Reservoir Location Research Articles

The Rigicon Infla10® IPP implantation via the penoscrotal and subcoronal approaches: The UKSH experience

ABSTRACT Introduction Penile implant manufacturers compete to introduce the latest technologies within their devices. They all aim to develop the optimal implant with the best functionality and highest durability. One of the relatively new companies that has recently joined the competition is Rigicon which has lately introduced its new Infla10® inflatable penile prosthesis (IPP). This video was recorded at the University Hospital Campus Kiel, Germany which is one of the first European centers of excellence to implant Rigicon devices. Objective The German experience with the new Infla10® penile implant, represented by the Kiel School of Prosthetic Urology, is demonstrated via a step-by-step instructive video of two penile prostheses implantations. While elaborating the steps of the procedures, we highlight the various unique features of the new Infla10® device related to the cylinders, reservoir, and pump. Methods We utilized the penoscrotal approach for our first patient and the subcoronal approach for our second. For our first implantation, we chose the high submuscular reservoir location leaving the traditional retropubic reservoir implantation for our second patient. Results Both patients demonstrated an eventless surgery and postoperative follow-up period and were satisfied with their implants. Conclusions We consider the Infla10® device to be a promising addition to the available devices in the market. The Infla10® implant comprises a number of advanced device technologies that add to both the durability and reliability of the implant. Disclosure Work supported by industry: no. A consultant, employee (part time or full time) or shareholder is among the authors (Coloplast).

Experimental measurements of monopole inner/outer collar waves and estimation of P wave velocity in acoustic LWD

Acoustic logging while drilling (LWD) technology is extensively applied for petroleum prospecting. It utilizes the acoustic characteristics of stratum to deduce the formation properties such as porosity, permeability, and oil saturation, etc., which can help to detect the location of oil reservoirs. In acoustic logging process, the formation longitudinal (P) and transverse (S) wave velocity is the primary factor of interest. Nevertheless, an accurate identification of P/S wave velocity in different formations is hard to be performed due to the influence of the collar waves, which has become an urgent problem in LWD measurements. To study this issue more practically, a small-sized measurement system based on the propagation mechanism of collar waves is established in our laboratory. With this system, we design and perform multiple sets of monopole acoustic LWD experiments with different models. After recording the experimental data, the attenuations of inner and outer collar waves received along the axial direction are compared and analyzed. The result shows that the collar waves have an exponential decay in amplitude by the expansion of source-receiver distance, but the outer collar wave decreases more rapidly. We also conduct experiments at different source frequencies (20–400 kHz) to quantitatively describe the relationship between the amplitude and frequency. The result suggests that the inner/outer collar waves and P/S waves have a similar frequency response, and it's difficult to remove collar waves from the full waveforms of LWD signals by only changing source frequency. Therefore, we present a new data processing method for extracting the formation wave velocities according to the energy distribution of the componential waves, and then apply it in the analysis of two borehole measurements. The inner and outer collar waves are almost removed from the processed time domain waveforms, which leads to a successful verification of formation P/S wave velocities. These experimental results prove the feasibility and repeatability of our method, and propose an alternative method for the LWD data explanations.

Radiographic Assessment of Inflatable Penile Prosthesis Reservoir Location Variability in Contemporary Practice

ABSTRACT Introduction Inflatable penile prosthesis (IPP) reservoirs are typically placed into the Space of Retzius (SOR), High Submuscular Space (HSM), or alternative locations via a transinguinal (TI) approach or a lower abdominal counter incision (CI). A cadaver study showed variability in reservoir location after TI-HSM placement (JSM: 2016 Sep;13(9):1425-1431). Objective We sought to evaluate reservoir location using cross-sectional imaging following contemporary IPP insertion. Methods We retrospectively reviewed our institutional database and identified men who underwent virgin penoscrotal IPP insertion from 2007 to 2019. We then identified those men who subsequently underwent cross-sectional imaging prior to October 2019. Radiologists blinded to reservoir placement technique evaluated cross-sectional imaging and categorized each reservoir location in relation to the abdominal wall musculature, transversalis fascia, and peritoneum. Statistical analysis was performed using Chi-squared and Fisher's exact tests. Results Among 561 men who underwent virgin IPP insertion during the 12 year study period, 114 had cross-sectional imaging subsequently obtained: 29 TI-SOR, 80 TI-HSM, and 5 CI-HSM (Table). TI-HSM reservoirs were more likely than TI-SOR to be located anterior to the transversalis fascia (14 vs. 48%, p=0.001). TI-HSM reservoirs were less likely than TI-SOR to be located in the preperitoneal space (62 vs. 18%, p<0.001). Rates of retroperitoneal reservoir location were similar between the TI-HSM and TI-SOR groups. Among all 561 patients (131 TI-SOR, 405 TI-HSM, and 25 CI-HSM), rates of reservoir-related complications requiring operative intervention were similar between groups (5 vs. 2 vs. 0%, p = 0.24). Conclusions Roughly half of the TI-HSM reservoirs in this series appeared to be located posterior to the transversalis fascia on cross-sectional imaging. Although preperitoneal and retroperitoneal locations were common in both groups, reservoir related complications were rare. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Boston Scientific and Coloplast

Boston Scientific vs. Coloplast: A Prospective Analysis of a Single High-volume Surgeon's Inflatable Penile Prosthesis Experience

ABSTRACT Introduction Surgical implantation of a penile prosthesis may be offered to patients with erectile dysfunction (ED) as primary treatment or after failed therapy. The two FDA approved three-piece inflatable penile prostheses (IPPs) on the market, the AMS (American Medical Systems) 700TM series (Boston Scientific, Massachusetts) and the Coloplast Titan® (Coloplast, Minnesota), differ in their overall design and anti-microbial coating. However, little is known as to whether these differences have an impact on risk of infection or revision. Objective To compare the likelihood of infection and short-term revision in IPP placements performed by a single high-volume surgeon when using Boston Scientific's AMS 700TM series versus Coloplast Titan® implants. Methods We performed a prospective analysis of a single IPP surgeon's experience with AMS 700TM and Titan® at two private hospitals between January 2017 and December 2019. The surgeon alternated the implants every other week for comparison. Data was collected on patient demographics, implant characteristics, case duration, and complications. Results A total of 542 patients (mean age 69.2 years) underwent 548 IPP implantations during the two-year period. Of the 548 cases, 303 (55.3%) implantations were performed using Boston Scientific AMS 700TM while 245 (44.7%) were with Coloplast Titan®. Only one (0.18%) case was complicated by post-operative infection despite drain placement for three days in all 548 cases. This infection occurred in a Coloplast Titan® placed as a revision for SST deformity. Seven (1.3%) cases ultimately required revision by the time of review. Although five of the seven cases requiring revision were done using AMS 700TM implants, this did not amount to a statistically significant increase in risk compared to Titan® (p=0.39). First revisions of AMS 700TM were noted to be done earlier than Titan® on average (225 days vs. 450 days postoperatively, p=0.42). Overall, the most common reason for revision was tube fracture (n=3). Diabetes, case time, performing hospital, reservoir type, and reservoir location were not significant prognostic factors for revision (p>0.05). Conclusions Risk of infection or short-term revision is not impacted by whether the IPP is manufactured by Coloplast or Boston Scientific. A high-volume IPP surgeon has a significantly decreased risk of infection and revision compared to those currently published in the literature. Disclosure No

Significance of sandstone provenance in tracking potential uranium reservoirs: A case study of the Middle Jurassic Zhiluo Formation, western Ordos Basin, northern China

The Middle Jurassic Zhiluo Formation is the main uranium-bearing sequence in the western Ordos Basin, northern China. Provenance studies of clastic rocks in the Zhiluo Formation are important to provide guidelines for uranium exploration. In this paper, we describe the sandstones from the Zhiluo Formation and report their bulk rock elemental compositions by using samples that were collected from the Lingwu area, western Ordos Basin. Our main objective is to provide constraints on the provenance of the sandstones and thus new insights into uranium exploration. The results show that the sources of the Zhiluo Formation sandstones have TTG (trondhjemite-tonalite-granodiorite) attributes and mainly consist of magmatic arc orogenic belts that were mixed with continental blocks and recycled orogenic belt materials. The paleocurrent measurements that average 144° suggest that the provenance supply direction of the sandstones is from northwest to southeast. Combined with the regional tectonic settings, it can be inferred that the sandstone provenance was mainly provided by the Xingmeng Orogenic Belt, while the Alxa Block and Helan Mountain complex rocks also contributed. Our research might provide a crucial reference for predicting the locations of potential uranium reservoirs, i.e., the search for uranium mineralization should target the northwest of the Ordos Basin, especially near regions where intermediate-acid rocks are present. This information is integrated into a predictive model in which tracking along the provenance supply directions of clastic sediments is an efficient method for conducting uranium exploration in a sedimentary basin.

Effects of a cascade reservoir system on runoff and sediment yields in a River Basin of southwestern China

In the upper reach of the Yangtze River Basin in China, changes of the runoff and sediment yield in the middle reach of the Jinsha River Basin have been given close attentions because of their declination trends over recent years. Then, the impact factors for the variations of runoff and sediment yield were urgent need to be investigated through a distributed hydrological modelling under multi spatiotemporal scales. The results showed that climate change had a significant impact on runoff and sediment yield of the basin before the operation of cascade reservoirs. The contribution rate of the reservoirs operation to the reduction of the annual runoff and sediment yield in the watershed was 48.90% and 28.75% respectively. The Ludila reservoir played an important role in reducing annual runoff and sediment yield of the basin. The location of reservoirs with the sequence of Ludila, Longkaikou, Jin'anqiao, and Ahai from upstream to downstream had the greatest effect on the annual sediment yield of the basin. The function of multiple reservoirs on the monthly runoff and sediment yield of the basin was not the superposition of a single one. Under the simultaneous change of temperature and precipitation, the precipitation had a greater impact on runoff and sediment yield of the basin than temperature. Spatially, the annual runoff and sediment yield in the middle and upper reaches of the basin were sensitive to changes of temperature and precipitation. This research provides scientific support for management of water and sediment resources in watersheds with cascade reservoirs.

Possible consequences of climate change on global water resources stored in dam reservoirs

Construction of dams and transformation of rivers, not only affects river-related and adjacent habitats, but also establishes new threats to surface freshwater resources globally. Predicted climate changes and increase of mean annual temperature will affect thermal regimes of dam reservoir ecosystems, severely altering their functioning. Analyzing three projections of representative concentration pathway (RCP 4.5, 6.0 and 8.5) for period of 2061–2080, we found that mean annual temperature at dam reservoir locations will increase by 3.06 °C to 4.74 °C from present. The highest projected increase of temperature was identified for dam reservoirs located in high latitudes of Northern Hemisphere, and therefore dam reservoirs located there will be most significantly affected. Numerous consequences of temperature increase are already recorded. Further increase will amplify unfavorable effects on numerous ecosystems, including dam reservoirs which are built on the purpose of the human population development. Our study indicates a threat for artificially stored water globally, with special attention to high latitudes in northern hemisphere and latitudes close to 200S meridian in southern hemisphere.

A New Fluid Mobility Calculation Method Based on Frequency-Dependent AVO Inversion

Fluid mobility (i.e., permeability to viscosity ratio) is a key parameter that can evaluate the reservoir permeability and delineate the fluid characteristic in hydrocarbon-saturated reservoirs. Based on the asymptotic representation for the frequency-dependent reflections in the fluid-saturated pore-elastic media and frequency-dependent AVO inversion, we propose a novel method for estimating fluid mobility from poststack seismic data. First, we establish the relationship between fluid mobility and frequency-dependent AVO analysis. Then, the fluid mobility is estimated using the theory of frequency-dependent AVO inversion. Tests on synthetic data reveal that the fluid mobility shows excellent imageability for the fluid-saturated reservoirs and can accurately delineate the spatial distribution shape of the gas-saturated reservoir. The application of field data examples demonstrates that the fluid mobility calculated by the proposed method produces less background interferences caused by elastic layers compared with the conventional frequency-dependent fluid indicator. The frequency-dependent fluid mobility takes into account the dispersion features associated with hydrocarbon reservoirs, and it provides a new way to detect the location of hydrocarbon reservoirs and characterize their spatial distribution.

PyGEE-SWToolbox: A Python Jupyter Notebook Toolbox for Interactive Surface Water Mapping and Analysis Using Google Earth Engine

Continuous monitoring of surface water resources is often challenging due to the lack of monitoring systems in remote areas and the high spatial distribution of water bodies. The Google Earth Engine (GEE) platform, which houses a large set of remote sensing datasets and geospatial processing power, has been applied in various aspects of surface water resources monitoring to solve some of the challenges. PyGEE-SWToolbox is a freely available Google Earth Engine-enabled open-source toolbox developed with Python to be run in Jupyter Notebooks that provides an easy-to-use graphical user interface (GUI) that enables the user to obtain time series of Landsat, Sentinel-1, and Sentinel-2 satellite imagery, pre-process them, and extract surface water using water indices, such as the Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), Automated Water Extraction Index (AWEI), and Dynamic Surface Water Extent (DSWE). The validation of the toolbox is carried out at four reservoir and lake locations: Elephant Butte Lake, Hubbard Creek Reservoir, Clearwater Lake, and Neversink Reservoir in the United States. A time series of the water surface area generated from PyGEE-SWToolbox compared to the observed surface areas yielded good results, with R2 ranging between 0.63 and 0.99 for Elephant Butte Lake, Hubbard Creek Reservoir, and Clearwater Lake except the Neversink Reservoir with a maximum R2 of 0.52. The purpose of PyGEE-SWToolbox is to provide water resource managers, engineers, researchers, and students a user-friendly environment to utilize the GEE platform for water resource monitoring and generation of datasets. The toolbox is accompanied by a step-by-step user manual and Readme documentation for installation and usage.

Use of drones to determine potential locations of reservoir to anticipate water crisis in Weninggalih Village, Jonggol District, Bogor Regency, West Java

Weninggalih village experiences drought that keeps recurring every year which has an impact on the people in the area. The purpose of this study was to determine the potential location for the construction of a reservoir to anticipate water crisis in Weninggalih Village, Jonggol Districts, Bogor Regency. The research method used is a survey method to determine the sampling location and quantitative methods are used for analysis. The field survey used a drones for aerial photo data recording. Sampling was determined purposively based on the Digital Elevation Model in three dimensions from the resulting aerial photos. Quantitative methods are used to determine the potential location of the reservoir. The results showed that there were 6.609 photos taken with the drone flying at a height of 150 meters above ground level with 80% overlap. Based on the results show that there are three potential locations of reservoirs. The first potential sites of reservoir is in the area of 423 m2. The second one potential sites of reservoirs 1.415 m2 and the last one potential site of reservoirs are in area three land area of 1.191 m2.

Satellite-derived cyanobacteria frequency and magnitude in headwaters & near-dam reservoir surface waters of the Southern U.S.

Reservoirs are dominant features of the modern hydrologic landscape and provide vital services. However, the unique morphology of reservoirs can create suitable conditions for excessive algae growth and associated cyanobacteria blooms in shallow in-flow reservoir locations by providing warm water environments with relatively high nutrient inputs, deposition, and nutrient storage. Cyanobacteria harmful algal blooms (cyanoHAB) are costly water management issues and bloom recurrence is associated with economic costs and negative impacts to human, animal, and environmental health. As cyanoHAB occurrence varies substantially within different regions of a water body, understanding in-lake cyanoHAB spatial dynamics is essential to guide reservoir monitoring and mitigate potential public exposure to cyanotoxins. Cloud-based computational processing power and high temporal frequency of satellites enables advanced pixel-based spatial analysis of cyanoHAB frequency and quantitative assessment of reservoir headwater in-flows compared to near-dam surface waters of individual reservoirs. Additionally, extensive spatial coverage of satellite imagery allows for evaluation of spatial trends across many dozens of reservoir sites. Surface water cyanobacteria concentrations for sixty reservoirs in the southern U.S. were estimated using 300 m resolution European Space Agency (ESA) Ocean and Land Colour Instrument (OLCI) satellite sensor for a five year period (May 2016–April 2021). Of the reservoirs studied, spatial analysis of OLCI data revealed 98% had more frequent cyanoHAB occurrence above the concentration of >100,000 cells/mL in headwaters compared to near-dam surface waters (P < 0.001). Headwaters exhibited greater seasonal variability with more frequent and higher magnitude cyanoHABs occurring mid-summer to fall. Examination of reservoirs identified extremely high concentration cyanobacteria events (>1,000,000 cells/mL) occurring in 70% of headwater locations while only 30% of near-dam locations exceeded this threshold. Wilcoxon signed-rank tests of cyanoHAB magnitudes using paired-observations (dates with observations in both a reservoir's headwater and near-dam locations) confirmed significantly higher concentrations in headwater versus near-dam locations (p < 0.001).

Estimating melt fraction in silicic systems using Bayesian inversion of magnetotelluric data

The location, volume and physical states of magma reservoirs are primary controls on the eruptive behavior of volcanic systems. Fundamental to understanding and monitoring these systems is the ability to identify reservoir size and physical properties, in particular melt fraction which plays an important role in the rheology and stability of a magmatic system. Large silicic volcanic eruptions in the geological record suggest that extensive pockets of melt-rich silicic magma must exist in the subsurface but such melt pockets have not been detected by geophysics. This has led to the question of whether the reservoirs that feed large volcanic eruptions are only melt-rich for a short time and thus would only be detected by geophysics shortly prior to an eruption. Magnetotelluric data measure the electrical resistivity of the subsurface and are sensitive to subsurface fluids and partial melts making it a powerful tool for imaging subvolcanic magma reservoirs. This study examines the ability for magnetotelluric data to accurately estimate melt fraction using both stochastic Bayesian inversion and deterministic regularized inversion. Results from synthetic modelling indicate that magnetotelluric data are best able to predict the melt fraction for the thick melt-rich layer using both inversion methods, though both methods under-estimate the true amount of melt. In addition, magnetotelluric data can accurately detect changes in melt fraction from crystal-rich mush (0.1 melt fraction) to melt-rich magma (0.9 melt fraction) for thick layers. Thickness is a key parameter which provides a method to assess the total volume of melt present, but it is difficult to estimate using smooth regularized inversions. Fixed-dimension Bayesian inversions provide estimates of layer thickness and their uncertainties and it is shown that estimates of total volume of melt are more accurate for both thin (0.2 km) and thick (1 km) layers than individual estimates of melt fraction or thickness alone. The melt fraction of the thin melt-rich layer is under-estimated using both the deterministic inversion method and the most probable solution of the Bayesian inversion. The Bayesian distribution of solutions has long tails which includes the true solution and better represents the uncertainty of the modelled parameters. As we consider past large melt-rich caldera eruptions at Taupo (New Zealand), Toba (Indonesia), Yellowstone and Long Valley (USA), our analysis suggests that thin melt-rich, potentially eruptible zones involved in large (e.g. >500 km3) eruptions could be systematically misinterpreted as thicker non-eruptible crystal-rich mush zones. Testing the sensitivity of MT to detect melt accumulation in active magmatic systems has important implications for volcanic hazard assessment and the use of Bayesian inversions allows for a better understanding of the range of possible interpretations.

Mapping environmental suitability of Haemagogus and Sabethes spp. mosquitoes to understand sylvatic transmission risk of yellow fever virus in Brazil.

BackgroundYellow fever (YF) is an arboviral disease which is endemic to Brazil due to a sylvatic transmission cycle maintained by infected mosquito vectors, non-human primate (NHP) hosts, and humans. Despite the existence of an effective vaccine, recent sporadic YF epidemics have underscored concerns about sylvatic vector surveillance, as very little is known about their spatial distribution. Here, we model and map the environmental suitability of YF’s main vectors in Brazil, Haemagogus spp. and Sabethes spp., and use human population and NHP data to identify locations prone to transmission and spillover risk.Methodology/Principal findingsWe compiled a comprehensive set of occurrence records on Hg. janthinomys, Hg. leucocelaenus, and Sabethes spp. from 1991–2019 using primary and secondary data sources. Linking these data with selected environmental and land-cover variables, we adopted a stacked regression ensemble modelling approach (elastic-net regularized GLM, extreme gradient boosted regression trees, and random forest) to predict the environmental suitability of these species across Brazil at a 1 km x 1 km resolution. We show that while suitability for each species varies spatially, high suitability for all species was predicted in the Southeastern region where recent outbreaks have occurred. By integrating data on NHP host reservoirs and human populations, our risk maps further highlight municipalities within the region that are prone to transmission and spillover.Conclusions/SignificanceOur maps of sylvatic vector suitability can help elucidate potential locations of sylvatic reservoirs and be used as a tool to help mitigate risk of future YF outbreaks and assist in vector surveillance. Furthermore, at-risk regions identified from our work could help disease control and elucidate gaps in vaccination coverage and NHP host surveillance.

Karstified layers and caves formed by superposed epigenic dissolution along subaerial unconformities in carbonate rocks – Impact on reservoir-scale permeability

Superposed events of rock exposure, fracturing, and the hydrological dynamics, are key elements that influence epigenic karstification in carbonate reservoirs. However, they are not fully identified in seismic or well data. One way forward is a multiscale characterization of the porous system to understand karst development, from the pore scale to large caves, confined to high-permeability layers that can reach the basin scale. The present study investigates superposed meteoric dissolution events in carbonate rocks by combining the analyses of depositional setting, diagenesis, stratigraphic architecture, tectonics, and hydrological zones. We performed analyses of 130 plugs collected in 11 outcrops using petrographic, petrophysical, mineralogical, and geochemical analyses. The study area is the Cretaceous Jandaíra Formation in the Potiguar Basin, Brazil, where we identified a regional subaerial unconformity-SU (sequence boundary-1). This surface is characterized by a change in facies and depositional system between dolomitic peritidal deposits (depositional sequence 1) and tight-cemented calcite subtidal deposits (depositional sequence 2). A concentration of caves occurs below the SU. We conclude that subaerial unconformities (vadose surfaces) can develop better reservoir qualities with superposed freshwater leaching and karstification. They control the lateral reservoir zonation, whereas faults and fractures provide vertical pore distribution within the vadose/phreatic hydrological zones. Water table fluctuations can develop multilevel caves and conduits along the epiphreatic zones, increasing the reservoir thickness, which reaches 50–100 m in the Potiguar Basin. We recognized two previous subaerial unconformities at the basin scale using well and seismic data. These findings may have important implications for assessing reservoir location and quality in large areas.

СТРОЕНИЕ ВОДОНОСНЫХ ГОРИЗОНТОВ ПО АНОМАЛИЯМ МАГНИТНОГО ПОЛЯ И СИЛЫ ТЯЖЕСТИ

The results of the study of the main characteristics and structural features of the aquifer systems of cold and thermal waters on the example of well-known sources in the Middle East are presented. The study of groundwater aquifers was carried out on the basis of the technology of geophysical data complex interpretation, taking into account the features of the aquifers geological structure. Aquifers and underground reservoirs are visualized as zones of reduced magnetization and density of rocks on deep petrophysical sections calculated from magnetic field and gravity anomalies. Horizontal subterranean water conduits can be clearly traced on the areal distributions of magnetization and density along the stretches of the lineaments with reduced values. Vertical subterranean water conduits stand out vividly on magnetic and density sections in the form of ascending tracks. As a result of the study of deep sections through the zones of known thermal springs, an estimate of the dependence of the source temperature on the depth of the feeding underground reservoirs was obtained. The article examines the potential of underground resources aquifers of the arid territories of Israel, the Kingdom of Saudi Arabia and the United Arab Emirates, for which the relevance of the water problem, apparently, will not decrease in the coming decades. The forecast of the location of groundwater karst reservoirs can be carried out by magnetic and density sections, taking into account two-dimensional models of the distribution of magnetization and density of rocks. The methodology of the study of aquifer systems is applicable to the analysis of underground resources of Africa and the Middle East arid regions.

Stress behavior of hydrate-bearing sands with changing temperature and hydrate saturation

Since the natural gas hydrate (NGH) was confirmed to be widespread in deep-sea strata and permafrost regions, NGH research arouses great enthusiasm among scholars, and the commercial exploitation of NGH also arouses high expectations of the international community. However, from the perspective of safe exploitation, it is necessary to fully understand the mechanical properties of NGH before commercial exploitation. The geological survey shows an apparent temperature gradient in the hydrate reservoir, and the hydrate saturation varies with the reservoir location. Based on the above background, we conducted mechanical experiments on hydrate-bearing samples under different temperatures and hydrate saturation conditions in this work. The data showed that the samples' strength is positively correlated with hydrate saturation and negatively correlated with temperature. The compressibility of the sample is limited by the hydrate solid in the pores. Furthermore, the samples' dilatancy is negatively correlated with temperature and positively correlated with hydrate saturation. From the perspective of experimental phenomena, temperature and hydrate saturation have a coupling effect on the mechanical properties of the samples. With increasing temperature and decreasing hydrate saturation, the stress-strain behaviors of the samples change from softening to hardening. The above experimental results can be attributed to the effect of temperature and hydrate saturation on hydrate cementation structure in pore space. Moreover, the relationship between the stress-strain behaviors and these influencing factors was established. According to the above results, the existing constitutive model of hydrate-bearing samples can be improved. The accuracy of stability analysis of hydrate reservoirs can also be improved, which provides a theoretical basis for the safe exploitation of hydrate resources.

Prestack Seismic Inversion via Nonconvex L1-2 Regularization

Using seismic data, logging information, geological interpretation data, and petrophysical data, it is possible to estimate the stratigraphic texture and elastic parameters of a study area via a seismic inversion. As such, a seismic inversion is an indispensable tool in the field of oil and gas exploration and development. However, due to unknown natural factors, seismic inversions are often ill-conditioned problems. One way to work around this unknowable information is to determine the solution to the seismic inversion using regularization methods after adding further a priori constraints. In this study, the nonconvex L1−2 regularization method is innovatively applied to the three-parameter prestack amplitude variation angle (AVA) inversion. A forward model is first derived based on the Fatti approximate formula and then low-frequency models for P impedance, S impedance, and density are established using logging and horizon data. In the Bayesian inversion framework, we derive the objective function of the prestack AVA inversion. To further improve the accuracy and stability of the inversion results, we remove the correlations between the elastic parameters that act as initial constraints in the inversion. Then, the objective function is solved by the nonconvex L1−2 regularization method. Finally, we validate our inversion method by applying it to synthetic and observational data sets. The results show that our nonconvex L1−2 regularization seismic inversion method yields results that are highly accurate, laterally continuous, and can be used to identify and locate reservoir formation boundaries. Overall, our method will be a useful tool in future work focused on predicting the location of reservoirs.

Investigating geothermal reservoir potential using numerical simulation

Egypt depends on oil and gas for electricity generation (about 90%). The remaining small percentage comes from the hydropower of the High Dam (about 8%), the wind energy, and the solar cells. Therefore, it is important to adjust this unbalanced energy mix in Egypt. The continuous scientific research is the best way to try to solve this problem by studying the feasibility of using available renewable energy sources. Among these energies is the geothermal potential energy. However, it has not been exploited as a renewable source for power generation in Egypt yet. This study aims to determine the locations of reservoirs, which have high temperature gradient that can be suitable for implementing geothermal energy projects in Egypt. The study is executed using data of deep wells that are located in different regions to investigate the technical possibility of utilizing subsurface reservoirs for geothermal power generation pilot projects. The results indicate that the best reservoirs with high temperature gradient are located in the Western Desert and around the Gulf of Suez especially at Hammam Faraun and Ras Budran fields. These two locations have recorded reservoir temperatures of 100°C and 146°C at depths of 1150 m and 3800 m, respectively. Simulation studies are conducted, and the results show that these formations can feed a power plant by 21,000 bbl/day of hot water at well head temperature ranging between 94°C and 105°C from a pilot project of two producers and one injector in Ras Budran (or four producers and two injectors in Hammam Faraun). Each pilot will be able to generate annual amount of electricity equal to 4,977 MWh through a binary cycle power plant. This proposed pilot project can be scaled up to generate additional electricity. Accordingly, application of this unfunded research recommendations can save hard currency and increase the national income.

Colonization of methicillin-resistant Staphylococcus aureus among healthcare students: an integrative review.

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a worldwide concern given its presence even in non-hospitalized healthy individuals, such as university students. To identify in the literature the prevalence of colonization by MRSA among healthcare students. Integrative review of the literature conducted in Universidade Federal do Piauí. A search for primary studies was performed in the following databases: Medical Literature Analysis and Retrieval System on-line; Cumulative Index to Nursing and Allied Health Literature; Web of Science; Scopus; and LILACS. This review included 27 studies that demonstrated MRSA infection prevalence ranging from 0.0 to 15.3% among students. The prevalence of colonization of MRSA among healthcare students is high, and the nasal cavity was cited as an important reservoir location for these microorganisms.

CO2–water–rock reaction transport via simulation study of nanoparticles-CO2 flooding and storage

Carbon dioxide (CO2) sequestration for sustainable enhanced oil recovery and reducing greenhouse gas emissions, still faces various challenges. The process performance can improve via injection of nanoparticles into CO2 (NPs-CO2). However, the migration laws of the mixed NPs-CO2 fluid in the reservoir condition, while experiencing a chemical reaction, are still unclear. In this study, a mass transfer model of NPs-CO2 nanofluid is established by combining the migration law of NPs-CO2 fluid and the micro-pore structure change of porous media under CO2–water–rock reaction conditions. Numerical simulation was performed to analyze the CO2 and reservoir formation geochemical reaction via three-dimensional stratigraphic model. Also, the influence of rock microstructure heterogeneity on migration of NPs-CO2 brine fluid and the miscibility were investigated. The physical properties of reservoir were improved as the porosity of the rock increased from 6.43% to 25.84% after 100 years. It was also noted that the average permeability (from 0.013 mD to 0.017 mD) was directly proportional to porosity at various reservoir locations. Results also indicated that due to the CO2–water–rock reaction, porosity, permeability, heterogeneity of the reservoir was generally increasing, which lead to selective migration of NPs-CO2. The local accumulation of NPs-CO2 in detached pores will slightly weaken the original oil displacement efficiency. The density difference between NPs-CO2 and formation water can promote the miscibility of NPs-CO2-brine fluid and can inhibit the acid fluid under buoyancy. The upward diffusion was moved to the cap layer and prevents the chemical reaction of the rocks, that leads to the permanent storage of greenhouse gases.