Potential Reservoir Research Articles

Assessment of REY resource potential in deep-sea sediments with Fe–Mn (oxyhydr)oxides in the Pacific Ocean

Deep-sea sediments with an abundance bioapatites and Fe–Mn (oxyhydr)oxides in the Pacific Ocean have been considered potential reservoirs of rare earth elements and yttrium (REY). However, comprehensive assessment of the resource potential of REY in deep-sea sediments with Fe–Mn (oxyhydr)oxides throughout the Pacific Ocean is limited due to difficulties in accurately predicting the distribution of extensive Fe–Mn (oxyhydr)oxides and the associated REY. In this study, we predicted the prospective area and resource potential of REY-rich sediments with Fe–Mn (oxyhydr)oxides by considering multiple factors that control REY enrichment based on data from International Ocean Discovery Program (IODP) samples and previous research. According to the distribution map inferred by comprehensively evaluating lithology (clay sediment), hydrothermal fluid influence (δ3He), and water depth (bathymetry), deep-sea sediments with Fe–Mn (oxyhydr)oxides, which have higher than 1000 ppm REY concentration, are distributed in the vicinity of the East Pacific Ridge within a water depth range of 4000–4600 m, and their distribution area is estimated to be approximately 1.1 million km2. If the sedimentation rate (<1.5 m/Myr) is considered, which is a crucial factor influencing REY enrichment, we can achieve a more precise assessment of their distribution area. Assuming a recovery depth of only 1 m, the REY resource amount was estimated to be approximately >450 million tons of REY oxide. Even without accounting for REY resource amount associated with bioapatite, the minimum REY resource amount estimated in this study exceed the world's current land reserves. Furthermore, these sediments contain a significant abundance of industrially important heavy REY, accounting for 53 % of REY resources. This implies that the deep-sea sediments with Fe–Mn (oxyhydr)oxides in the Pacific Ocean are a promising resource of REY. Our findings will serve as essential information for the technological progress required in the exploration and development of REY resources in deep-sea sediments in the future.

A case-control study on risk factors for visceral leishmaniasis in West Pokot County, Kenya.

Visceral leishmaniasis (VL) is a severe parasitic disease transmitted by phlebotomine sandflies. VL is endemic in West Pokot County, Kenya, where effective strategies to interrupt transmission are impeded by the limited understanding of VL risk factors. Therefore, this case-control study aimed to explore environmental, behavioural and household determinants of VL in West Pokot. From November 2022 to January 2023, a structured questionnaire was administered to 36 symptomatic primary VL cases attending Kacheliba Sub-County Hospital in West Pokot and to 50 healthy controls from local villages. The VL status of all participants was confirmed using an rK39 rapid diagnostic test. Associations between questioned determinants and VL were investigated by means of age-corrected univariate logistic regression analysis. Significant associations were found between VL and housing characteristics, such as window presence and floor type. VL cases more frequently reported the presence of cattle, dogs and sheep in their house yards. VL was also associated with cutting down trees in the house yard and house proximity to several Acacia tree species. Furthermore, outdoor activities, including travelling outside the residence for more than 2 weeks, activities near termite mounds, and forest activities during the rainy season, increased the risk of VL. This work reports a number of previously undescribed risk factors for VL in the understudied West Pokot focus. The results suggest VL transmission occurs both peri-domestically at night and outdoors during the day, particularly when sandfly resting sites are disturbed. Our findings warrant further research into sandfly ecology and potential zoonotic parasite reservoirs in West Pokot.

Volcanic weathered crust reservoir analog: Insights from fault-controlled fracture permeability in the trachytic rocks of the Pernambuco Basin, NE Brazil

Naturally fractured volcanic rocks represent a globally significant potential hydrocarbon reservoirs and can also be used for CO2 storage; however, the study of volcanic reservoirs in Brazil is limited. Although numerous volcanic reservoir types have been classified, relatively few studies are dedicated to the weathering of crust-like reservoirs, i.e., volcanic rocks undergoing subaerially alteration by weathering prior to deep burial. This study aims to characterize a volcanic weathered crust reservoir analog located in the coastal zone of the Pernambuco Basin, NE Brazil. We applied a multiscale approach motivated by the expressive potential of volcanic rocks as reservoirs in this marginal basin and considered their implications for CO2 geological storage projects. The deformational aspects observed in this analog have also been observed in other volcanic rocks that crop out in the coastal zone, thus, the data provided here can guide future characterization of both onshore and offshore reservoirs. We focused on an 80 m wide outcrop and employed geometric and topological analysis of two-dimensional fracture networks to investigate the influence of regional fault zone control on the fracture permeability tensors. The parameters of fracture systems were studied using terrestrial gravimetric data, orthophoto mosaic obtained by an unmanned aerial vehicle (UAV), petrography, and outcrop-based structural data. The investigated outcrop includes porphyritic trachytes with euhedral sanidine crystals and minor quartz phenocrysts, sourced from the Ipojuca Magmatic Suite. The residual Bouguer map indicates the influence of at least two regional rift fault zones, i.e., NW-SE (strike-slip) and NE-SW (normal) trending systems, in the studied rocks. These trachytic rocks exhibited a marked dissolution of sanidine phenocrysts and matrix, columnar disjunctions, and natural fractures, causing the porosity and permeability of the reservoir analog to increase. Geometric and topological analyses showed that the south-central sector of the outcrop exhibits heightened connectivity within the fracture network. Furthermore, the principal fracture permeability is controlled by the primary families of the fracture network and regional fault zones. Our results demonstrate that the fracture network observed in the volcanic reservoir analog was influenced by the post-rift tectonic reactivation of Cretaceous structures within the Pernambuco Basin. The secondary porosity resulting from weathering and subsequent dissolution of the primary constituents and fractures of the rocks studied demonstrates the potential for the exploration of these reservoirs as models for known occurrences of volcanic rocks in the onshore and offshore domains of the Pernambuco Basin.

Experimental study on EOR potential of P(AM/NVP) based gel in ultra-high temperature reservoirs

Polymer gel has been widely used in high water cut reservoirs for enhanced oil recovery (EOR), while its effectiveness is often curtailed in ultra-high temperature reservoirs for the indeterminate stability. In the present work, the ultra-high temperature resistant gel was constructed with P(AM/NVP) as the main agent, hydroquinone and Polyethylenimine (PEI) as the crosslinking agent, and the EOR potential of P(AM/NVP) based gel is studied at 150 °C, including injectivity, plugging property, and oil increasing performance. The experimental results indicated that the base solution of P(AM/NVP) based gel could establish resistance factor of 17.5–182.5, the plugging rate of the gel exceeded 96%, and the breakthrough pressure gradient ranged from 17.99 MPa/m to 46.54 MPa/m in matrix cores. For fractured cores, the plugging ratio surpassed 95%, and the breakthrough pressure gradient decreased to 9.56 MPa/m ∼24.32 MPa/m. Moreover, within a permeability ratio of 5.90–28.75, the water cut could be decreased from 98.0%–100.0%–50.9%–65.81%, with an increase in oil recovery of 20.10%–44.30%. In addition, NMR experiment verified the gel blocking channeling channel and expand the sweeping efficiency of chase water flooding. This study's findings showed that P(AM/NVP) based gel has excellent EOR potential in ultra-high temperature reservoirs.

Whole genome sequence analysis reveals high genomic diversity and potential host-driven adaptations among multidrug-resistant Escherichia coli from pre-weaned dairy calves.

Food-producing animals such as dairy cattle are potential reservoirs of antimicrobial resistance (AMR), with multidrug-resistant (MDR) organisms such as Escherichia coli observed in higher frequency in young calves compared to older cattle. In this study, we characterized the genomes of enteric MDR E. coli from pre-weaned dairy calves with and without diarrhea and evaluated the influence of host-level factors on genomic composition. Whole genome sequence comparative analysis of E. coli (n = 43) revealed substantial genomic diversity that primarily clustered by sequence type and was minimally driven by calf diarrheal disease status (healthy, diarrheic, or recovered), antimicrobial exposure, and dietary zinc supplementation. Diverse AMR genes (ARGs)-including extended-spectrum beta-lactamase genes and quinolone resistance determinants-were identified (n = 40), with unique sets of ARGs co-occurring in gene clusters with large AMR plasmids IncA/C2 and IncFIB(AP001918). Zinc supplementation was not significantly associated with the selection of individual ARGs in E. coli, however analysis of ARG and metal resistance gene pairs identified positive associations between certain aminoglycoside, beta-lactam, sulfonamide, and trimethoprim ARGs with acid, tellurium and mercury resistance genes. Although E. coli in this study lacked the typical virulence factors of diarrheagenic strains, virulence genes overlapping with those in major pathotypes were identified. Among the 103 virulence genes detected, the highest abundance and diversity of genes corresponded to iron acquisition (siderophores and heme uptake). Our findings indicate that the host-level factors evaluated in this study were not key drivers of genomic variability, but that certain accessory genes in enteric MDR E. coli may be enriched. Collectively, this work provides insight into the genomic diversity and host-microbe interface of MDR E. coli from pre-weaned dairy calves.

Trait authenticity as an “enzyme” for personal resources and work engagement: A study among teachers within the framework of the job demands-resources model

IntroductionTrait authenticity has been defined as a dispositional individual difference, and it refers to people's experience of living in accordance with their true Self. Despite research conducted in working contexts has found that trait authenticity is related to people's work engagement, it is not clear if this association may be mediated by other variables. ObjectiveFraming trait authenticity within the job demands-resources model, we hypothesized that trait authenticity allows the release of human full potential in terms of personal resources that, in turn, promote work engagement, especially in highly challenging work settings, such as educational ones. MethodWe administered a self-report questionnaire composed of several measurement scales to 446 teachers working in kindergartens, primary schools, and middle schools. Results and conclusionsA moderated mediation analysis revealed that trait authenticity can promote teachers’ emergence of personal resources, which in turn enhances their work engagement. The study highlights that the role of trait authenticity and personal resources on work engagement acquires a particular salience when teachers face high (vs. low) challenge job demands (i.e., workload), that is when this reservoir of potential is needed the most.

Emergence of Virulent Extensively Drug-Resistant Vancomycin-Resistant Enterococci Among Diarrheic Pet Animals: A Possible Public Health Threat on the Move.

Background: Vancomycin-resistant enterococci (VRE) have become an increasing public health concern in the past few decades, being associated with serious multidrug-resistant (MDR) infections. This study was conducted to investigate the role of diarrheic pet animals as potential reservoirs for virulent extensively drug-resistant (XDR) VRE and their threat on human health. Materials and Methods: Rectal swabs were collected from 153 diarrheic pet animals (80 dogs and 73 cats). The collected swabs were cultured on CHROMagarTMVRE for the isolation of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium, and then suspected colonies were identified as enterococci after Gram staining, conventional biochemical tests, and molecular techniques. VRE were basically identified using the disk diffusion method; however, molecular identification of vanA and vanB genes was carried out among confirmed VRE isolates. Moreover, three virulence genes (cytolysin A, cylA; enterococcal surface protein, esp; and hyaluronidase, hyl) were investigated in VRE isolates. Thereafter, VRE strains that harbored virulence genes were tested for antimicrobial susceptibility. Results: Eighteen out of 153 animals (11.8%) were positive for VRE, which were obtained from 15% and 8.2% of the examined dogs and cats, respectively. None of the obtained isolates carried the vanA gene, whereas the vanB gene was detected in E. faecalis (4/10) with a prevalence rate (40%). Of the obtained VRE isolates, five possessed esp and/or cylA, while all strains were negative for the hyl gene. Furthermore, four virulent VRE isolates exhibited an XDR pattern, and one isolate was MDR. Conclusion: Diarrheic pet animals could represent a potential zoonotic reservoir for virulent XDR vancomycin-resistant E. faecalis, which may have serious public health implications.

Modelowe i empiryczne podejście do oceny parametrów petrofizycznych skał na przykładzie złoża gazu Dhodak w Pakistanie

The main aim of the presented study was to perform an analysis of petrophysical rock parameters for the Pab Formation, which is a potential reservoir, located at four-depth intervals within the Dhodak Gas Field. The Pab Formation in the studied wells is mostly composed of the well-sorted sandstone. The intervals for the study were selected by applying a gamma ray log cut-off of 40%. A Matlab code that is user-friendly and contains empirical and numerical models (Raymor’s, Han's, Castagna’s, Jizba, Blangy, and Gardner's models) was designed with the purpose of providing an interpretation of rock physics parameters in reservoirs. The results indicate that the Pab Formation is mainly saturated with hydrocarbons and possesses sufficient porosity (i.e. between 8 and 38%). According to the cross-plot models, there are a few zones within the Pab Formation that are weakly consolidated. These zones are located at depths of 2377–2404 m and 2418–2430 m. However, the same area is classified as tight gas sandstone and is located between 2330 to 2343 m. The results of the study indicate that the Pab Formation is potentially saturated with hydrocarbons. These findings were based on structural and rock physics assessments of the study area. The approach presented in this work is also helpful for structural trap evaluation. In addition, the petrophysical rock parameter models developed can contribute to reducing the risks associated with hydrocarbon exploration, enabling accurate representation of subsurface conditions and improving reservoir forecasting capabilities in oil producing areas.

Incidence of Chlamydia spp., FIV, FeLV in Free-Roaming Cats in Slovakia.

Free-roaming cats represent a potential reservoir of infectious diseases. The most common co-infections of free-roaming cats include mixed viral, bacterial, fungal, yeast and parasitic infections. This study focuses on the occurrence of Chlamydia spp. feline immunodeficiency virus (FIV), feline leukaemia virus (FeLV) and their co-infections. The diseases accompanied by immune suppression, such as FIV, create favourable conditions for the onset of other diseases and co-infections. The result of co-infection may be a higher susceptibility for other pathogens, as well as the occurrence of more severe clinical symptoms. The study involved 168 (113♀ and 55♂) free-roaming adult cats during the years 2021-2022. All cats belonged to Slovak citizens with permanent residence in the Slovak Republic. Blood samples and swabs (Invasive EUROTUBO® Collection sterile swab, Deltalab O8191 Rubí, Spain) from the conjunctival sac were taken from 168 cats to be later tested by PCR and ELISA methods. Statistical analysis was also performed. The overall prevalence of Chlamydia spp. was 17.26%, of FIV 15.48%, and 5.95% of FeLV. The most significant finding in our study was 3.57% co-infection of FIV and Chlamydia spp. in tested cats. The observed prevalence of Chlamydia spp. FIV and FeLV indicates that the presence of these pathogens in populations of free-roaming cats is endemic.

Integrated seismic, petrophysical, and geochemical studies for evaluating the petroleum system of the Upper Bahariya-Abu Roash G sequence in the Karama Field, Abu Gharadig Basin, North Western Desert, Egypt

The main aim of this study is to delineate the hydrocarbon potential and evaluate the petroleum system elements of the Cenomanian Abu Roash G (AR/G) and the Upper Bahariya Members in the Karama Field. It lies at the southeast borders of the Abu Gharadig Basin, a well-known basin in the W.D. to the NE of Africa. We accomplish this study by analyzing a total of thirty 2D seismic profiles, a complete data set of well logs for five wells, and their geochemical data. The workflow starts with illustrating the dominant subsurface structural features, defining the main potential reservoirs and their parameters, and checking the maturity of the probable source rocks. The seismic interpretation indicated that the research area had been influenced by a NE-SW anticlinal structure accompanied by a set of WNW-ESE and NW-SE normal faults that are controlled by the positive compression inversion process that dominated during the Late Cretaceous. Analyzing and processing the well log data sets suggest that the reservoirs of the Abu Roash G (AR/G) and the Upper Bahariya Members are characterized by poor to good reservoir settings with net-pay thickness reaching up to 13–50 feet in the different wells (av. Effective porosity (∅eff) = 17.7 % and 15.6% for the AR/G and the Upper Bahariya Members, av. Shale volume (Vsh) = 17.4 % and 13.6 %, av. Water saturation (Sw) = 38.9 % and 39.8 %, while av. Hydrocarbon saturation values (So) = 60.2 % and 61.1%, respectively). The geochemical and maturity analyses assisted in determining the potential mature source rocks of the Jurassic Khatatba Shale (TOC = 0.70–5.67%; S1+S2 = 0.43–5.97 mg/g, Ro = 0.54–1.06 %) with some contribution from the Cretaceous sources (Alam El-Bueib and Bahariya Formations). Studying elements of the petroleum regime of the Karama Field indicates that the trapped hydrocarbons are structurally controlled by three-way dip closures, horst blocks, sealing faults, and vertical sealing by impervious shale and limestone beds. This case study could be applied to similar analogs in other oil fields in the Egyptian Western Desert to delineate their hydrocarbon potential and structural setting.

The Derim Derim Dolerite, greater McArthur Basin, Australia: Using subsurface data to characterise a mesoproterozoic magma plumbing system

The application of high-resolution seismic reflection data has spurred major advances in knowledge of the emplacement of sub-volcanic mafic magma plumbing systems in sedimentary basins, highlighting the importance of interconnected sheet intrusions in facilitating lateral magma transport, the links between host rock mechanical properties and emplacement processes, and providing insights into how intrusive activity in basins impacts their resource potential. However, most studies have focused on Mesozoic-Cenozoic mafic magma plumbing systems situated along offshore rifted margins characterised by extensive subsurface datasets. The extensive Mesoproterozoic (c. 1300 Ma) Derim Derim Dolerite, which intrude the greater McArthur Basin in northern Australia, provide a unique opportunity to study the emplacement of a Proterozoic magma plumbing system due to its penetration by numerous hydrocarbon and mineral drillholes, in addition to seismic reflection coverage. Understanding the emplacement of this system is important because of its interactions with prospective unconventional shale reservoirs in the Velkerri and Kyalla Formations, which represent one of the world's oldest known petroleum systems. This paper focuses on characterising the intrusion emplacement and magma plumbing system using an array of subsurface data, to constrain the distribution, morphology, and emplacement mechanisms of the Derim Derim Dolerite.The morphology of the large, strata-concordant intrusions encountered at shallow present-day depths (<2 km) in the greater McArthur Basin is indicative of greater original emplacement depths of >3–4 km, suggesting a significant extent of uplift and erosion. Density-derived porosity values for the Velkerri and Kyalla Formations are anomalously low for their present-day depths, corroborating a greater palaeo-depth at time of emplacement. The extent of alteration of the host rock surrounding the Derim Derim Dolerite is highly variable, with a small number of occurrences of graphitisation of the organic matter adjacent to intrusions. However, this appears to be highly localised and the detrimental impact of the Derim Derim Dolerite on potential reservoir and/or source rocks appears generally minimal.

Quantifying water evaporation from large reservoirs: Implications for water management in water-stressed regions

Dam reservoirs are at the core of local water storage and supply, especially in water-stressed regions of the world with acute water shortage problems. However, evaporative losses from these reservoirs and their storage efficiency are often overlooked in water budgeting. We offer a mechanistic approach that combines physically-based modeling with remote sensing information of reservoir characteristics to reliably predict evaporative losses from dam reservoirs. The developed framework is used to predict evaporative water losses from potential dam reservoirs in different basins worldwide. We apply this framework to 10 of the largest dam reservoirs in the world's water-stressed regions to quantify evaporative water losses. Our analysis, spanning from 2000 to 2020, reveals considerable variations in annual evaporation rates in the reservoirs located in water-deprived regions exceeding 3200 mm/year during the study period with the total evaporative loss reaching 26.5 km3/year. The evaporative water loss accounts up to 15.8% of the storage capacity in one of the dam reservoirs, posing significant challenges for water allocation and conservation strategies, with notable economic and environmental consequences in regions already suffering from water scarcity.

Serosurveillance of Coxiella burnetii in feral swine populations of Hawai'i and Texas identifies overlap with human Q fever incidence.

Feral swine are invasive in the United States and a reservoir for infectious diseases. The increase in feral swine population and the geographic range are a concern for the spread of zoonotic diseases to humans and livestock. Feral swine could contribute to the spread of Coxiella burnetii, the causative agent of human Q fever. In this study, we characterized the seroprevalence of C. burnetii in feral swine populations of Hawai'i and Texas, which have low and high rates of human Q fever, respectively. Seropositivity rates were as high as 0.19% and 6.03% in Hawai'i and Texas, respectively, indicating that feral swine cannot be ruled out as a potential reservoir for disease transmission and spread. In Texas, we identified the overlap between seropositivity of feral swine and human Q fever incidence. These results indicate that there is a potentially low but detectable risk of C. burnetii exposure associated with feral swine populations in Hawai'i and Texas.

Microscopic marvels: Decoding the role of micropeptides in innate immunity.

The innate immune response is under selection pressures from changing environments and pathogens. While sequence evolution can be studied by comparing rates of amino acid mutations within and between species, how a gene's birth and death contribute to the evolution of immunity is less known. Short open reading frames, once regarded as untranslated or transcriptional noise, can often produce micropeptides of <100 amino acids with a wide array of biological functions. Some micropeptide sequences are well conserved, whereas others have no evolutionary conservation, potentially representing new functional compounds that arise from species-specific adaptations. To date, few reports have described the discovery of novel micropeptides of the innate immune system. The diversity of immune-related micropeptides is a blind spot for gene and functional annotation. Immune-related micropeptides represent a potential reservoir of untapped compounds for understanding and treating disease. This review consolidates what is currently known about the evolution and function of innate immune-related micropeptides to facilitate their investigation.

Identification of ticks and tick-borne pathogens of wildlife necropsy cases submitted to the SANBI National Zoological Gardens, South Africa

Ticks are arachnid blood-feeding parasites, which infest livestock, wildlife, and humans, transmitting medically and veterinary significant pathogens. Their biodiversity and distribution in wild animals remains complex. This study analysed archived tick samples (n = 48) from the South African Biodiversity Institute (SANBI) Wildlife Biobank utilizing morphology and genetic analyses of the 16S rRNA and COI (DNA barcoding) mitochondrial genes to identify ticks collected among 13 vertebratesavian, reptilian, and mammalian host species. The specimens came from nine localities including nature reserves and captive facilities (zoological garden) in South Africa, Namibia, and Botswana. These ticks were also assessed for associated pathogens with the reverse line blot (RLB) hybridization assay. Seven tick genera, Amblyomma, Hyalomma, Haemaphysalis, Ixodes, Rhipicephalus, Rhipicentor, and Otobius were identified, with Amblyomma being the most prevalent (22.9 %) in our sample set.Obtained sequences were 95–100 % similar to published records of tick species collected from wild and domestic animals, as well as those collected from vegetation, from different southern African areas. However, tick specimens (n = 3) identified morphologically as Hyalomma truncatum, Rhipicephalus e. evertsi, and R. simus, were, on a molecularly level, more closely related to their sister taxa (H. glabrum, R. e. mimeticus, and R. gertrudae, respectively) suggesting a need for taxonomic verification. With the RLB hybridization assay, six samples reacted with the Ehrlichia/Anaplasma genus-specific probe, while two reacted with the Theileria/Babesia genus-specific probe. Sequencing of the RLB amplicons targeting the 18S rRNA gene (n = 2) indicated 100 % similarity to Hepatozoon fitzsimonsi, while one was closely related to He. ingwe with 99.39 % similarity. The results show that wildlife harbour different tick species, and pathogen detection identified novel genotypes, indicating wildlife as potential pathogens reservoirs. This study enhances our understanding of tick biodiversity, distribution and highlights wildlife's role in harbouring diverse tick species and novel pathogens.

Seroepidemiology of bovine herpesvirus-1 in goats in south-western Iran.

Widely regarded as one of the chief causes of diseases in cattle population, bovine herpesvirus-1 (BoHV-1) has the potential to infect sheep and goat, making them potential reservoirs or hosts for this virus. Thus, preventive measures against BoHV-1 in cattle should not overlook the ability of this virus to infect other animals. Therefore, the focal point of this study was to ascertain the seroprevalence of BoHV-1 in 300 healthy goats, the relationship between host and the environmental determinants of infection, and the contributing role of goats in the epidemiology of the BoHV-1. In order to pinpoint the existing antibodies to BoHV-1, the obtained sera were analyzed by Virus Neutralization test. According to this test, the seroprevalence of BoHV-1 appeared to be 64.33% in southwestern Iran. What logistic regression disclosed was that the odds ratio between age and infection with BoHV-1 was 0.83 (p=0.01), representing a decrease of 17% as goats grew one year older. In addition, females manifested a higher relative frequency of infection compared to males, with the odds of infection in female goats being registered at 1.88, compared to those in males (p=0.2). Moreover, contrasted with goats lacking any history of abortion, those with a history of abortion featured 1.1 as the odds ratio (p=0.87). The seroprevalence in Hendijan, Ahvaz, Shushtar and Dasht e Azadegan was detected to stand at 73.24, 71.30, 55.56 and 47.06 percent, respectively, with 6% of fluctuation in the infection rates being attributed to various geographical locations under the scrutiny of this study (p=0.003). Having attested the marked seroprevalence of BoHV-1, the definitive role of goats in the epidemiology of this virus as a secondary host or reservoir was confirmed by the present study, necessitating the strict monitoring of BoHV-1 in goats by animal health authorities in areas where BoHV-1 abounds in cattle.

Genetically divergent 'Candidatus Phytoplasma solani' isolates in Croatian vineyard pathosystems suggest complex epidemiological networks

'Candidatus Phytoplasma solani’ (CPs), a phytoplasma endemic to the Euro-Mediterranean basin is a causative agent of several plant diseases, including the grapevine yellows disease “bois noir” (BN). As different CPs strains have been shown to have different ecological reservoirs and pathways for spread, the genetic characterization of CPs strains is a prerequisite, and better control of BN relies on the identification of reservoir plants. The variability of the phytoplasma genotypes involved in the BN pathosystem in Croatian vineyards was assessed by a multilocus sequence typing (MLST) approach. The genotyping was performed on selected grapevine, wild plants, and insects collected within the eleven years of national survey conducted in all Croatian viticultural regions. The extensive tuf, secY, stamp, and vmp1 genes-based MLST analyses revealed two new genotypes for stamp and vmp1 genes, designated as ST59 and V28, respectively, and overall identified 28 different CPs MLST genotypes. The prevalent MLST genotype in grapevine CPsSqt21 (S6/ST6/V18/tuf-b2) was widespread in nine counties across Uplands, Slavonia, and Danube wine regions and was affiliated to the known vector Hyalesthes obsoletus and to Urtica dioica. The other two most frequent genotypes were the U. dioica-associated CPsSqt28 (S39/ST46/V3/tuf-a) and the C. arvensis-associated CPsSqt2 (S1/ST9/V4/tuf-b1). CPs of different vmp1 genotypes was also detected in Cixius wagneri specimens originating from different parts of Croatia. In addition, CPs was detected in several Dichtyophara europaea insects and in two new potential plant reservoirs Ailanthus altissima and Robinia pseudoacacia. The substantial number of found MLST genotypes indicates the presence of several independent epidemiological cycles and is certainly a consequence of a unique geographical position of Croatia, bridging the different eco-climatic areas of central and south-eastern Europe.

Petrophysical characterization of the Late-Cretaceous Logbaba Formation in the Kribi/Campo sub-basin, Cameroon: Implication on deep-water hydrocarbon exploration

Deep-water hydrocarbon exploration in the Kribi/Campo sub-basin offshore Cameroon is targeting the promising Campanian-Maastrichtian turbidite reservoirs. However, a detailed understanding of the petrophysical properties of these Upper Cretaceous reservoirs is not well documented. In this study, well logs from two boreholes W1 and W2 located in the southern part of the sub-basin provide a unique opportunity to assess the reservoir quality of the Upper Cretaceous Logbaba Formation. Four potential reservoir intervals with thickness ranging between 27 and 105.7 m were delineated in W1, compared with two intervals in W2 with thickness ranging between 72.2 and 93.6 m. Lithological analysis of these reservoir intervals indicates a heterogeneous reservoir matrix consisting of sand, limestone, and dolomite. These reservoir intervals are interpreted as turbidite sand deposits with a clay content ranging from 6.3 to 19.8%, porosity ranging from 15.5 to 21.3%, permeability ranging between 5.65 and 75.09 mD and a water saturation of 34.5–74.2%. Fluid free index, reservoir quality index, and flow zone indicator are insignificant and suggest reservoirs with poor transmissibility. These analyses reflects good petrophysical characteristics for the sandstones of Logbaba Formation. However, both wells were water-bearing with non-mobile hydrocarbon residuals and did not contain commercial quantities of hydrocarbons. There is no evidence of hydrocarbon migration in either reservoir, suggesting that the source rock and the hydrocarbon migration pathways are the main risk factors and reason for the failure of the wells. The findings from this study extend the understanding of the reservoir characteristics of the Upper Cretaceous Logbaba Formation, which will further enhance hydrocarbon prospectivity offshore Cameroon. Since these reservoirs are water-laden, they may serve as potential offshore saline aquifers for geological storage of CO2 offshore Cameroon.

Experimental geochemical assessment of a seal-reservoir system exposed to supercritical CO2: A case study from the Ebro Basin, Spain

This paper studies the effects of exposure to CO2-rich brine on sandstones and marls considered potential deep storage reservoir and seal in the Ebro Basin, Spain.The experiment was conducted in a reactor under conditions of deep saline formations (pressure 8 MPa, temperature 313 K, exposure time 30 days, and CO2-supersaturated seawater ≈0.80 Mol). Both exposed and non-exposed samples were characterised by means of Optical Microscopy, Scanning Electronic Microscopy, X-ray Diffraction and Digital Image Analysis. Furthermore, powdered samples were analysed chemically trough X-ray Fluorescence, and brine samples were subjected to chemical analysis.The petrographic study of adjacent sandstone samples before and after the exposure to CO2-rich brine indicates an increase in porosity (≈3 %). These changes in pore structure are the result of mineral dissolution (e.g., siliceous cement) and intergranular matrix detachment and its partial removal from the rock sample, representing the initial effects induced by the CO2-rich brine. The chemical analysis of the brine reveals an increase in Ca2+ and SiO2 composition (29 % and 6670 %, respectively). After marl exposure, the brine also exhibited increased Ca2+and SiO2 content (95 % and 11,250 %, respectively), indicating the prevalence of dissolution processes.These results suggest that in environments where CO2 enriches the brine the mixture primarily induces localized chemical adjustments in the rocks (evidenced by dissolutions in the brine). The proposed methodology can be adapted for similar experimental batch tests in other storage structures.

Research on the water flooding front based on dynamic and static data inversion – a case study

To clarify the movement of the water flooding front in fluvial reservoirs, this research takes the BZ oilfield as an example. By considering the equivalent flow resistance theory for oil–water two-phase flow, the horizontal micro-element equivalent method and the strong heterogeneity of fluvial facies reservoir comprehensively, a calculation model for a non-piston water flooding front in a horizontal well pattern was established. First, five horizontal injection–production well groups in the BZ oilfield were taken as examples to calculate the water breakthrough time for the oil wells. The calculation results are in good agreement with the actual production performance. In detail, the advancing speed of the water flooding front in the high-permeability strip was 0.8–1.6 m/day, and the speed in the low-permeability strip was 0.12–0.35 m/day. When water is seen in the oil well, the advancing speed in the low-permeability strip is reduced, resulting in uneven displacement and the formation of non-dominant potential areas. In addition, the water flooding front advancing distance was simulated to be 300–450 m by establishing a reservoir numerical simulation model, which is close to the result of the proposed model, indicating that the calculation method is reliable. This research is of great significance for predicting the water breakthrough time of horizontal production wells, judging the weak affected area on the mainstream line, and optimizing water injection and tapping reservoir potential in good time.