• Energy Research

This paper presents the results of a research project aimed at evaluating the unconventional natural gas potential of the autochthonous Miocene sediments in the Polish part of the Carpathian Foredeep. The primary objective of the study was to re-evaluate the biogenic gas generation system within Miocene sediments, paying special attention to unconventional gas resources accumulated in tight mudstone formations. The four-dimensional (4D) petroleum system modeling method (PetroMod software) was used to reconstruct the basin geometry and three-dimensional (3D) evolution through a geological timescale, in particular the progress of gas generation, migration, and accumulation processes, as well as their consequences for gas exploration and development. Special attention was paid to the dynamics of gas generation processes and the advancement of sediment compaction and their time dependence, as well as to the progress and outcomes of gas migration and accumulation processes. The results indicate significant potential for unconventional gas accumulations in mudstone reservoirs. However, part of the biogenic gas resources occurs in a dispersed form. Analysis of the dynamics of biogenic gas generation and accumulation conducted on a basin scale and within particular sedimentary complexes and depth intervals allowed an indication of the premises regarding the most favorable zones for mudstone–claystone reservoir exploration.

New seismic data and the completion of the K-1 petroleum exploratory well, located close to the axial zone of the Mogilno-Łódź Trough (Polish Lowlands) delivered new insight into local structural, tectonic, facial and thermal variability of this geological unit. In this paper, the two variants of 3D models (SMV1 and SMV2) of Permian-Mesozoic strata are presented for the salt pillow related Kłecko Anticline, while resources assessment was confined to the Rotliegend Enhanced Geothermal System (EGS) type reservoir, that is divided into Playa, Eolian and Fluvial facies-based complexes. Using very conservative assumptions on the methods of the EGS reservoir development, authors assessed that heat in place and technical potential for eolian sandstones are about 386 PJ and ca. 2814 kW, respectively, and for Fluvial 367 PJ and ca. 2850 kW in relation to the volume of 1 km3 at depths of about 5000 m b.s.l. The authors recommend for the further development of the Eolian complex because of its low shale content, influencing the high susceptibility to fracking. The presented research is the first Polish local resources assessment for an EGS reservoir in sedimentary Rotliegend, within thermal anomaly below the salt pillow, which is one of over 100 salt structures mapped in Poland.

Model simulation allows to present the time-varying temperature distribution of the ground source for heat pumps. A system of 25 double U-shape borehole heat exchangers (BHEs) in long-term operation and three scenarios were created. In these scenarios, the difference between balanced and non-balanced energy load was considered as well as the influence of the hydrogeological factors on the temperature of the ground source. The aim of the study was to compare different thermal regimes of BHEs operation and examine the influence of small-scale and short-time thermal energy storage on ground source thermal balance. To present the performance of the system according to geological and hydrogeological factors, a Feflow® software (MIKE Powered by DHI Software) was used. The temperature for the scenarios was visualized after 10 and 30 years of the system’s operation. In this paper, a case is presented in which waste thermal energy from space cooling applications during summer months was used to upgrade thermal performance of the ground (geothermal) source of a heat pump. The study shows differences in the temperature in the ground around different Borehole Heat Exchangers. The cold plume from the not-balanced energy scenario is the most developed and might influence the future installations in the vicinity. Moreover, seasonal storage can partially overcome the negative influence of the travel of a cold plume. The most exposed to freezing were BHEs located in the core of the cold plumes. Moreover, the influence of the groundwater flow on the thermal recovery of the several BHEs is visible. The proper energy load of the geothermal source heat pump installation is crucial and it can benefit from small-scale storage. After 30 years of operation, the minimum average temperature at 50 m depth in the system with waste heat from space cooling was 2.1 °C higher than in the system without storage and 1.6 °C higher than in the layered model in which storage was not applied.

Rising fuel prices, changes in energy markets, and concern for the environment make it necessary to develop new solutions and technologies. The development of new technologies brings with it the need to take risks associated with unpredictable consequences, technological immaturity, and other issues. However, without these elements, technological development is not possible. In this study, installations related to two different technologies—Enhanced Geothermal System (EGS) and Carbon Capture, Utilization, and Storage (CCUS)—are reviewed. An Enhanced Geothermal System is a technology for exploiting the energy stored in hot dry rocks. Carbon Capture, Utilization, and Storage is an important technology for reducing CO2 emissions. The combination of these two technologies in CO2–EGS systems can bring significant environmental benefits. This paper reviews the most important CCUS and EGS systems in the world to form a baseline for similar, future technology investment in Poland.

The Zechstein petroleum system in the Polish part of the SPB stands out for the following characteristics: (i) source rocks reveal poor to fair oil-source potential, but ocally it is very good to excellent, (ii) the best reservoir rocks were on slopes and carbonate platforms, (iii) reconstruction of petroleum processes showed that the initiated of generation and expulsion took place in early Triassic and finished in the late Jurassic time, (iv) migration and accumulation of hydrocarbons was held in the same time as processes of generation and expulsion, (v) critical moment for this petroleum system which is connected with the main phase of generation and migration is dated for the beginning of the middle Triassic, (vi) on the part of area the critical point is located in the beginning of Neogene (after Laramian inversion).