Original Reservoir Research Articles

State of Zooplankton and Zoobenthos of the Water Bodies of the Pyasino Lake Basin after a Man-Made Accident<sup>1</sup>

The taxonomic composition and quantitative characteristics of zooplankton and zoobenthos of some reservoirs of natural origin of the Norilsk industrial district and adjacent territories after a man-made accident have been determined. In most sample collection points, all age groups of many invertebrates are marked. The Daldykan River above the confluence of the Bezymianny Сreek and the source of the Pyasina River represent a poorly disturbed watercourses and can serve as a norm for organizing recovery activities.

Tectonic Control on Shale Pore Structure and Gas Content from the Longmaxi Formation Shale in Southern Sichuan Basin, China: Insights from Fractal Analysis and Low-Pressure Gas Adsorption

Tectonic deformation of different intensities significantly controls shale pore structure, seepage channels, and gas content. The Longmaxi Formation shales in the southern Sichuan Basin have experienced multi-stage tectonic movements, resulting in a diverse fracture system and tectonic deformation. This study focuses on three representative tectonic morphologies: deeply buried strongly deformed (DBSD), deeply buried weakly deformed (DBWD) and shallowly buried weakly deformed (LBWD). We investigated the pore structure characteristics and heterogeneity of these shales under various tectonic conditions using total organic carbon (TOC) content, X-ray diffraction (XRD), scanning electron microscopy (SEM), a low-pressure N2/CO2 adsorption experiment (LP-N2/CO2 GA), and multi-scale fractal theory. The results reveal that strong tectonic compression and deformation conditions lead to the compression and flattening of organic pores by brittle minerals, resulting in long, oriented OM pores. Fracturing of brittle pore creates multiple internal fracture systems linked to dissolution pores, forming a complex micro-fracture–pore network. With intense tectonic deformation, mesopores tend to be compressed, increasing micropore pore volume (PV) and surface area (SA). The DBSD shale exhibits the highest micropore heterogeneity, while the LBWD shale shows the lowest heterogeneity. Fractal analysis indicates a significant decrease in micropore fractal dimension (Df) with increasing burial depth. In contrast, the surface and matrix fractal dimensions (Ds and Dm) of low-buried shale micropores and meso-macropores align vertically. Shale reservoirs in tectonically stable regions exhibit more favourable gas-bearing characteristics than strongly tectonically deformed areas. The LBWD has stable tectonic conditions that are favourable for shale gas preservation. Conversely, slip faults under deep burial conditions lead to extrusion and deformation of shale pore space, ultimately compromising the original reservoir capacity and hindering shale gas enrichment. These findings contribute significantly to our understanding of pore structure and heterogeneity in tectonically deformed shale reservoirs, providing invaluable guidance for the exploration, development, and prediction of shale gas resources.

Zoonoses in a changing world.

Animals are continuously exposed to pathogens but rarely get infected, because pathogens must overcome barriers to establish successful infections. Ongoing planetary changes affect factors relevant for such infections, such as pathogen pressure and pathogen exposure. The replacement of wildlife with domestic animals shrinks the original host reservoirs, whereas expanding agricultural frontiers lead to increased contact between natural and altered ecosystems, increasing pathogen exposure and reducing the area where the original hosts can live. Climate change alters species' distributions and phenology, pathogens included, resulting in exposure to pathogens that have colonized or recolonized new areas. Globalization leads to unwilling movement of and exposure to pathogens. Because people and domestic animals are overdominant planetwide, there is increased selective pressure for pathogens to infect them. Nature conservation measures can slow down but not fully prevent spillovers. Additional and enhanced surveillance methods in potential spillover hotspots should improve early detection and allow swifter responses to emerging outbreaks.

Simulation Calculation and Analysis of Connate Water Convection on Steam Chamber Expansion in Steam-Assisted Gravity-Drainage Process

Steam-assisted-gravity-drainage (SAGD) is a widely employed method to enhance heavy oil production and efficiency, and the key to ensuring its steady operation is the maintenance of a steam chamber. Heat conduction and convection of steam to connate water are essential factors in the heat transfer process. In this paper, we developed a novel analytical model to investigate the heat transfer process on the boundary of the steam chamber, driven by the pressure difference between the injected steam and the original reservoir. Both conduction and convection are considered in this new model, and the calculated results are in good agreement with the simulated data by using CMG-STARS. After model validation, the effects of physical properties and operating conditions (relative permeability, initial water saturation, and steam temperature) on the heat transfer process are investigated. The results reveal that connate water saturation plays a large role than the steam temperature in conductive heat flux; low saturation leads to more efficient crude oil exploitation. This work provides new insights into the recovery mechanisms of a SAGD process.

Characterizing the molecular epidemiology of anaesthesia work area transmission of Staphylococcus aureus sequence type 5

Staphylococcus aureus sequence type 5 (ST5) is an emerging global threat. To characterize the epidemiology of ST5 transmission in the anaesthesia work area. The retrospective cohort study analysed transmitted, prophylactic antibiotic-resistant Staphylococcus aureus isolates involving anaesthesia work area reservoirs. Using whole-genome analysis, the epidemiology of ST5 transmission was characterized by reservoir(s) of origin, transmission location(s), portal of entry, and mode(s) of transmission. All patients were followed for at least 30 days for surgical site infection (SSI) development. Forty-one percent (18/44; 95% confidence interval: 28-56%) of isolates were ST5. Provider hands were the reservoir of origin for 28% (5/18) of transmitted ST5 vs 4% (1/26) for other STs. Provider hands were the transmission location for 28% (5/18) of ST5 vs 7% (2/26) of other STs. Stopcock contamination occurred for 8% (1/13) of ST5 isolates vs 12% (3/25) of other STs. Sixty-three percent of transmission events occurring between cases on separate operative dates involved ST5. ST5 was more likely to harbour resistance traits (ST5 median (interquartile range) 3 (2-3) vs 2 (1-2) other STs; P < 0.001) and had greater resistance to cefazolin, piperacillin-tazobactam, and/or ciprofloxacin (ST5: 3 (2-3) vs 2 (1-3) other STs; P = 0.02). ST5 was associated with three of six SSIs. ST5 is prevalent among transmitted, prophylactic antibiotic-resistant isolates in the anaesthesia work area. Transmission involves provider hands and one patient to another on future date(s). ST5 is associated with a greater number of resistance traits and reduced in-vitro susceptibility vs other intraoperative meticillin-resistant S.aureus.

Analysis of SARS-CoV-2 variants from patient specimens in Nevada from October 2020 to August 2021.

In early 2020, the emergence and spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the human population quickly developed into a global pandemic. SARS-CoV-2 is the etiological agent of coronavirus disease 2019 (COVID-19) which has a broad range of respiratory illnesses. As the virus circulates, it acquires nucleotide changes. These mutations are potentially due to the inherent differences in the selection pressures within the human population compared to the original zoonotic reservoir of SARS-CoV-2 and formerly naïve humans. The acquired mutations will most likely be neutral, but some may have implications for viral transmission, disease severity and resistance to therapies or vaccines. This is a follow-up study from our early report (Hartley et al. J Genet Genomics. 01202021;48(1):40-51) which detected a rare variant (nsp12, RdRp P323F) circulating within Nevada in mid 2020 at high frequency. The primary goals of the current study were to determine the phylogenetic relationship of the SARS-CoV-2 genomes within Nevada and to determine if there are any unusual variants within Nevada compared to the current database of SARS-CoV-2 sequences. Whole genome sequencing and analysis of SARS-CoV-2 from 425 positively identified nasopharyngeal/nasal swab specimens were performed from October 2020 to August 2021 to determine any variants that could result in potential escape from current therapeutics. Our analysis focused on nucleotide mutations that generated amino acid variations in the viral Spike (S) protein, Receptor binding domain (RBD) and the RNA-dependent RNA-polymerase (RdRp) complex. The data indicate that SARS-CoV-2 sequences from Nevada did not contain any unusual variants that had not been previously reported. Additionally, we did not detect the previously identified the RdRp P323F variant in any of the samples. This suggests that the rare variant we detected before was only able to circulate because of the stay-at-home orders and semi-isolation experience during the early months of the pandemic. IMPORTANCE: SARS-COV-2 continues to circulate in the human population. In this study, SARS-CoV-2 positive nasopharyngeal/nasal swab samples were used for whole genome sequencing to determine the phylogenetic relationship of SARS-CoV-2 sequences within Nevada from October 2020 to August 2021. The resulting data is being added to a continually growing database of SARS-CoV-2 sequences that will be important for understanding the transmission and evolution of the virus as it spreads around the globe.

Multi-objective optimal reservoir operation considering algal bloom control in reservoirs

Reservoir operation strategies (ROSs) are considered an efficient and low-cost method to control algal blooms. However, reservoir operations must consider regular objectives, including flood prevention and power generation. To address this multi-objective optimization problem, we coupled the non-dominated sorting genetic algorithm-II (NSGA-II) model and the General Lake Model-Aquatic EcoDynamics library (GLM-AED) model to optimize reservoir operations. Taking the Zipingpu Reservoir as a case study, we found the peak of outflow discharge (POD) could be reduced from 1059.5 to 861.4 m3 s−1 (19%), the total power generation (TPG) could be increased from 6.6 × 108 to 7.1 × 108 kW h (8%), and the peak of chlorophyll a concentration (PCC) could be decreased from 42.7 to 27.2 μg L−1 (36%) compared with the original reservoir operation in the early flood period. The obtained Pareto frontier revealed the tradeoffs between algal bloom control, flood prevention, and power generation. Reservoir operation schemes that achieved low PCC were typically associated with large POD and moderate TPG. In particular, under fixed start and end water levels, maintaining a higher average water level during May and June could result in larger outflows, effectively inhibiting algal accumulation and bloom development, thereby leading to a lower PCC. Slight variations in average water age were found among the minimum PCC scheme, maximum TPG scheme, and minimum POD scheme, indicating that water exchange varied little and has not been responsible for the differences in PCC. Collectively, enhancing outflow was determined to play a vital role in reducing PCC, particularly when operating under constrained rules. These findings contribute new insights into optimal reservoir operations considering algal bloom control and emphasize the importance of enhancing outflow as a governing mechanism. Furthermore, the coupled model offers a transferable technical framework for reservoir managers to mitigate eutrophication through ROSs.

Experimental measurements and response analysis of resistivity of reservoirs with complex wettability: A case study of Yan’an Formation, Ordos Basin, China

Resistivity logs are commonly used to distinguish oil and water reservoirs. However, the complex hydrocarbon accumulation pattern in the study area leads to complex wettability, which significantly affects the resistivity as well as the density and neutron logs and causes difficulties in fluid-type identification. To understand the resistivity characteristics and accurately identify the fluid types, resistivity experiments of core samples selected by the density and neutron logs are performed. The nuclear magnetic resonance (NMR) is simultaneously measured to determine the rock wettability. Instead of the conventional “aged” method for restoring the original wettability, a new set of experimental procedures is developed for obtaining resistivity and NMR [Formula: see text] spectra of samples with wettability as close as possible to that of the original reservoir. Specifically, samples with and without oil washing are measured separately, and a simple correction method for the resistivity index is developed. Moreover, the difference in the water salinity of different wells is considered. The results find that the resistivity index of samples drilled from possible oil-wet reservoirs indicated by the “abnormal” density and neutron responses varied from 2.807 to 5.388, whereas that of possible water-wet reservoirs was less than 2.0. The [Formula: see text] spectra at different states confirm the wettability of the samples. The resistivity index versus saturation ([Formula: see text]–[Formula: see text]) curves of oil-wet rocks are nearly straight lines other than the theoretical concave lines in double-logarithmic coordinates. Oil washing changes the rock wettability to varying degrees. Furthermore, the resistivity log responses of the reservoirs are accurately interpreted using the experimental data. The resistivity is simultaneously affected by the salinity, wettability, and saturation. Finally, based on the factors affecting the reservoir resistivity, fluid identification plots are established for reservoirs with different wettabilities. The agreement rates of identification using the crossplots and oil test are greater than 90%.

Determination of adsorption parameters in shale gas resource/reserve calculation: Case study of Wufeng Formation–Longmaxi Formation in the Sichuan Basin

In the calculation of shale gas resources/reserves, isothermal adsorption parameters are mainly determined by dry sample data at the laboratory temperature, and the regression effect of total organic carbon content (TOC) isothermal adsorption parameters is poor. Based on the physical significance of key parameters in Langmuir and Henry adsorption models, the problems in determining the isothermal adsorption parameters in the calculation of shale gas reserves/reserves are analyzed by taking the marine shale in the Upper Ordovician Wufeng Forming–Lower Silurian Longmaxi Formation in the Sichuan Basin as an example. Based on a large number of measured isothermal adsorption data, the effects of TOC, temperature and water saturation on the shale gas adsorption parameters are analyzed. The influence model of TOC, temperature and water saturation on isothermal adsorption parameters of shale gas is established, and a novel method for calculating the adsorption parameters of shale gas from under experimental conditions to original reservoir conditions is proposed. The results are obtained as follows. First, there are problems in the calculation of shale gas resources/reserves, such as poor and contradictory fitting relation between isothermal adsorption parameters and TOC, difficulty in the conversion of Van't Hoff equation, and difficulty in direct application of water saturation (Sw) in resource/reserves calculation. Second, the problem of poor direct fitting relation between Langmuir pressure (pL) and TOC is solved by integrating the Langmuir adsorption model with the Henry adsorption model and by establishing a new parameter – Henry constant a for methane adsorption capacity of shale. Third, when Sw<40%, the Langmuir volume (VL) is linearly negatively correlated with Sw; when Sw<20%, a is constant relatively; by establishing the relationship between the normalized absolute adsorption capacity and Sw (<50%) under the pressure exceeding 30 MPa, the effect of Sw on the isothermal adsorption capacity can be calculated. Fourth, the in-situ stress in the Wufeng Formation–Longmaxi Formation shale reservoir affects the adsorption capacity of shale. For shale reservoirs with the same TOC, the higher the in-situ stress, the smaller the VL and a values. Under high pressure (>30 MPa), the effect of Sw on the methane adsorption capacity of shale shows a similar trend, and the effect of water molecules on the adsorption capacity on shale pore surface is constant. It is concluded that the proposed novel method for determining the isothermal adsorption parameters of shale with different TOC, temperature and water saturation conditions provides a technical support for the accurate calculation of shale gas resources/reserves and contributes to the scientific development of shale gas industry.

(498) Take it or Leave it? Comparison Between Drain and Retain Versus Reservoir Recycling in Inflatable Penile Prothesis Revision

Abstract Introduction There are three strategies for managing an implanted urologic reservoir during inflatable penile prothesis (IPP) revision. The original reservoir can be removed, deactivated and left in place (drain and retain), or validated and reconnected to an IPP system (reservoir recycling). Although complete removal of a reservoir would prevent the potential complications of a retained device, the formation of a surrounding fibrotic capsule leads to complete removal being less popular among providers compared to drain and retain or reservoir recycling. We sought to evaluate the long-term complications and efficacy of these approaches. Objective To compare the efficacy and safety of the drain and retain and reservoir recycle approaches to IPP revision against the gold standard of full device replacement. Methods We performed a retrospective chart review of our large, single-surgeon tertiary referral center penile prosthesis database between 2007-2022 to identify all individuals with a retained or recycled reservoir. Only those who had undergone appropriate follow-up and had complete documentation about reservoir handling were included in the study. Reservoir-related complications, mechanical failures, and device infections were compared between the retained, recycled, and full replacement groups using a chi-square test. Mean follow-up duration, time to revision, and operative time were assessed using a Student’s T-test. Results There were 140 patients who met inclusion criteria with 48 retained reservoirs, 30 recycled reservoirs, and 62 full replacements. The average age of a reservoir when it was recycled was 4.3 years. Retained and recycled reservoir groups had similar mean follow-up duration, time to revision, and intraoperative time when compared to the full replacement group (Table). Most reservoirs (91% of retained, 90% of recycled, 90% of full replacement) were implanted using the high submuscular technique. Our institution’s virgin IPP implant infection rate was 2.6%. When compared to the full replacement group, infection, mechanical failure, and revision rates were similar for both the retained and recycled reservoir groups (Table and Figure). There was only one verified post-revision reservoir leakage from a recycled reservoir, but no instances of reservoir herniation or reservoir-related bowel complications between the three groups. Conclusions There was no difference in reservoir-related complications, mechanical failure, or infections when comparing the drain and retain or reservoir recycle groups to the full replacement group. Reservoir drain and retain and recycling are both safe and effective management options in IPP revision surgery. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Boston Scientific, Coloplast.

A decision-making method for reservoir operation schemes based on deep learning and whale optimization algorithm.

Reservoir operation is an important part of basin water resources management. The rational use of reservoir operation scheme can not only enhance the capacity of flood control and disaster reduction in the basin, but also improve the efficiency of water use and give full play to the comprehensive role the reservoir. The conventional decision-making method of reservoir operation scheme is computationally large, subjectivity and difficult to capture the nonlinear relationship. To solve these problems, this paper proposes a reservoir operation scheme decision-making model IWGAN-IWOA-CNN based on artificial intelligence and deep learning technology. In view of the lack of data in the original reservoir operation scheme and the limited improvement of data characteristics by the traditional data augmentation algorithm, an improved generative adversarial network algorithm (IWGAN) is proposed. IWGAN uses the loss function which integrates Wasserstein distance, gradient penalty and difference item, and dynamically adds random noise in the process of model training. The whale optimization algorithm is improved by introducing Logistic chaotic mapping to initialize population, non-linear convergence factor and adaptive weights, and Levy flight perturbation strategy. The improved whale optimization algorithm (IWOA) is used to optimize hyperparameters of convolutional neural networks (CNN), so as to obtain the best parameters for model prediction. The experimental results show that the data generated by IWGAN has certain representation ability and high quality; IWOA has faster convergence speed, higher convergence accuracy and better stability; IWGAN-IWOA-CNN model has higher prediction accuracy and reliability of scheme selection.

Thermal and hydrodynamic analysis of a self-purging hot reservoir variable conductance heat pipe

A new design of a hot reservoir variable conductance heat pipe (VCHP) is proposed and investigated in this study. While a hot reservoir VCHP can provide much tighter thermal control performance in comparison to a traditional cold reservoir VCHP, it was seen that the hot reservoir design is prone to more common operating failures due to the accumulation of the working fluid inside the reservoir. Once accumulated, this excessive working fluid in the reservoir can only be removed by diffusion which takes a long time. In this study, we propose and investigate a new design for the hot reservoir VCHP that would perform an additional function of working fluid vapor purging in addition to operating as a normal heat pipe. In the proposed design, the non-condensable gas (NCG) section of the heat pipe is connected to the reservoir by an external tube, forming a NCG flow-inducing loop configuration, hence the name self-purging hot reservoir VCHP (SPHR-VCHP). With proper placement of the NCG pipe in the VCHP a pressure-induced flow is generated through the loop from the NCG section towards the reservoir. It is shown that this loop flow can remove the excess working fluid vapor in the reservoir significantly faster than by diffusion. A Fortran code to simulate the two-phase flow in the heat pipe section combined with an ANSYS Fluent CFD model of the external loop is employed to predict the fluid flow, heat transfer, and mass transfer behaviors inside the SPHR-VCHP. An experiment is set up for the SPHR-VCHP that is made of a 291 mm long titanium tube with an inner diameter of 14.7 mm. The working fluid and the NCG are acetone and helium, respectively. The CFD predictions of wall temperature are validated by the experimental data with mean absolute error equal to 2.68%. A thorough CFD study is then performed to optimize the loop design in order to enhance purging rates by changing the size of the NCG tube to operate under microgravity conditions for space applications. Based on this study an optimum NCG pipe diameter equal to 40% of the inner diameter and pipe length equal to the length of the evaporator section is suggested. The wall temperature results show that the SPHR-VCHP design does not impact the thermal performance of the original hot reservoir heat pipe, while also having a self-purging capability that makes the design safe from working fluid accumulations issues.

Dynamics of the parasitofaauna of roach Rutilus rutilus (Linnaeus, 1758) since the beginning of the existence of the Boguchanskoye reservoir

This article presents the results of parasitological studies of roach Rutilus rutilus (Linnaeus, 1758) in Boguchanskoye reservoir, the stages of parasite fauna formation and the current state of the reservoir. Ichthyofauna of Boguchanskoye Reservoir was formed by local fauna of Angara River. Transformation of the original reservoir has led to significant changes in the composition and community structure of all groups of organisms of aquatic biota and affected the parasite fauna of fish. Over eight years (2012–2020), 35 species of parasites from 9 classes were recorded in roach in Boguchanskoye Reservoir. Originally, the composition of parasites was not diverse and had few specific species. Most parasites had low or single occurrence. Trematode metacercariae predominated, and their quantitative indicators (extensity of infection and index of abundance) indicate the ecological confinement of fish to shallow river sections. After impoundment, the parasite fauna composition became more diverse due to parasitic protozoa and monogeneas. Currently, the proportion of parasites with a direct development cycle is 68.2%. In 2020, two types of helminths were registered with a plankton development pathway: Ligula intestinalis Linnaeus, 1758 and Philometra rischta Skrjabin, 1917. The species Ph. rischta — first detected in fish in water bodies of Krasnoyarsk Region. There was a change in the dominant species, Dactylogyrus crucifer (Wagener, 1857) became the dominant species.

ОБОСНОВАНИЕ ТЕХНИЧЕСКИХ ТРЕБОВАНИЙ К РОБОТОТЕХНИЧЕСКОМУ КОМПЛЕКСУ МНОГОРЕЖИМНОГО ПОЖАРОТУШЕНИЯ

The purpose of the study is to substantiate the technical requirements for a robotic complexdesigned to eliminate man-made emergencies associated with the need to eliminate fires. Theseemergencies can occur, first of all, in radiation and chemical accidents, as well as in accidents atfire and explosion hazardous facilities. The elimination of such emergencies, as a rule, is associatedwith an increased risk for firefighters and rescuers and requires the use of heavy equipment.The article proposes a campaign that involves considering two possible options for using the complex:when extinguishing a fire over an area in the modes of a single cycle with a transportablesupply of water and when extinguishing fires in a long-term fire extinguishing mode. At the sametime, it is proposed to consider the areal fire extinguishing rate and water consumption as the main indicators for assessing the effectiveness of the complex. Under the areal rate of fire extinguishing,it is proposed to understand as the ratio of the fire extinguishing area to the time. Waterconsumption during fire extinguishing is a single value for all links in a serial chain, in the form ofwhich a scheme for supplying water to a fire source can be represented. For the first option, theamount of water flow is sequentially calculated, which depends on the pressure that is created infront of the water shaft. This indicator primarily depends on such factors as the water pressuregenerated by the pump, the pressure loss in the hose line, the excess or decrease of the water barrelin relation to the pump. According to the results of calculations for each link, the obtainedindicators are summarized. For the second option, the capabilities of the robotic complex for longtermfire extinguishing involve the use of an existing reservoir of natural or artificial origin as asource of fire extinguishing agent. At the same time, the number of factors affecting the areal rateof fire extinguishing and water consumption increases significantly. To simplify the calculations, anomogram has been developed that allows you to calculate not only the above indicators, but alsodetermine the predicted values of the time required to extinguish the fire. The data obtained as aresult of the above calculations make it possible to finally realize the main task of the studies underconsideration, that is assessment of the capabilities of a promising complex of a robotic complexfor extinguishing fires at radiation-, chemical- and explosive objects. This problem is proposedto be solved by forming the technical forms of the RTK, which can be created to solve firesat the above objects, and then by a comparative assessment of their qualities.

Carbon Isotope Fractionation Characteristics of Normally Pressured Shale Gas from the Southeastern Margin of the Sichuan Basin; Insights into Shale Gas Storage Mechanisms

Since the development of shale gas in the Wufeng-Longmaxi Formation in the Sichuan Basin, China's shale gas production and reserves have increased rapidly. The southeastern margin of the Sichuan Basin is located in a normally pressured transition zone, where single well gas production varies greatly under complex geological structures. In order to reveal the shale gas enrichment mechanism and favorable shale gas regions, shale gas samples from production wells were collected from different structures, with the formation pressure coefficient ranging between 0.98 and 1.35. The gas components and carbon isotope characteristics of normally pressured shale gas were investigated. The carbon isotope characteristics of the Wufeng-Longmaxi shale gas from the basin scale was mainly controlled using thermal maturity; as the thermal maturity increased, heavier carbon isotopes were found, in addition to drier shale gas. For normally pressured shale gas, the composition of δ13C1 and δ13C2 becomes heavier, and the dryness coefficient decreases with the decreasing pressure coefficient; this is not consistent with the results from thermal evolution. By comparing possible influencing factors, it is evident that the change in geological structure destroys the original shale gas reservoir, which leads to the escape of some gases, and it may be the main factor that contributes to the gas geochemical characteristics of the normally pressured shale gas. Compared with the geological parameters of the shale samples, such as mineral composition, organic abundance, organic pore distribution, and gas content, the carbon isotope characteristics of normally pressured shale gas show a higher efficiency, thus indicating favorable sweet spot evaluations for shale gas in the studied areas.

Distribution and ecology of Wolffia arrhiza (L.) Horkel ex Wimm. In the lowland part of Lower Silesia (Poland)

Genus Wolfia Horkel ex Schleiden (Araceae, former Lemnaceae) includes 11 species that are the smallest of known flowering plants. The genus is widespread in the world. In Europe, the only native species is Wolffia arrhiza. In Poland, it is considered to be relatively rare and until the end of the 20th century it was known from small number of populations dispersed throughout the country Poland. Our research focused on Lower Silesia population of Wolffia arrhiza. The study included the verification of historical sites of this species known from the literature and an inventory of the contemporary occurrence. It also aimed to explain the pattern of W. arrhiza occurrence in selected habitats and determine the ecological conditions and phytocoenoses of the reservoirs it inhabits. The research of the species showed extinction of historical sites and the current presence in 12 water reservoirs of different origin, size, depth and management method. The share of W. arrhiza in phytocoenosis patches in the individual reservoirs is very diverse and ranges from 15 to 80%. Presented data supplement the information on the occurrence of W. arrhiza in western Poland as well as provide new information on its biology and ecology.

Study on fracture development and progressive failure characteristics of downstream dam-type expansion tailings reservoir

With the economic development and industrialization, the increasingly accumulated tailings ponds in China have become a great risk. Due to the difficulty of selecting proper site for a new reservoir in Yunnan, a sub-dam was built at the downstream original reservoir. This study explored the fracture development and progressive failure characteristics of the tailings reservoir area after capacity expansion based on a similarity experiment and the numerical simulation. The results showed that the primary cracks in the reservoir area were more than those at the top of the sub-dam. With the increase of the upper load, the primary cracks further developed and penetrated the whole sub-dam top, and the sub-cracks were then produced under the concentrate stress of the primary cracks. After the further development of the sub-cracks, the secondary cracks parallel to the primary cracks were formed on the outer slope of the sub-dam. The progressive failure of a tailings dam can be summarized as: the maximum shear stress was firstly generated at the toe of the slope or the top of the dam which then extended to the top of the sub-dam in the form of a curve and finally formed the failure surface by connecting with the primary fracture of the tensile plastic zone at the top of the dam. The study also found that in the process of tailings accumulation in the new reservoir area, tailings would form "back pressure slope protection" at the initial dam of the original reservoir, which not only effectively delayed the occurrence of shear failure, but also inhibited the generation and penetration of tensile plastic zone.

A generalized reservoir module for SWAT applications in watersheds regulated by reservoirs

Accurate estimates of reservoir outflow are important for simulating runoff of watersheds regulated by large reservoirs using hydrological models. The target release reservoir module widely used in the Soil and Water Assessment Tool (SWAT) shows poor performance in simulating the outflow and water level of large multipurpose reservoirs. In this study, a generalized reservoir operation chart-based reservoir module is developed as an alternative to the original reservoir module in SWAT (SWAT-Or). The proposed reservoir module includes a dynamic decision-based outflow framework integrated into the operation chart. The modified version of SWAT with the new reservoir module (SWAT-M) is not only suite for small reservoir with flood control function but also more applicable to large multipurpose reservoir. The predictions obtained from the original and new reservoir modules are compared with measured data from the three largest reservoirs in the Dongjiang River basin, South China. The performance of SWAT-M and SWAT-OR for daily and monthly runoff simulations of four hydrological stations in the basin are compared. The results shows that the proposed module produces results closer to the field measurements and has fewer errors than the original module, which predicts inappropriate low reservoir outflow during dry periods. In addition, the runoff simulation by SWAT-M shows a significant improvement, in particular for stations directly influenced by large reservoirs. The monthly (daily) scale R2 of SWAT-M is 0.02 to 0.21 (0.14 to 0.44) higher, and the NSE is 0.11 to 0.30 (0.12 to 7.16) higher than that of SWAT-Or. The proposed reservoir operation chart-based module significantly improves the applicability of SWAT to simulate runoff in watersheds regulated by large reservoirs.

Formation mechanism and hydrocarbon exploration significance of the box fold in the Qiulitage structural belt, the Kuqa Depression, Tarim Basin, China

Clarifying the deformation characteristics and formation mechanisms of the box fold in the eastern Qiulitage structural belt can provide important references for the reconstruction of the evolution process and petroleum exploration in the Qiulitage structural belt. As a result of the deep geological structure displayed by seismic data and characteristics of faults and fractures within the box fold, the mechanical mechanism and structural evolution of the box fold in the eastern Qiulitage structural belt were investigated, along with the genesis and significance of hydrocarbon exploration of faults and fractures within the box fold. The results show that the surface box fold in the Qiulitage structural belt was formed via the conjugate kinking of the supra-salt structural layer, driven by the intensive southward compression during the Middle and Late Himalayan movements. The box fold has experienced three evolution stages, namely, the tectonically-inactive stage before the deposition of the Kuqa Formation, the fold rudiment stage during the early to middle deposition of the Kuqa Formation (Kuqa period), and the stage of fold finalization and uplift-denudation. The front flank of the box fold develops north-dipping thrust faults and network fracture systems formed during the early to middle Kuqa period and cemented by gypsum due to the precipitation of deep, high-salinity formation water. However, later faulting can cut and dislocate the cement. The upper fold core develops north-dipping tensile faults and near EW tensile fractures, while the lower fold core is associated with small back-thrust structures and near NS shear fractures. The neutral plane is expected to be in the middle-lower part of the fold. The back-flank of the box fold develops south-dipping back-thrust faults and near EW interlayer shear fractures caused via interlayer detachment. The core and back flank of the fold were less affected by the high-salinity formation water, leaving faults and fractures with no considerable cementation. The kink zone and its surroundings have high storage and flow capacities and thus the potential to and develop oil and gas reservoirs. Correctly interpreting kink zones in concealed areas can help expand the scale of original oil and gas reservoirs or discover new petroleum exploration domains. In the Qiulitage structural belt, the connection between deep and shallow fault systems leads to the migration of deep hydrocarbons to shallow layers and subsequent accumulation. The structural-lithologic oil and gas reservoir formed in the Paleogene thin sand layers of the upper part of the Lower Cretaceous and the structural oil and gas reservoir formed in supra-salt sandstone layers of the surface box fold are among The potential exploration domains in shallow layers.

Automatic topology optimization of echo state network based on particle swarm optimization

The task of time series forecasting is to predict the future trend of data based on the collected historical data, providing theoretical and data support for human judgment and decision making. Randomization-based echo state networks (ESNs) are widely used in the research and application field of time series analysis for their simple structure and fast training speed. The core of the ESN is its dynamic reservoir, which the original reservoir are randomly generated and controlled only by parameter sparsity, often performing poorly on complex tasks and affecting the performance of networks. Manual design of the topology of reservoir is difficult, time-consuming and inconvenient to operate, which is not conducive to the development of ESNs. The construction of a suitable reservoir topology for practical application problems to enrich reservoir dynamics is a hot research point for researchers. In this paper, an automatic optimization method is introduced into the topology optimization of ESN (TP-ESN), and the particle swarm optimization algorithm is used to optimize the topological construction of the ESN. The connection structure between the reservoir neurons is first encoded and then iteratively optimized. The optimized structure is decoded and then the reservoir is initialized for ESN training. Prediction results on Mackey–Glass benchmark time series and two electroencephalogram (EEG) datasets demonstrate that TP-ESN method can have better adaptability, stronger prediction ability and stability than several other manually designed ESN reservoir topologies in the case of relatively complex tasks.