Lithology-dependent seismic anisotropic amplitude variation with offset correction in transversely isotropic media

Analysis of amplitude variation with offset is an essential step for reservoir characterization. For an accurate reservoir characterization, the amplitude obtained with an isotropic assumption of the reservoir must be corrected for the anisotropic effects. The objective is seismic anisotropic amplitude correction in an effective medium, and, to this end, values and signs of anisotropic parameter differences (Δδ and Δε) across the reflection interfaces are needed. These parameters can be identified by seismic and well log data. A new technique for anisotropic amplitude correction was developed to modify amplitude changes in seismic data in transversely isotropic media with a vertical axis of symmetry. The results show that characteristics of pre-stack seismic data, that is, amplitude variation with offset gradient, can be potentially related to the sign of anisotropic parameter differences (Δδ and Δε) between two layers of the reflection boundary. The proposed methodology is designed to attain a proper fit between modelled and observed amplitude variation with offset responses, after anisotropic correction, for all possible lithofacies at the reservoir boundary. We first estimate anisotropic parameters, that is, δ and ε, away from the wells through Backus averaging of elastic properties resulted from the first pass of isotropic pre-stack seismic inversion, on input data with no amplitude correction. Next, we estimate the anisotropic parameter differences at reflection interfaces (values and signs of Δδ and Δε). We then generate seismic angle gather data after anisotropic amplitude correction using Rüger's equation for the P-P reflection coefficient. The second pass of isotropic pre-stack seismic inversion is then performed on the amplitude-corrected data, and elastic properties are estimated. Final outcome demonstrates how introduced methodology helps to reduce the uncertainty of elastic property prediction. Pre-stack seismic inversion on amplitude-corrected seismic data results in more accurate elastic property prediction than what can be obtained from non-corrected data. Moreover, a new anisotropy attribute (ν) is presented for improvement of lithology identification.     

A Genetic Programming–Based Model for Colloid Retention in Fractures

Understanding the behavior of colloids in groundwater is critical as some are pathogenic while others may facilitate or inhibit the transport of dissolved contaminants. Colloid behavior in saturated fractured aquifers is governed by the physical and chemical properties of the groundwater-particle-fracture system. The interaction between these properties is nonlinear, and there is a need for a mathematical model describing the relationship between them to advance the mechanistic understanding of colloid transport in fractures and facilitate modeling in fractured environments. This paper coupled genetic programming and linear regression within a multigene genetic programming framework to develop a robust mathematical model describing the relationship between colloid retention in fractures and the physical and chemical parameters that describe the system. The data employed for model development and validation were collected from a series of 75 laboratory-scale colloid tracer experiments conducted under a range of conditions in three laboratory-induced discrete dolomite fractures and their epoxy replicas. The model sufficiently reproduced the observed data with coefficients of determination (R²) of 0.92 and 0.80 for model development and validation, respectively. A cross-validation demonstrated the model generality to 86% of the observed data. A variance-based global sensitivity analysis confirmed that attachment is the primary retention mechanism in the systems employed in this work. The model developed in this study provides a tool describing colloid retention in factures, which furthers the understanding of groundwater-particle-fracture system conditions contributing to the retention of colloids and can aid in the design of groundwater remediation strategies and development of groundwater management plans.     

Toxicity of organophosphorus pesticide sumithion on larval stages of stinging catfish <Emphasis Type="Italic">Heteropneustes fossilis</Emphasis>

Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations (150 and 250 μg/L) of sumithion with one control in three replicates of each. Larvae samples were collected at 20- and 24-h intervals followed by observation under a digital microscope. Exposures of stinging catfish larvae to sumithion produced deformities including irregular head shape, lordosis, yolk sac edema, body arcuation, tissue ulceration, etc. The mortality rates of larvae were significantly increased in response to increase in sumithion concentrations. Furthermore, around 30% of the total adult stinging catfish reared in sumithiontreated aquaculture ponds were found to be deformed permanently. These findings highlight that exposure of stinging catfish to sumithion at the critical and sensitive stages in their life cycle may significantly reduce the number of returning adults. Therefore, the use of sumithion for crop protection needs to be considered carefully and alternatives to sumithion should to be developed for controlling aquatic insects in aqua-ponds during larval rearing.     

Biostratigraphy and seismic data analysis to detect the sequence stratigraphic depositional environment of the Miocene succession: Gulf of Suez (Egypt)

This work comprises a study of the sequence stratigraphy, seismic-facies analysis, biostratigraphy and depositional environments of the northern part of the Gulf of Suez, Egypt, using a set of 24 3D seismic profiles, composite logs and sonic logs from ten wells. The syn-rift formations in the studied ten wells are described lithologically and interpreted based on investigating two seismic profiles. Biostratigraphically, the Miocene fossils are identified to correlate the five planktonic foraminiferal biozones in the examined boreholes (RB-A1, RB-B1, RB-B3, EE85-2 and RB-C1). The sequence stratigraphic analysis suggests that the Miocene succession can be subdivided into two major third order depositional sequences (S1 and S2) separated by the three major sequence boundaries (DSB1, DSB2 and DSB3).     

RETRACTED ARTICLE: Physiological comparative study of six wild grapevine (<Emphasis Type="Italic">Vitis sylvestris</Emphasis>) accession responses to salinity

Salinity problems for vineyards are in concerns, especially in coastal areas where several aquifers are reported to be affected by seawater intrusion and agricultural contamination. Saline irrigation affects growth, yield, and fruit quality of grapevines. Exploring germplasm base through wild ancestors of the target species is a novel adopted strategy to increase crop tolerance to irrigation with saline water. The effects of salt on growth, organic and inorganic solute accumulations, and chlorophyll florescence were studied on 3-month-old plants of six Tunisian wild grapevines with the objective to identify salt tolerance mechanisms and select tolerant genotypes. Potted plants were grown under controlled conditions and irrigated for 14 days with 0, 100, and 150 mM NaCl nutrient solution. Parameters analyzed were related to growth, water relations, mineral nutrition, and chlorophyll fluorescence. Several processes are operating either at the whole plant or at cell level. They appear to be involved in salt tolerance of wild grapevines and are more efficient in tolerant accessions. Salt adversely affects plant growth and plant nutrition. Reductions of shoot growth rate (relative growth rate, day^?1) reached 49% of control since 100 mM NaCl. They were assigned to stomatal closure and alteration of potassium nutrition and photochemistry. There were significant differences (P < 0.05) within accessions, Tebaba was the most tolerant and Houamdia the most sensitive, while the others were intermediate.     

Electrical and electromagnetic surveys to locate possible causes of water seepage to ground surface at a quarry open pit near Helwan city,Egypt

Water seepage to ground surface at a limestone quarry located at Wadi Garawy about 20 km south-east of Helwan city in Egypt posed a real threat to the mining activity at the quarry. The quarry area is known to be very dry for decades and away from water utilities and infrastructures that may cause water leaks to the quarry. Geophysical investigation including 1D Vertical Electrical Sounding (VES), 2D Electrical Resistivity Tomography (ERT) and 1D Transient Electromagnetic (TEM) surveys were conducted to characterize the rock sequence and locate what could be a possible source of water seepage to the quarry. The resistivity profiles generated from the VES and TEM surveys mapped the rock units in the area down to depths exceeded 100 m. The ERT profiles acquired from the quarrying zone close to the water seepage spot have imaged the top of groundwater level at few meters below the ground surface at the quarry open pit. The spot of groundwater seepage seemed to occur at an area of limestone dissolution that were filled by finer sediments. The finer sediments acted as a hydrological conduit that allowed an upward seepage of groundwater to ground surface under the capillary action effect.     

Impact of rock-water interactions and recharge on water resources quality of the Agadir-Essaouira basin,southwestern Morocco

The Agadir-Essaouira area in the occidental High Atlas Mountains of Morocco is characterized by a semi-arid climate. The scarcity and quality of water resources, exacerbated by long drought periods, constitute a major problem for a sustainable development of this region. Groundwater resources of carbonate units within Jurassic and Cretaceous aquifers are requested for drinking and irrigation purposes. In this study, we collected 84 samples from wells, boreholes, springs, and rivers. Hydrochemical and isotopic data were used to examine the mineralization and origin of water, which control groundwater quality. The chemical composition of water seems to be controlled by water-rock interactions, such as dissolution of carbonates (calcite and dolomite), weathering of gypsum, as well as ion exchange processes, which explain the observed variability. Stable isotopes results show that groundwater from the mainly marly Cretaceous aquifer are submitted to an evaporation effect, while samples from the chiefly calcareous Jurassic aquifer indicate a meteoric origin, due to a rapid infiltration of recharge runoff through the karstic outcrops. The low values of δ¹⁸O and δ²H suggest a local recharge from areas with elevations ranging from 400 to 1200 m for the Cretaceous aquifer and from 800 to 1500 m for the Jurassic units.     

Status of sedimentation in King Talal Dam,case study from Jordan

This paper focuses on characterizing the current status of physical and chemical characteristics of King Talal Dam (KTD) sediments. The quality of sediments was investigated based on several international sediment quality guidelines. The volume of sediment and sedimentation rate in (KTD) was also estimated. Five types of granulometric textural facies were observed for the sediments of KTD reservoir bed, with an average grain size distribution of gravel (1.38%), sand (32.38%), silt (32.35%) and clay (32.38%). The fraction of <63 micron showed that the total mean size was 8.0 micron. Other sediment parameters in KTD were 7.0% for total organic matter (TOM), 7.3 for pH, 35.9% for CaCO₃ and 100.5 meq/100 g for cation exchange capacity, with dominant mineralogical constituents of quartz, calcite, dolomite, clay minerals and minor feldspar. The total concentrations of F, Cl, NO₂, NO₃, PO₄ and SO₄ in sediment samples were lower inward for KTD. The vast majority of trace metals in sediments were generally within the standard limits recommended for soils. TOM and grain size of sediment are major factors governing the trace metal concentrations. The calculated geoaccumulation index (I _geo) and enrichment factor of metals in bottom sediments showed that the metals were in the following order: Cd > Pb > Zn > Co > Cr > Ni > Fe > Cu > Sr > Mn and Cd > Zn > Pb > Co > Cr > Ni > Cu > Sr > Mn, respectively. Based on the sonic survey of KTD reservoir, the annual sedimentation rate was about 0.4061 MCM/year, in which about 18.66% of the reservoir initial storage capacity was lost to sediments and a projected lifespan of about 198 years.     

Studying the impacts of groundwater evolution on the environment,west Qena city,Egypt

The current research has been conducted to evaluate groundwater aquifers qualitatively in the area located in the Western side of Qena city. The Quaternary aquifer represents the main groundwater source in the study area. It exists under unconfined to semiconfined conditions at depths varying between 4 m due North and 80 m in the South. The chemical analyses of the groundwater samples indicate that 77% of the total samples are fresh and 20% are brackish, while only 3% are saline. In addition, the iso-salinity contour map indicates that the salinity increases towards the central and northern parts of the study area. The total and permanent hardness increase as water salinity increases and vice versa in case of temporary hardness in the groundwater samples. The chemical water types and the ion ratios indicate meteoric origin of groundwater as well as the dissolution of terrestrial and marine salts. The contribution of recent recharge from the River Nile to a few groundwater wells in the study area varies from low to high. In addition, the most recharge sources are from the precipitation. Nitrate concentrations in groundwater increase towards the central and Northern areas significantly elevated in response to increasing anthropogenic land uses. Much of the solutes and physicochemical parameters in these waters are under the undesirable limits of World Health Organization (WHO) for drinking purpose, and a plot of sodium adsorption ratio versus EC shows that about 23% of the groundwater samples are good water quality, about 45% of groundwater samples are moderate quality, and 23% of the groundwater samples are intermediate water class, while the rest of samples (9%) are out of the range.