Favorable Areas Research Articles

Applications of high-resolution seismic frequency and phase attribute analysis techniques

Seismic prospecting for oil and gas exploration and development is limited by seismic data resolution. Improving the accuracy of quantitative interpretation of seismic data in thin layers, thereby identifying effective reservoirs and delineating favorable areas, can be a key factor for successful exploration and development. Historically, the limit of seismic resolution is usually assumed to be about 1/4 wavelength of the dominant frequency of the data in the formation of interest. Constrained seismic reflectivity inversion can resolve thinner layers than this assumed limit. This leads to a series of highresolution quantitative interpretation methods and techniques have been developed. Case studies in carbonates, clastic, and unconventional reservoirs indicate that the application of quantitative interpretation techniques such as high-resolution seismic frequency and phase attribute analysis can resolve and allow/or allow quantitative estimation of rock and fluid properties in such seismically thin layers. Band recovery using high resolution seismic processing technology can greatly improve the ability to recognize geological details such as thin layers, faults, and karst caves. Multiscale fault detection technology can effectively detect small-scale faults in addition to more readily recognized large-scale faults. Based on traditional seismic amplitude information, high-resolution spectral decomposition and phase decomposition technology expands seismic attribute analysis to the frequency and phase dimensions, boosting the interpretable geological information content of the seismic data including subsurface geological characteristics and hydrocarbon potential and thereby improving the reliability of seismic interpretation. These technologies, based on high-resolution quantitative interpretation techniques, make the identification of effective reservoirs more efficient and accurate.

A Novel Method to Achieve Preferable Bone-to-Implant Contact Area of Zygomatic Implants in Rehabilitation of Severely Atrophied Maxilla.

Purpose: To propose and evaluate a novel method for achieving a favorable bone-to-implant contact (BIC) area for zygomatic implants (ZIs). Materials and Methods: Patients who needed ZIs to restore a severely atrophied maxilla were recruited. In preoperative virtual planning, an algorithm was utilized to find the ZI trajectory that would achieve the largest BIC area with a predefined entry point on the alveolar ridge. The surgery was conducted according to the preoperative plan with the assistance of real-time navigation. Area BIC (A-BIC), linear BIC (L-BIC), distance from implant to infraorbital margin (DIO), distance from implant to infratemporal fossa (DIT), implant exit section, and deviation of the real-time navigated surgery were measured and compared between the preoperative plan and the placed ZIs. The patients were followed up for 6 months. Results: Overall, 11 patients with 21 ZIs were included. The A-BICs and L-BICs were significantly higher in the preoperative plan than in the placed implants (P < .05). Meanwhile, there were no significant differences in DIO or DIT. The planned-placed deviation was 2.31 ± 1.26 mm for the entry, 3.41 ± 1.77 mm for the exit, and 3.06 ± 1.68 degrees for the angle. All ZIs survived to the 6-month follow-up. Conclusion: This novel method can virtually calculate the trajectory of ZIs and transfer the preoperative plan to surgery to acquire a favorable BIC area. The actual positions of placed ZIs were slightly deviated from the ideal due to navigation errors.

Fine structure interpretation and reservoir forming characteristics analysis of Jurassic Badaowan Formation in Madong area of Xiayan fault zone

Fine structural interpretation is one of the effective methods to find favorable structural traps and targets. Aiming at the fault interpretation of Jurassic Badaowan Fm in Madong area of Xiayan fault zone is not fine and structural characteristics are not implemented, the structural characteristics of Jurassic Badaowan Fm are implemented and favorable traps are found through the study of seismic, well logging and geological comprehensive methods. The results show that the structure of Jurassic Badaowan Fm in Madong area is high in the north and low in the south. The first member of Badaowan Fm is a delta front subaqueous distributary channel deposit, which is a hydrocarbon enrichment zone. Oil and gas are adjusted along the relay of deep and shallow faults, and the great fault zone and the inherited uplifting zone are favorable accumulation areas of Jurassic Badaowan Fm in Madong area. In this paper, the relationship between deep and shallow fault system and hydrocarbon distribution of Badaowan Fm in Madong area is systematically reviewed for the first time. Combined with the palaeohigh distribution, three favorable hydrocarbon accumulation zones are identified, which provides favorable targets for exploring the hydrocarbon accumulation potential of Badaowan Fm.

Application of Forward Modeling in Putaohua Oilfield

Putaohua Oilfield is bounded by the large fault on the south side of Pu A1 Well. It is divided into Pubei and Punan development zones on the plane. It is an oilfield that has been developed by water injection for more than 30 years. With the increase of development time, the water content of oil wells increases rapidly, and the oil production of the oilfield decreases rapidly,In order to realize the study of petroleum geological potential in this area, find out the favorable target area for well layout, and effectively improve the drilling success rate,first of all, we need to do forward modeling for the study area to lay a solid foundation for subsequent research. This paper analyzes the change characteristics of seismic wave frequency attenuation attribute in reservoir oil and gas, and applies it to the study of reservoir oil and gas prediction in Putaohua Oilfield.

Study on tight reservoir law and prediction of favorable areas - Take Wangjiawan well block Wang 107 as an example

When the development of oil field continues, the production efficiency of the whole oil well will decline significantly. It is of importance to analyze the geological factors related to the reservoir storage law in order to re recognize the current status of the oil well and extract more resources from the oil well. This paper expounds that at the stage of oilfield development, the research on reservoir characteristics, reservoir sedimentary facies and reservoir characteristics and laws are discussed in depth and comprehensively, and the prediction of favorable areas of the oilfield is studied, which has brought corresponding references to oilfield staff. For the late stage of oilfield development, we should carry out fine geological research, determine the geological type, provide the best data base for improving the development plan of the reservoir, and carry out scientific analysis and research to improve the productivity of the late stage of reservoir development, so as to achieve the expected production efficiency.

Reservoir Characteristics and Favorable Area Prediction of Chang-6 Reservoir in Zhouguan Area, Ordos Basin

Reservoir Characteristics and Favorable Area Prediction of Chang-6 Reservoir in Zhouguan Area, Ordos Basin

Contribution of Climate Scenarios RCP4.5 and RCP8.5 to the Study of Climate Change Impacts on Cocoa Farming in C&amp;#244;te d’Ivoire

In the particular context of climate change in Côte d’Ivoire and the vulnerability of farmers to its effects, one of the major issues is how these changes could impact cocoa yields of cocoa production areas. Thus, the objective of this study is to sustainably increase the resilience of all cocoa farming stakeholders to the impacts of climate change. The study was carried out in the central and southern areas of Côte d’Ivoire with a focus on eleven localities that have many communities of cocoa producers and a humid climate. The rainfall and temperature observation data using come from the CRU, they cover the historical period from 1971 to 2000 at 0.5o × 0.5o horizontal scale. As for the RCP4.5 and RCP8.5 climate scenarios, they come from the CORDEX database and cover the 2021-2050 period. The methodology is based on the calculation of climatic indices sensitive to cocoa cultivation which are the number of consecutive dry days (CDD), the number of consecutive wet days (CWD), the amount of rain during the rainy season and the maximum temperature above 33℃. The results show that for all the localities studied, indices such as CDD and CWD could experience an increase. In addition, the total amount of rain during the long rainy season (April to June) is calculated on the basis of the threshold of 700 mm representing the minimum annual precipitation during the rainy season necessary for good growth of the cocoa tree. It reveals that for the two scenarios the cumulative rainfall will all be greater than 700 mm. Regarding temperatures, the central and southern areas could have a low number of hot days (temperature greater than or equal to 33℃ which is the tolerable threshold for cocoa cultivation). The eleven localities, therefore, remain favorable areas for cocoa cultivation in terms of climatic conditions based on temperature and rainfall, despite the regional dimension of the effects of climate change and the associated constraints.

Cold wintering of coastal birds in the source and upper reaches of the Angara river: Changes in abundance and species structure in the conditions of a sharp climate warming

Based on long-term research (1972-2023) and analysis of literature data, materials on the dynamics of the number and species structure of wintering shorebirds and waterfowl on cold wintering in the source and upper reaches of the Angara River (up to the town of Usolye-Sibirskoye) are presented. This is the largest cold wintering of coastal birds in Eastern Siberia – up to 55.0-60.0 thousand birds, the formation of which is due to very specific conditions of the upper reaches of the Angara River. This is the thermal refugium of the Upper Angara region, which ensures the accumulation of birds at the end of migration in more favorable areas of this region. It is divided into two sections: the first stretches from the source of the Angara River to the village of Taltsy, the second from the Irkutsk hydroelectric dam to the town of Usolye-Sibirskoye, and in warm winters slightly below it. On the basis of special works on the study of the dynamics of the number and species structure of birds, special methods have been developed: accounting on ice holes, accounting during the evening flight of birds to the lake Baikal (during cold periods) and accounting using a hovercraft (SVP) (during periods of severe climate warming). The basis of wintering birds is the Goldeneye Bucephala clangula (from 95.0% to 98.5% of their total species structure). However, the structure of secondary species can increase dramatically and we have noted new species that have never been found here before. The collected materials allow us to understand the reasons that determine the dynamics of the number and species structure of coastal birds in the “cold” wintering grounds of Inner Asia in the conditions of a sharp warming of the climate

Leptospirosis outbreak in Tanzania amidst COVID-19 pandemic: current challenges and future recommendations.

Leptospirosis outbreak in Tanzania amidst COVID-19 pandemic: current challenges and future recommendations.

The Kura-Araxes ‘expansion’: A climate change-related phenomenon?

Two of the documented global climate changes of the Holocene that are known in the academic literature as the ‘5.2 ka BP’ and ‘4.2 ka BP’ events, coincide with two important stages of the Early Bronze Age Kura-Araxes culture of Armenia. The ‘4.2 ka BP event’ coincides with the final stage of this culture, the process of fragmentation and decline observed for the Kura-Araxes from 2500 BC onwards. It ends at around 2200 BC with abandonment or destruction of the Kura-Araxes settlements, accompanied by increased population shifts that led to almost total desertion of large areas both in the Kura-Araxes interfluve, the ‘homeland’ of this culture, and elsewhere. In parallel, this process was accompanied by migrations of new population groups (the influx of the bearers of the ‘Kurgan culture’ into the highland). The second phenomenon is the so-called ‘Kura-Araxes expansion’ which took place some hundred years prior. The dating of the ‘expansion’ at around 3000-2900 BC shows that it took place in another period of drastic climate change. The manifestations of the societal crisis observed in the Kura-Araxes cultural world, the increased mobility of the population and the movements (‘expansion’) to more favourable areas may indicate that we are dealing with interrelated phenomena.

Globally Published Literature on Library and Information Science Professionals: A Bibliometric Review ( 1970-2021) Authors

The study targets examining the exploration yield on the key terms of librarianship within 52 years (1970-2021). The investigation cover essentially the quantity of articles, language of articles, top research oriented organizations and countries, topmost publication source, highly productive authors, highly interested research area, commonly used keyword and so forth. A complete bibliometric study was directed utilizing the Science Citation Index data set, Web of Science (Core Collection). This research fills in as an asset for future research activities by revealing insight into librarianship. In particular, the outcomes uncover that the mostly chosen publication category is article and the research referred to articles are from United States and the top productive organization is also from USA. The preferred language is English for publications and the most favored research area is the “Information Science Library Science” during this time span. This bibliometric research is significant for all those researchers who relates to librarianship and who need to see the publication trends in this profession.

Rapid electron transfer-promoted tetracycline hydrochloride degradation: Enhanced activity in visible light-coupled peroxymonosulfate with PdO/g-C3N4/kaolinite catalyst

In this work, a novel highly dispersed PdO/g-C3N4/kaolinite (P/CNK) composite was synthesized to activate peroxymonosulfate (PMS) under visible light for tetracycline hydrochloride (TCH) degradation. The 4 %P/CNK catalyst showed the best catalytic ability for TCH degradation within 20 min (94.5 %) over the vis/PMS system. The favorable specific surface area and pore volume of CNK allowed for the high dispersion of PdO and the adsorption of PMS, while PdO anchoring on CNK endowed the catalyst with channels and acceptors that could accommodate a large number of electrons to achieve rapid transfer between electrons. Furthermore, kaolinite is inexpensive, and the plentiful hydroxyl groups on the kaolinite surface can accelerate the self-decomposition of PMS. The 4 %P/CNK system also showed excellent degradation efficiency under different pH conditions and maintained its catalytic activity (87.1 %) after five cycles. The intermediates produced during the degradation of TCH and the corresponding differences in aquatic toxicity were identified. The results of electron paramagnetic resonance and reactive oxygen species quenching experiments showed that 1O2 was the key reaction species, while O2− and h+ were secondary species during the degradation process. In addition to TCH, 4 %P/CNK also had good degradation and mineralization effects on sulfamethoxazole, chlortetracycline, and carbamazepine. This work provides a deep foresight into the efficient degradation of antibiotic pollutants by kaolinite-based catalytic materials in a photocatalytic coupled PMS system.

Organic Geochemistry and Hydrocarbon Generation Characteristics of Shale of the Fourth Member of Yingcheng Formation in the South Shuangcheng Fault Depression, Songliao Basin

In order to evaluate the potential for oil and gas resources in the deep fault depression of the Northern Songliao Basin, shale from the fourth member of the Yingcheng Formation (K1yc4) in the South Shuangcheng Fault Depression was selected as an example. The organic geochemical characteristics such as abundance, type and maturity from experiments on low-maturity source rock samples, the hydrocarbon generation conversion rate, hydrocarbon generation amount and hydrocarbon generation period of the shale from K1yc4 were evaluated via the chemical kinetics method. The hydrocarbon generation threshold of shale from K1yc4 in the South Shuangcheng Fault Depression was analyzed by examining the organic matter (OM) in shale core samples from K1yc4. Based on the thermal simulations to an approximate buried depth of 750 m, the maximum oil-generation stage corresponds to an approximate buried depth of 1380 m. The amounts of generated oil and gas from the shale in K1yc4 are approximately 2.417 × 108 t and 0.546 × 1011 m3, respectively. The shale in K1yc4 generated crude oil mainly during the sedimentary period of the Qingshankou Formation, Yaojia Formation and Nenjiang Formation, and mainly generated natural gas during the sedimentary period of the Nenjiang Formation. In the South Shuangcheng Fault Depression, the high parts of the local structure are the favorable areas for oil and gas exploration of K1yc4 in the sag zone, which could be used for the combined production of shale oil, tight sandstone oil and conventional oil.

A novel Mahalanobis distance method for predicting oil and gas resource spatial distribution

Accurate prediction of spatial distribution of petroleum resources is important for petroleum exploration. Mahalanobis distance is a popular and effective method to predict the spatial distribution of oil and gas. However, this method has equal weights for each variable, exaggerates secondary variables, and is prone to misjudge when the distance is close or equal, which impairs the accuracy of classification. To solve these problems, this paper proposes a novel Mahalanobis distance method based on genetic algorithm (GA-MD) to optimize attribute weights. The Sangonghe Formation in the hinterland of the Junggar Basin was used as an example, the validity of GA-MD was evaluated in the exploratory well data set. Compared with the current mainstream methods, the results show that the accuracy of GA-MD method is the highest, and the accuracy is improved by 2–6.2%. The application effect of the proposed method is verified by the prediction result of oil and gas probability map, the GA-MD method not only shows higher oil and gas bearing probability in the reserve areas but also has better trend extrapolation ability compared with other methods. Based on the GA-MD results, the favorable zones with remaining petroleum resources in the Sangonghe Formation in the hinterland of the Junggar Basin were visualized. Three types of favorable oil and gas distribution areas are selected. The favorable areas provide a basis for quantitative decision-making for the optimization of the next drilling strategy and determination of oil and gas exploration deployment direction in the study area.

Variations of Pore Structure and Methane Adsorption of Continental Deformed Shales from Small-Scale Anticline and Syncline: Two Cases Study of the Triassic Yanchang Formation, Ordos Basin and Jurassic Yaojie Formation, Minhe Basin.

In order to investigate the effect of tectonic compression on pore structures and methane adsorption capacity, the continental deformed shales are collected from the Rujigou section in the Ordos Basin and the Hongshawan section in the Minhe Basin as research objects. The porosity, N2 and CO2 adsorption, field emission scanning electron microscopy (FE-SEM), and methane isothermal adsorption experiments are used to investigate the pore structure and methane adsorption of continuous deformation shales. Combined with formation curvature, the quantitative correlations between tectonic compression deformation and reservoir structure parameters and methane adsorption are analyzed. The interlayer pore, intergranular pore, dissolution pore, and microfracture are developed, and the amounts of microfractures are obviously higher in anticlinal cores than that of the anticlinal wings. The porosities for the Rujigou and Hongshawan sections are 2.1-4.73% (avg 3.21%) and 1.49-9.05% (avg 4.80%), respectively. The corresponding mesopore volume, specific surface area, and average diameter for the Rujigou section are 0.022-0.038 cm3/g, 12.35-14.30 m2/g, and 8.76-11.21 nm and for the Hongshawan section are 0.0033-0.0052 cm3/g, 0.376-0.875 m2/g and 21.61-36.37 nm, respectively. The corresponding micropore specific surface area and pore volume for the Rujigou section are 11.301-16.068 m2/g and 0.0033-0.0051 cm3/g and for the Hongshawan section are 10.951-15.912 m2/g and 0.0043-0.0058 cm3/g, respectively. The methane adsorption capacities for the Rujigou and Hongshawan sections are 2.76-3.82 mg/g and 1.62-2.135 mg/g, respectively. The porosity, mesopore and micropore structure parameters, and methane adsorption capacity in synclinal core are lower than those in synclinal wings. However, the above tendency is reversed for the anticline, whose adsorption capacity in the anticlinal core is higher than that in anticlinal wings. There exist high correlations between formation curvature and pore structure, physical property, and methane adsorption, indicating that formation curvature has a significant effect on the shale reservoir. By combining theoretical maximum adsorbed gas and free gas results, it implies that the anticlinal core undergoing moderate structural compression deformation can provide more methane adsorption sites and reservoir space, which is the shale gas favorable accumulation area. This study could provide beneficial references for continental shale gas exploration and evaluation in complex structure areas.

Restoration of palaeogeomorphology and its petroleum-geological significance: Transitional-facies deposition during the early Permian in the southeastern Ordos Basin, North China

The identification of favourable shale-gas areas in marine-continental transitional shales are challenging because of the multiple thin producing layers and abrupt lateral pinch-outs. Using data obtained from drilling, logging, and 3D seismic and natural gamma spectroscopic logging, this paper investigates the control of early Permian palaeogeomorphology on the distribution of organic-rich shale in the southeastern Ordos Basin. Using the impression method and de-compaction correction of strata thickness based on seismic velocity reconstruction, we restore the karst palaeogeomorphology at the top of the Taiyuan Formation for the early Permian. Three geomorphic units including karst highland, karst slope, and karst depression are identified, and constitute a geomorphological pattern of interjacent depressions and highlands. In addition, based on the multi-lithological eigenvalue method, the spatial distribution of transitional shales in the Shan 2 lower sub-member of the lower Permian Shanxi Formation was inferred using post-stack seismic parameter inversion. Our results show that organic-rich shale is distributed mainly in the low section of Shan 2 lower sub-member, which is controlled by karst palaeogeomorphology mainly distributed in karst depressions. Organic-rich shale distributed in karst depressions are characterised by large cumulative thickness, high TOC, moderate thermal maturity, strong hydrocarbon generation intensity, and relatively high gas content, indicating that shale-gas sweet spots should be distributed mainly in karst depressions rather than in highlands or slope areas. Meanwhile, Th/U and Th/K ratios, which indicate paleo-environment during the period of shale deposition, show that the strength of reducing conditions was greatest in karst depressions, moderate in karst slopes, and lowest in karst highlands. Therefore, it is inferred that the distribution of shale-gas sweet spots may be related to the weakly reducing environment, which favoured the preservation of organic-rich sediments during sedimentation. The upper section of Shan 2 lower sub-member was dominated by a high-energy transitional sedimentary environment, and the paleo-redox conditions tended to be oxic, disfavouring the preservation of shale organic matter, and the organic-rich shale in the upper section is relatively poorly developed. This study shows that palaeogeomorphology and paleo-redox conditions affect the deposition and preservation of organic-rich sediments in lower section, the relationship between palaeogeomorphology and the distribution of organic-rich shale can provide reference for shale gas sweet spots prediction and promote the rapid exploitation of shale gas in eastern Ordos Basin.

Karst paleotopography on top of the Dengying Formation and petroleum geological significance in the Central Sichuan Basin, China

Reconstructing karst palaeogeomorphology is a useful approach to identifying target areas for oil and gas exploration. This study used the elevation method to reconstruct the karst palaeogeomorphology at the top of the 4th member (Z2dn4) of the Dengying Formation (Z2dn) in the Central Sichuan Basin based on 2D and 3D seismic and drilling data. The bottom of the Longwangmiao Formation and the top of the 2nd member (Z2dn2) of the Z2dn were optimized as the upper and lower base levels, respectively. The reconstructed palaeogeomorphology was divided into five types – slopes, erosional peneplains, monadnocks, domes and depressions – according to their morphology, scope and gradient, allowing inference of the palaeohydrological conditions. Slopes were subdivided into gentle (&lt;1.2°) and steep (≥ 1.2°; maximum gradient around 16°). Reservoirs on steep slopes and monadnocks are the most developed, owing to their considerable hydraulic head differences, strong palaeohydrodynamics, and intense erosion and incision. Steep slopes with more developed karst porosities are banded and immediately adjoin a regional hydrocarbon generation centre. Hydrocarbons generated in this centre tend to migrate laterally and become entrapped in porous slopes and their vicinities. Consequently, hydrocarbons move upward along steep slopes and, preferentially, slopes and monadnocks. Thus, the steep slope zone and its vicinity (including some monadnocks, gentle slopes and peneplains) are the most favourable areas for exploration of hydrocarbon reservoirs and should be the primary targets.

Features of Seasonal Growth of Shoots of the Crimean Population &lt;i&gt;Juniperus deltoides&lt;/i&gt; R.P. Adams

Juniperus deltoides is one of the most common junipers in the Crimea. The species is included in the Red Book of the Republic of Crimea. One of the leading reasons for the decline in the population is the low level of its natural renewal. Among the leading factors affecting the growth and development of individuals, a number of abiotic factors can be distinguished. On this basis, the purpose of the study was to assess the characteristics of the seasonal growth of J. deltoides shoots in connection with the weather and edaphic-orographic conditions of the Crimean Mountains. Research objectives: to identify the main abiotic factors affecting the growth of J. deltoides shoots; establish the strength of the influence of these factors. Using the methods generally accepted in forestry and geobotany, we carried out the laying of trial plots with the selection of model trees. The length of the shoots was measured according to the generally accepted method for the current year and for the two previous ones. To determine the types of habitat conditions, we used the method of P.S. Pogrebnyak. As a result of the research, it was found that the greatest influence on the growth of shoots of J. deltoides in the Crimean mountains has the amount of precipitation in the period from February to June. The maximum increase was observed in individuals of the western group and amounted to 5.80 0.34 cm in 2021. The growth height of individuals above sea level has a lesser effect on the strength of shoot growth. The influence of this factor is 52.9%. The exposure of the slope and the edaphic conditions of the habitats have almost the same effect (21.56% and 19.10%). It has been established that the most favorable areas for the growth of J. deltoides are areas of very dry sub-bodies with a northeastern exposure of the slope.

Fractal Structure Characteristics and Prospecting Direction of Dispersed Metals in the Eastern Guizhou Pb–Zn Metallogenic Belt, SW China

The eastern Guizhou Pb–Zn metallogenic belt (EGMB) is an important source of Pb–Zn resources and other critical minerals (including dispersed metals, such as Ge, Cd and Ga) in China. In order to ensure the continuous resource supply of Pb–Zn and associated dispersed metals, it is urgent to explore the direction of further prospecting for them. Fractal theory can realize the fractal structure characterization of fault structures and the spatial distribution of mineral deposits, which is helpful for mineral exploration. However, the fault fractal research and prospecting application are still seldom covered in the EGMB. We used fractal theory to determine fine-scale fractal structure characteristics of fault structures and ore deposits in the EGMB, and Fry analysis to delineate favorable metallogenic areas. The results show that within a scale range of 3.670–58.716 km, the integrated faults capacity dimension (CPD) is 1.5095, the information dimension (IND) is 1.5391, and the correlation dimension (CRD) is 1.5436, indicating fault structures with high maturity, which are conducive to the migration and accumulation of ore-forming fluids. The multi-fractal spectrum width and height are 0.3203 and 1.5355, respectively, implying a significant metallogenic potential. The spatial distribution fractal dimensions (SDD) of Pb–Zn specifically and metal deposits in general are 1.0193 and 1.0709, respectively; the quantity distribution fractal dimensions (QDD) are 1.4225 and 1.4716, respectively, and the density distribution fractal dimensions (DDD) are 1.422 and 1.472, respectively, indicating strong clustering. Hence, the favorable metallogenic regions can be divided into four grades, among which grade I region is continuously distributed in space and has the greatest prospecting potential.

The Shadow Values of Soil Hydrological Properties in the Production Potential of Climatic Regionalization of the Czech Republic

The Czech Republic uses a dual system of agricultural land prices, namely the formal/official price—for tax purposes—and the market price in the case of a standard sale or purchase of farmland. This paper focuses on the construction of an econometric model to quantify the influence of soil hydrological characteristics on the production potential in a given climatic region. It also focuses on the use of this model for the determination of the official price of agricultural land, which is expressed on the basis of the code of the evaluated soil-ecological unit (ESEU) and based on defined soil characteristics. The pricing itself is based on the production potential of the land, which in practice is very important for spatial planning, as it determines the classes of agricultural land protection with regard to the possibility of setting aside agricultural land for non-productive purposes or for drawing subsidies for less favourable areas. In this context, the non-productive functions of agricultural land are also frequently discussed, especially its retention, which plays a very important role in the currently changing climatic conditions. There are a number of studies on soil retention, and numerous approaches to measuring it, but none of them address its impact on production potential and thus on the price of land. For this reason, this paper focuses on defining the influence of the retention of the main soil units (defined for the conditions of the Czech Republic) on production potential. For this definition, SUR models are used, where the endogenous variable is expressed as production potential and the exogenous variables include the basic soil characteristics such as grain size, porosity, hydrological component of the soil, and retention. The obtained outputs show both the high explanatory power of the model and the adequate parametric significance of most variables, which provides sufficient support for the use of the results in practice. In addition, the estimated models across all climatic regions are consistent with substantively logical assumptions about the link between production potential and soil hydrological properties, which secondarily demonstrates their applicability in practice, especially for state administration, but also for local government in the sense of municipalities, cities, and other organizational units.