of Poland. They also should take into account the main rules of PRMS classification. At the present stage of research obtained preliminary results are not equivocal due to the extremely variable quality of the input data. Also quantity of the modern data seems to be insufficient to obtain statistically significant resources assessment. Elaborated up to now models are base cases. They confirm productivity of the Ordovician-Silurian shale gas system in the Baltic Basin, and can help to establish crucial cut-offs for shale gas accumulations in that area.

Summary The aim of this study is to estimate total gas-in-place volumes for the Lower Paleozoic shale rocks, in part the Baltic Basin of northern part of Poland. For one of the projected horizontal well in Poland, the investigation was carried out. Based on published and literature date the authors built 3D static model which consist structural and parametric data needed for volumetric calculation. The input data include porosity, density, water saturation. The calculations for Polish conditions were compared with production data from North America and China. The analysis were provided for four examples. Based on available data and provided analysis of gas reserves for a single, depending on the fracking results, that the GIIP are changing. The quality and number the input data used to volumetric calculations plays a very big difference on gas resources. Graphics comparison between minimal Canadians and Polish, maximal Chinese (Longmaxi) and USA (Barnett Shale) shows statistical data.

Summary During development of sedimentary basin, pore space of sandstones undergo transformations related to diagenetic stages. These processes include compaction, cementation, dissolution, replacement and recrystalisation, and become more and more advanced with depth. This interactions amends primary porosity, leading to deterioration of reservoir properties. The paper presents diagenetical changes occurred within deeply buried tight Rotliegend sandstones from Polish part of Southern Permian Basin and its impact on reservoir properties

The main objective of the performed modeling was to test methodological solutions. Nevertheless, the obtained results allow to make rough summaries. The analysis of the hydrodynamic character show that the maximum dynamic capacity of the reservoir is determined by the type of injection well. For horizontal well, 700 m length and the same rate like for vertical one, we can inject supercritical CO2 with lower pressure and reach higher total injection volume.

The gas field is located in the southern part of the Fore-Sudetic Monocline, in the western part of Poland, in Rotliegend sandstones, in the Polish part of the Southern Permian Basin. 3D static modelling was performed with the use of the Petrel software from Schlumberger, using typical workflows applied for modelling of oil and gas reservoirs. Ten proportional layers of reservoir zone were set resulting in model composed of over 1 000 000 cells. An average and several alternative models were result of ten stochastic realizations in SGS technique. The quality and number the input data used to develop parametric models plays a very big difference. The most important parameters characterizing the reservoir rocks are: porosity, permeability and vshale. Assessment of potential reservoir and seal rocks based on a quantitative analysis of a number of parameters determining saturated hydrocarbons and their flow in the pore space. Performed of structural- parametric models of the Żuchlów gas field can be successfully used for dynamic simulation and reserves estimation.

The paper presents basic assumptions of tight gas resources. It focuses on a unconventional reservoir rock - Permian Rotliegend sandstones and their properties. Development of sedimentary basin, distribution of reservoir facies, petrophysical parameters of reservoir rock and effectiveness of diagenetic processes determine the possibility of occurrence of unconventional resources. An example of unconventioanl tight gas deposit from Polish part of Southern Permian Basin is discussed with aforementioned guidelines.