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This study discusses the challenges in logging the evaluation of low-resistivity oil reservoirs, especially the difficult problems involving their saturation calculation. A correction method for equivalent water conductivity is proposed, given the high conductivity caused by small amounts of water distributed in a network within the low-resistivity reservoir, which mimics the effects of high water saturation. This approach significantly improves the accuracy of hydrocarbon saturation calculations in these low-resistivity reservoirs. The corrected hydrocarbon saturation values highly matched the porosity and are consistent with experimental results. This study also establishes a discrimination process to determine whether corrections are required, verifying the effectiveness and accuracy of the method through an application example.

Changes in land use can cause degradation of soil physical quality with negative effects on the environment and agricultural production. The effects of different land uses on soil physical-hydric attributes were studied in the Renato River and Caiabi River watersheds in the southern Brazilian Amazon. Three conditions of land use were evaluated: native forest, crops, and pasture in the headwater, middle, and mouth of each watershed. Particle size, particle density, bulk density, total porosity, macroporosity, microporosity, water contents at field capacity and permanent wilting point, and available water capacity in soil were evaluated in three soil layers down to 0.4 m. Data collected were subjected to the Kruskal–Wallis nonparametric test and Pearson’s correlations. Multivariate analyses were also performed using the principal component method. In the Renato watershed, in comparison with native forest, conventional management of pasture and crops caused soil physical degradation, increasing soil density in the surface layer and reducing macroporosity and total porosity. In the Caiabi watershed, converting native forest areas into pasture and crops altered water quality, influencing the water dynamics in the soil, by reducing soil water conductivity. Soil attributes varied by watershed, with texture variations between the headwater and mouth, indicating that changes in soil properties result from both management and the granulometric composition of the soil in different regions of the same watershed. Adoption of crop and pasture conservation practices can improve soil physical attributes in regions bordering agricultural areas in the southern Amazon.

Purpose Over the past three decades, open-pit mining has been expanding in arid and semi-arid areas of China.Open-pit mining profoundly changes the soil environment and has a profound impact on the circulation of soil water in the aeration zone.Therefore, this research explores the impacts of open-pit coal mining on soil moisture processes in the semi-arid grasslands of Eastern Inner Mongolia Autonomous Region, China. Materials and methods Soil samples were collected from depths of 0–500 cm at Shengli No. 1 open-pit mine’s inner dump and a nearby natural grassland. These soil samples were analyzed for stable isotope characteristics ( δ 2 H , δ 18 O ) and moisture content. Collection of underground water samples inside and outside the mining area for conductivity analysis. Results and discussion Soil evaporation loss in the mine’s inner dump was significantly higher than in the grassland, with rates of 22.26% for δ 18 O and 6.61% for δ 2 H . The limiting depth of soil evaporation at the mine was found to be 260 cm, compared to 200 cm in the grassland. The increased underground water conductivity in the mine area was linked to heightened soil evaporation loss. Isotopic profiling of the soil indicated that the open-pit mining led to deeper preferential flow infiltration during heavy precipitation, reaching 280 cm in the mine area versus 220 cm in the grassland. Conclusions The surface soil moisture content (SMC) increased due to mining activities intensified water-heat exchanges with the atmosphere, leading to more frequent and severe wet-dry cycles. This study provides a comprehensive understanding of open-pit mining’s impact on SMC, evaporation, and infiltration in semi-arid areas, offering critical insights for ecological reclamation and sustainable mine construction.

An experiment was carried out to study the effect of soil organic carbon (SOC) and soil texture on the distance of the wetting front, cumulative water infiltration (I), infiltration rate (IR), saturated water conductivity (Ks), and water holding capacity (WHC). Three levels ( 0, 10, 20, and 30 g OC kg-1 ) from organic carbon (OC) were mixed with different soil materials sandy, loam, and clay texture soils. Field capacity (FC) and permanent wilting point (PWP) were estimated. Soil materials were placed in transparent plastic columns(12 cm soil column ), and water infiltration(I) was measured as a function of time, the distance of the wetting front and Ks. Results showed that advance wetting front as a function of time for soil column was 6 minutes and with no differences between OC levels for sandy soils, while it ranged between 90 minutes (0% OC) - 130 minutes (3% OC) for loam soils, and between 470 minutes (0 %OC) and 590 minutes (1%OC) for clay soils, at the same time cumulative water infiltration(I) increases at the beginning of infiltration and decreases with time and levels of OC. The highest infiltration values were in sandy soils, giving data of 0.05 and 0.12 cm min-1, with no significant differences with OC rates. IR values decreased when OC increased in loam soils, and IR increased exponentially in clay soils with increasing OC levels. The values of Ks decrease with increasing OC for sandy and loam soils, and increase when OC increases above 3% for clay soils. FC and WP values were increased for sandy, loam and clay soils when OC was increased. The AW values decreased for both sandy and clay soils compared to loam soils. It can be concluded that AW can be estimated from FC values regardless of texture and OC by the linear function: AW=0.51(FC)+0.005.

In this study, we explore the possibility of reusing end-of-life seawater reverse osmosis (RO) membranes to treat brackish water and industrial effluent. Prior to cleaning the end-of-life RO membranes, we conducted several autopsies in order to assess the extent of degradation. Based on these results, three cleaning protocols were tested and Ultrasil10 and/or chlorine solution were selected for further investigation. The cleaning capacity of the chlorine treatment at 4000 ppm.h was tested but proved inefficient as it leads to a denser cake and a significant decrease in hydraulic permeability. Therefore, we recommend commencing chemical cleaning with Ultrasil10 to remove foulants, thereby reconditioning the end-of-life RO membranes to meet nanofiltration membrane specifications. The cleaned end-of-life RO membranes exhibited enhanced hydraulic permeability (1.97 L·h⁻¹·m⁻²·bar⁻¹) and achieved a salt rejection of 85% for brackish water (6 g/L NaCl). With a molecular weight cutoff of 86 Da, these membranes effectively reduced brackish water conductivity to below 1000 µS/cm at 10 bars, complying with Tunisian drinking water standards (300–2500 µS/cm). Additionally, they demonstrated high efficiency in treating industrial effluents, achieving turbidity levels below 2 NTU and conductivity of 180 µS/cm. Operating at lower pressures, these membranes provided cost-effective, sustainable solutions and performed comparably to commercial new NF membranes, validating their potential for reuse in brackish water and wastewater treatment applications.

The quantitative determination of liquid water content and salinity in soils is crucial for the preservation of hydrological environments and engineering infrastructures, especially in frozen regions. Electrical conductivity, as a fundamental physical parameter in electrical and electromagnetic non‐destructive techniques, varies significantly with the physical and chemical properties, such as pore water conductivity, salinity, water saturation, and temperature. In this study, accounting for pore size and tortuous length following fractal distributions, we develop a new capillary bundle model for variation of electrical conductivity as a function of temperature in broad water saturation and salinity ranges. In this new model, we consider the contributions of bulk and surface conductivities to the total electrical conductivity. To test this model, a series of laboratory experiments were carried out for different initial water saturations and salinities using an electrical resistance apparatus and a nuclear magnetic resonance method. The experimental results show that unfrozen water saturation and ionic concentration affect the electrical conductivity of unsaturated frozen soils. Furthermore, the proposed model is capable of fitting the main trends of the experimental data from the literature and acquired in this study in unfrozen‐frozen conditions for different water contents. Relying on the proposed model, we also determine the expression of the apparent formation factor, which is significantly sensitive to porosity, water saturation, and temperature. The predicted values of the apparent formation factor also agree very well with the experimental data. This new capillary bundle model provides a new perspective in interpreting electrical monitoring to easily deduce changes in key variables in the cryosphere such as liquid water content and moisture gradients. Key Points We propose a new capillary bundle model that accounts for fractal pore size and tortuosity distributions in the electrical conductivity of frozen porous media Electrical conductivity changes with decreasing temperature in two stages: a gradual decrease followed by a sharp drop below the freezing temperature This new model correctly reproduces experimental data in a wide temperature, water saturation, and salinity ranges

Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz.

Fractured rocks play a crucial role in myriad natural and engineered systems, including Earth's critical zone, oil/gas/geothermal reservoirs, and geological CO2/H2/waste storage systems. While complex electrical conductivity is extensively used to estimate the pore and grain sizes of conventional porous rocks and soils, it is rarely used to predict the aperture size of fractured rocks and this remains poorly understood. Here, integrating theory, simulations, and experiments, we show that under external fields, fractured rocks follow the fracture‐and‐matrix coupling to make the bulk complex conductivity non‐linear with respect to water conductivity. We find that the relaxation time and quadrature conductivity for porous media do not apply to fractured rocks, but, instead, reasonably accurate predictions of aperture size can be made based on the true formation factor. This study unravels the fundamental mechanism governing conduction and polarization of fractured rocks and paves the way for the non‐invasive investigation of global fractured rocks.

Increasing concentrations of dissolved ions in freshwater ecosystems often stem from anthropogenic sources and have been implicated in the decline of sensitive aquatic organisms. Eastern hellbenders ( Cryptobranchus a. alleganiensis ) are fully aquatic salamanders that are experiencing range-wide declines and increased conductivity has been suggested as a cause. Declining populations are skewed towards older age classes, indicating a lack of successful reproduction (i.e., population recruitment). Therefore, insights into mechanisms that may cause mortality in early life stages are of great value to hellbender conservation. We conducted an experimental study to evaluate the effects of increased conductivity on the survival and development of hellbender eggs and newly hatched larvae. Wild-collected eggs were incubated across a range of conductivities (100, 300, 600, 1,000 µS/cm). We used two types of salt, aquarium salt and rock salt, to manipulate conductivity during and after hatching. Overall mortality rates were low (< 0.07) across all treatments, but highest in the 1,000 µS/cm treatments (0.14). There was no difference in mortality between aquarium salt and rock salt treatments, however the rock salt treatment stimulated earlier hatching times. Larvae reared in the 1,000 µS/cm treatments had shorter snout-vent length (SVLs) (mean = 25.44 mm) than those reared at 300 µS/cm (mean = 26.95 mm) and marginally smaller head and mid-section width than individuals reared in the 100 µS/cm treatments. Our study suggests that higher conductivity has limited effects on egg and larval survival and development, and that water conductivity alone may be a suboptimal metric relating the persistence of hellbender populations to water quality. In addition, the type of salt affected hatching rates and timing, thus evaluating the composition and concentration of various ions leading to elevated conductivity is essential to understanding how degraded water quality may affect early life stages of this imperiled amphibian.

Groundwater-fed helocrene springs constitute hydrologically heterogeneous environment, vulnerable to human and climate-induced changes. Using quantitative samples of clitellate assemblages, we investigated whether hydrologically stable nearby streams can serve as refugia for species inhabiting helocrenes, prone to seasonal desiccation. As water conductivity constitutes the main environmental gradient of helocrene springs, we categorized them as low or high-conductivity sites and compared their assemblage diversity. We hypothesized that the spring–stream association can change along this gradient, expecting assemblage homogenization is promoted by high tufa precipitation, creating differences with tufa-free nearby streams. Contrary to this prediction, the assemblages of low-conductivity helocrenes were more homogeneous, being also significantly different from those in the streams. This result is related to the apparently more favorable tufa-free substrate at low-conductivity fens, as shown by the high taxa richness and the number of indicator species. Contrary to the other invertebrates, the clitellates differed between spring fens and streams only under acidic conditions. It seems that small adjacent streams can only serve as potential refugia for spring fen biota at sites with high conductivity, while at sites with low conductivity, clitellate assemblages differ more from those in adjacent streams and thus are more susceptible to disturbance.