A new exploration tool for subtle stratigraphic traps in the offshore Nile Delta, Egypt

2019 ◽  
Vol 26 (3) ◽  
pp. 434-447
Author(s):  
Amir M. S. Lala ◽  
Amr Talaat
Keyword(s):  
Seismic Data ◽  
Nile Delta ◽  
The Other ◽  
Class I ◽  
Class Iii ◽  
Gas Reservoir ◽  
Seismic Amplitude ◽  
Amplitude Anomaly ◽  
Exploration Tool ◽  
Gas Bearing

The offshore Nile Delta Basin is considered as one of the most promising hydrocarbon provinces in Egypt, with an excellent potential for gas and condensate reserves following future exploration. Most of the discoveries in this basin, such as the reservoirs of the Upper Miocene and the Middle–Upper Pliocene, have been enabled by the use of a direct hydrocarbon indicator (DHI), based on a class III seismic amplitude v. offset (AVO) anomaly. However, there are gas-bearing formations in the Lower Pliocene that have been successfully tested where the sand did not show any seismic amplitude anomaly in full stacks or in near- and far-offset sub-stacks. The AVO analysis of this sand reservoir is referred to as AVO class II-P. Another case of a subtle AVO class I anomaly in a Lower Pliocene gas reservoir has also been tested by three wells.These variations in AVO types push us to find a new methodology to reduce the risk of unsuccessful exploration wells, mainly using seismic data. The enhanced AVO pseudo-gradient attribute (EAP) has previously been used in other studies, mainly to highlight AVO class III anomalies. However, in the present paper, we demonstrate a workflow to identify all the principal AVO classes observed in this province. Computing the EAP attribute from our data, we find that AVO class I has negative EAP values, while the other classes have positive values. Class III and classes II and II-P may be distinguished from each other as the former yields a strong positive EAP value, whereas the latter two classes yield weak EAP responses.After determining the AVO class, we define and use a new model attribute, herein termed NM, to differentiate between gas- and water-bearing formations for each class of AVO anomaly found in this province. This new method was successfully tested in many areas in the Nile Delta Basin, where it has helped to identify subtle anomalies and thereby open the gate for further exploration activities in the area.

Bright spots, milligals, and gammas

Geophysics ◽  
1982 ◽  
Vol 47 (12) ◽  
pp. 1693-1705
Author(s):  
Alan O. Ramo ◽  
James W. Bradley
Keyword(s):  
Seismic Data ◽  
Magnetic Data ◽  
Amplitude Analysis ◽  
Seismic Amplitude ◽  
The North ◽  
Gravity And Magnetic ◽  
Amplitude Anomaly ◽  
North Edge ◽  
Gravity And Magnetic Data ◽  
Seismic Anomaly

Spatially discontinuous high‐amplitude seismic reflections were encountered in seismic data acquired in the early 1970s in northeast Louisiana and southwest Arkansas. Large acoustic impedance contrasts are known to result from gaseous hydrocarbon accumulations. However, amplitude anomalies may also result from large density and velocity contrasts which are geologically unrelated to hydrocarbon entrapment. A well drilled on the northeast Louisiana amplitude anomaly encountered 300 ft of rhyolite at a depth of 6170 ft. Subsequent gravity and total field magnetic profiles across the feature revealed the presence of 0.2 mgal and 17 gamma anomalies, respectively. The measured magnetic susceptibility of the rhyolite was 0.0035 emu and the measured density contrast was [Formula: see text]. Model studies based on the seismically determined areal extent of the anomaly and the measured thickness of rhyolite accounted for the observed gravity and magnetic anomalies. The southwest Arkansas amplitude anomaly was a sheet‐like reflection which terminated to the north and west within the survey area. Two north‐south gravity profiles exhibited a negative character over the sheet‐like reflector but did not exhibit a clear spatial correlation with the north limit of the seismic anomaly. Two north‐south magnetic profiles exhibited tenuous 4 gamma anomalies which appeared to be spatially correlated with the interpreted north edge of the seismic anomaly. A subsequent wildcat well encountered no igneous material but did penetrate 200 ft of salt at about 7500 ft. Reassessment of the gravity and magnetic data indicated that this seismic amplitude anomaly is not attributable to an intrasedimentary igneous source; it suggested a salt‐related 0.2 to 0.3 mgal minimum coextensive with the observed seismic amplitude anomaly. Present amplitude analysis technology would treat these seismic data with suspicion. However, gravity and magnetic data acquisition can provide a relatively inexpensive means for evaluation and verification of amplitude anomalies and thus should be an adjunct for land seismic exploration utilizing amplitude analysis.

scholarly journals Pulsed Electric Fields (PEF) to Mitigate Emerging Mycotoxins in Juices and Smoothies

2020 ◽  
Vol 10 (19) ◽  
pp. 6989
Author(s):  
Noelia Pallarés ◽  
Francisco J. Barba ◽  
Houda Berrada ◽  
Josefa Tolosa ◽  
Emilia Ferrer
Keyword(s):  
Electric Fields ◽  
Food Processing ◽  
Degradation Products ◽  
Pulsed Electric Fields ◽  
The Other ◽  
Class I ◽  
Class Iii ◽  
Processing Technologies ◽  
Expected Effect ◽  
Mycotoxin Reduction

The development of innovative food processing technologies has increased to answer the growing demand to supply of fresh-like products. The aim of the present study is to investigate the effect of pulsed electric fields (PEF) technology on reducing the emerging mycotoxins (enniatins (ENs) and beauvericin (BEA)) contents in juice and smoothie samples. The products of degradation obtained after PEF treatment were identified and their toxicological endpoint toxicities predicted by Pro Tox-II web. Mycotoxin reduction ranged from 43 to 70% in juices and smoothies, but in water the expected effect was lower. The acidified pH increased BEA reduction in water. The degradation products that were produced were the result of the loss of aminoacidic fragments of the original molecules, such as HyLv, Val, Ile, or Phe. Pro Tox-II server assigned a toxicity class I for enniatin B (ENB) degradation products with a predicted LD50 of 3 mg/Kgbw. The other degradation products were classified in toxicity class III and IV.

scholarly journals Dehiscence and fenestration in skeletal Class I, II, and III malocclusions assessed with cone-beam computed tomography

2011 ◽  
Vol 82 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Ahmet Yagci ◽  
İlknur Veli ◽  
Tancan Uysal ◽  
Faruk Izzet Ucar ◽  
Törün Ozer ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Null Hypothesis ◽  
Class Ii ◽  
The Other ◽  
Class I ◽  
Cone Beam ◽  
Class Iii ◽  
Skeletal Class ◽  
Dental Malocclusion

Abstract Objective: To test the null hypothesis that the presence of dehiscence and fenestration was not different among patients with skeletal Class I, II, and III malocclusions. Materials and Methods: In this retrospective study, a total of 123 cone-beam computed tomography (CBCT) images were obtained with an iCAT scanner (Imaging Sciences International, Hatfield, Pa). Patients with normal vertical patterns were classified according to dental malocclusion and ANB angle. Class I comprised 41 patients—21 girls and 20 boys (mean age, 22.4 ± 4.5 years); Class II comprised 42 patients—22 girls and 20 boys (mean age, 21.5 ± 4.2 years); and Class III comprised 40 subjects—22 girls and 18 boys (mean age, 22.1 ± 4.5 years). A total of 3444 teeth were evaluated. Analysis of variance and Tukey's test were used for statistical comparisons at the P < .05 level. Results: Statistical analysis indicated that the Class II group had a greater prevalence of fenestration than the other groups (P < .001). No difference was found in the prevalence of dehiscence among the three groups. Although fenestration had greater prevalence in the maxilla, more dehiscence was found in the mandible for all groups. In Class I, alveolar defects (dehiscence, fenestration) were matched relatively in both jaws. Furthermore, Class II and Class III subjects had more alveolar defects (41.11% and 45.02%, respectively) in the mandible. Dehiscences were seen with greater frequency in the mandibular incisors of all groups. Conclusion: The null hypothesis was rejected. Significant differences in the presence of fenestration were found among subjects with skeletal Class I, Class II, and Class III malocclusions. Fenestrations had greater prevalence in the maxilla, but more dehiscences were found in the mandible.

scholarly journals Application of Artificial Neural Network in seismic reservoir characterization: a case study from Offshore Nile Delta

2021 ◽  
Author(s):  
Adel Othman ◽  
Mohamed Fathy ◽  
Islam A. Mohamed
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Seismic Data ◽  
Reservoir Characterization ◽  
Nile Delta ◽  
Reservoir Properties ◽  
Seismic Amplitude ◽  
Inversion Methods ◽  
Amplitude Data ◽  
Seismic Reservoir

AbstractThe Prediction of the reservoir characteristics from seismic amplitude data is a main challenge. Especially in the Nile Delta Basin, where the subsurface geology is complex and the reservoirs are highly heterogeneous. Modern seismic reservoir characterization methodologies are spanning around attributes analysis, deterministic and stochastic inversion methods, Amplitude Variation with Offset (AVO) interpretations, and stack rotations. These methodologies proved good outcomes in detecting the gas sand reservoirs and quantifying the reservoir properties. However, when the pre-stack seismic data is not available, most of the AVO-related inversion methods cannot be implemented. Moreover, there is no direct link between the seismic amplitude data and most of the reservoir properties, such as hydrocarbon saturation, many assumptions are imbedded and the results are questionable. Application of Artificial Neural Network (ANN) algorithms to predict the reservoir characteristics is a new emerging trend. The main advantage of the ANN algorithm over the other seismic reservoir characterization methodologies is the ability to build nonlinear relationships between the petrophysical logs and seismic data. Hence, it can be used to predict various reservoir properties in a 3D space with a reasonable amount of accuracy. We implemented the ANN method on the Sequoia gas field, Offshore Nile Delta, to predict the reservoir petrophysical properties from the seismic amplitude data. The chosen algorithm was the Probabilistic Neural Network (PNN). One well was kept apart from the analysis and used later as blind quality control to test the results.

scholarly journals Gas-generative potential for the post-Messinian megasequence of Nile Delta Basin: a case study of Tao Field, North Sinai Concession, Egypt

2021 ◽  
Author(s):  
Mohammad Abdelfattah Sarhan
Keyword(s):  
Seismic Data ◽  
Nile Delta ◽  
Total Porosity ◽  
Effective Porosity ◽  
Low Permeability ◽  
Shale Volume ◽  
Gas Bearing ◽  
North Sinai ◽  
Very High

AbstractThe main aim of the article is to evaluate the gas potentiality for the post-Messinian megasequence in TAO Field, North Sinai Concession, offshore Nile Delta Basin. The detailed petrophysical analysis for three deviated wells in the study area (Tao-3 ST1 Well, Tao-5 STA Well and Tao-7 Well) revealed that the Pliocene Kafr El-Sheikh Formation includes eleven gas-bearing zones. These zones were named: A, B, C in Tao-3 ST1 Well and D, E, F in Tao-5 STA Well. In Tao-7 Well, the interesting zones are named G, H, I, J and K. All of these sandy intervals are relatively shallow in depth and differ in thickness between 4 and 56 m. These zones are characterized by shale volume (10%), total porosity (30–40%), effective porosity (30–35%), gas saturation (50–90%), high effective permeability to gas and low permeability to water. The seismic data displayed that listric faults and the associated rollover folds have an important role in forming structural traps for the examined gas-bearing zones in Tao Field and its surroundings. This work revealed that the success rate in discovering new gas prospects within the Pliocene–Pleistocene succession at North Sinai Concession is very high.

Hydrocarbon indicators on seismic data: Insights from poroviscoelastic modeling, amplitude, and frequency variation with offsets from the Drake Point gas field, Western Arctic Islands, Canada

2014 ◽  
Vol 2 (4) ◽  
pp. SP45-SP59
Author(s):  
Mathieu J. Duchesne ◽  
Bernard Giroux ◽  
Kezhen Hu
Keyword(s):  
Seismic Data ◽  
Low Frequency ◽  
Frequency Variation ◽  
Class Iii ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Amplitude Variation With Offset ◽  
Seismic Amplitude ◽  
Impedance Modeling ◽  
Western Arctic

The evaluation of drilling prospects is frequently based on seismic amplitude anomalies. To decipher “true” seismic prospects from “false” ones, we used poroviscoelastic (PVE) models, as opposed to other formalisms such as acoustic, elastic, viscoelastic, and poroelastic models, that provided a solution that takes into account solid and fluid attenuation mechanisms separately to model the earth’s response to the propagation of a seismic wavefield. Here, a PVE impedance modeling scheme was tested using seismic and well-log data collected on a conventional gas reservoir in the Canadian Arctic. Comparisons between seismic-to-well ties achieved using acoustic and PVE media indicated that the latter provided more realistic synthetic seismograms. Although prestack analysis revealed that the present lithological context was of class I amplitude variation with offset (AVO), the seismic signature observed was of class III AVO. Consequently, the increase in amplitude with offset was interpreted to be induced not by a lithological change (i.e., shale to sand) combined with a gas-charged interval, but rather by an increase in porosity within the sandstone reservoir itself where the gas has accumulated. Frequency variation with offset analysis using spectral decomposition, image low-frequency shadows on the far offsets attributed to the gas accumulation that were correlative with the AVO anomaly. This highlighted the importance of far offsets in anomalous amplitude and frequency events attributed to the occurrence of gas reservoirs observed on stacked data and that these events can be missed if seismic hydrocarbon indicators were solely investigated on stacked data. Finally, the method of analysis emphasized the importance of combining indirect arguments coming from the observation of prestack and stacked seismic data in the time and frequency domains for reducing risk to an acceptable level before a prospect can be drilled.

3-D Seismic Mapping and Amplitude Analysis: A Gulf of Mexico Case History

1992 ◽  
Vol 10 (4-5) ◽  
pp. 259-280 ◽  
Author(s):  
Robert L. Kidney ◽  
Ronald S. Silver ◽  
H.A. Hussein
Keyword(s):  
Gulf Of Mexico ◽  
Seismic Data ◽  
Seismic Survey ◽  
Rock Properties ◽  
Amplitude Analysis ◽  
Seismic Amplitude ◽  
Energy Company ◽  
Amplitude Anomaly ◽  
Key Steps ◽  
Seismic Anomalies

Utilization of 3-D seismic data and Direct Hydrocarbon Indicators led to the successful drilling of appraisal and development wells in the Gulf of Mexico block South Timbalier 198 (ST 198). These seismic technologies, which are routinely used by Oryx Energy Company, significantly reduced the time and cost to appraise the ST 198 discovery. Based on 2-D seismic mapping, a Pliocene Lower Buliminella (L BUL) prospect was drilled in ST 198. Although the expected reservoir was not found, an Upper Buliminella (U BUL) gas sandstone was encountered. An appraisal well of the U BUL interval confirmed this discovery. Following the drilling of these two wells, it became apparent that the structural complexities and the seismic amplitude anomalies of the area could not be adequately resolved using the 2-D seismic grid. A 3-D seismic survey was shot to delineate the discovery and evaluate the remaining potential of the South Timbalier Block 198 (ST 198). Direct Hydrocarbon Indicators (DHIs), which are seismic anomalies resulting from the hydrocarbon effect on rock properties, are generally expected from these age sands. While the 3-D survey shows a seismic amplitude anomaly associated with the U BUL reservoir, the areal extent of the seismic anomaly did not match the findings of the two wells. A DHI study was performed to determine if this inconsistency could be explained and if the amplitude anomaly could be used in the well planning. The two key steps which confirmed that this amplitude anomaly is a DHI were properly calibrating the seismic data to the well control and determining the theoretical seismic response of the gas sandstones. The DHI study along with the 3-D mapping led to the successful development of the ST 198 U BUL reservoir and to setting up a successful adjacent fault block play. Finally, 3-D mapping also identified a L BUL trap updip from the original L BUL prospect which resulted in a successful drilling effort.

The Nile Delta during the Early Dynastic and Old Kingdom periods. Preliminary remarks on the evolution of settlement landscape

2020 ◽  
pp. 13-61
Author(s):  
Natalia Małecka-Drozd
Keyword(s):  
Nile Delta ◽  
Ancient Egypt ◽  
The Other ◽  
Old Kingdom ◽  
The Third ◽  
Other Hand ◽  
Early Dynastic ◽  
Territorial Structure ◽  
Settlement Landscape ◽  
New Settlements

The 3rd millennium BC appears to be a key period of development of the historical settlement landscape in ancient Egypt. After the unification of the country, the process of disappearance of the predynastic socio-political structures and settlement patterns associated with them significantly accelerated. Old chiefdoms, along with their centres and elites, declined and vanished. On the other hand, new settlements emerging in various parts of the country were often strictly related to the central authorities and formation of the new territorial administration. Not negligible were climatic changes, which influenced the shifting of the ecumene. Although these changes were evolutionary in their nature, some important stages may be recognized. According to data obtained during surveys and excavations, there are a number of sites that were considerably impoverished and/or abandoned before and at the beginning of the Old Kingdom. On the other hand, during the Third and Fourth Dynasties some important Egyptian settlements have emerged in the sources and begun their prosperity. Architectural remains as well as written sources indicate the growing interest of the state in the hierarchy of landscape elements and territorial structure of the country.

Chemometric Analysis of Substituent Effects. VIII. Alternative Interpretation of Substituent Effects (AISE)

1995 ◽  
Vol 60 (9) ◽  
pp. 1502-1528 ◽  
Author(s):  
Oldřich Pytela
Keyword(s):  
Multiple Bond ◽  
Substituent Effects ◽  
Alternative Interpretation ◽  
Class I ◽  
Reaction Centre ◽  
Correlation Equations ◽  
Class Iii ◽  
Substituent Constant ◽  
Chemical Models ◽  
The Individual

Alternative interpretation of substituent effects (AISE) starts from the presumption that a substituent only possesses a single property described by a single substituent constant. This property is transmitted to the reaction centre by three different ways depending on the interaction type in the triad reaction centre - basic skeleton - substituent. For interpretation it is substantial whether or not the substituent has p electrons at the atom adjacent to the basic skeleton. If it has none, the substituent belongs to class I and operates only by its basic effect described by the mentioned single substituent constant. Substituents of class II possess a free electron pair at the atom adjacent to the basic skeleton, and those of class III have a multiple bond between the first and the second atoms which is polarized in the direction from the basic skeleton. Substituent effects in class I are described by a substituent constant identical with σI constant. Substituents in classes II and III show additional effects proportional to the same constant. Hence, a separate treatment of substituent effects in the individual classes provides three straight lines intersecting in a common point. Mathematically, the description of substituent effects in this approach is expressed by a family of lines with a single explaining variable. The point of intersection, which is referred to as the iso-effect point, is not identical with the classic standard substituent - hydrogen - but is near to CN substituent. The approach given has the advantage of adopting a single substituent constant whose scale can be adjusted relatively precisely. Its drawback (like in the case of the correlation equations derived from the principle of separation of substituent effects) lies in a more extensive set of substituents needed for a correlation. The AISE principle has been applied to 318 series of experimental data describing effects of 32 substituents in a large variety of chemical models (aliphatic, alicyclic, aromatic, heteroaromatic, with or without direct conjugation between reaction centre and substituent) in both chemical reactions and equilibria. A comparison with two other correlation relations with two and three substituent constants for interpretation of substituent effects based on the principle of separation of the individual substituent effects showed that the closeness of AISE based correlations is comparable with that of the correlation equations currently used. It was somewhat less successful in the models with direct conjugation between reaction centre and substituent but the AISE principle can be used even in these cases.

scholarly journals Environmental Cadmium Exposure and Dental Indices in Orthodontic Patients

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 413
Author(s):  
Hui-Ling Chen ◽  
Jason Chen-Chieh Fang ◽  
Chia-Jung Chang ◽  
Ti-Feng Wu ◽  
I-Kuan Wang ◽  
...  
Keyword(s):  
Cadmium Concentration ◽  
Class Ii ◽  
Cadmium Exposure ◽  
Class I ◽  
P Value ◽  
Tooth Decay ◽  
Class Iii ◽  
Orthodontic Patients ◽  
Urine Cadmium ◽  
The Mean

Background. Previous studies have shown that environmental cadmium exposure could disrupt salivary gland function and is associated with dental caries and reduced bone density. Therefore, this cross-sectional study attempted to determine whether tooth decay with tooth loss following cadmium exposure is associated with some dental or skeletal traits such as malocclusions, sagittal skeletal pattern, and tooth decay. Methods. Between August 2019 and June 2020, 60 orthodontic patients with no history of previous orthodontics, functional appliances, or surgical treatment were examined. The patients were stratified into two groups according to their urine cadmium concentrations: high (>1.06 µg/g creatinine, n = 28) or low (<1.06 µg/g creatinine, n = 32). Results. The patients were 25.07 ± 4.33 years old, and most were female (female/male: 51/9 or 85%). The skeletal relationship was mainly Class I (48.3%), followed by Class II (35.0%) and Class III (16.7%). Class I molar relationships were found in 46.7% of these patients, Class II molar relationships were found in 15%, and Class III molar relationships were found in 38.3%. The mean decayed, missing, and filled surface (DMFS) score was 8.05 ± 5.54, including 2.03 ± 3.11 for the decayed index, 0.58 ± 1.17 for the missing index, and 5.52 ± 3.92 for the filled index. The mean index of complexity outcome and need (ICON) score was 53.35 ± 9.01. The facial patterns of these patients were within the average low margin (26.65 ± 5.53 for Frankfort–mandibular plane angle (FMA)). There were no significant differences in the above-mentioned dental indices between patients with high urine cadmium concentrations and those with low urine cadmium concentrations. Patients were further stratified into low (<27, n = 34), average (27–34, n = 23), and high (>34, n = 3) FMA groups. There were no statistically significant differences in the urine cadmium concentration among the three groups. Nevertheless, a marginally significant p-value of 0.05 for urine cadmium concentration was noted between patients with low FMA and patients with high FMA. Conclusion. This analysis found no association between environmental cadmium exposure and dental indices in our orthodontic patients.

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