Ionosphere undergoes permanently solar flares that quickly change its properties inducing sometim... more Ionosphere undergoes permanently solar flares that quickly change its properties inducing sometime unwanted effects. These changes, or events, are known as Sudden Ionospheric Disturbances (SIDs) and the knowledge of their magnitude may be of great interest to anticipate probable damages. Currently, there does not exist any classification of these ionospheric changes based on their amplitude due to the wide variability of its responses. The only way to surmise their importance is to study them indirectly, throughout the classification of the X-ray flux intensity recorded by satellites. An attempt of classification based on their duration was proposed by the American Association of Variable Star Observers (AAVSO) but it is not very accurate because SID’s duration is measured directly from the raw signal of the Very Low Frequency (VLF) signal and/or the Low Frequency (LF) signal. The aim of this work is to investigate, through a set of simple mathematical techniques applied to VLF/LF s...
present the use of improved model building and prestack depth imaging technology and workflows th... more present the use of improved model building and prestack depth imaging technology and workflows that led to identification of multiple new opportunities in the Gulf of Mexico.
Article based on an extended abstract published in the GCAGS Transactions (see footnote reference... more Article based on an extended abstract published in the GCAGS Transactions (see footnote reference below), which is available as part of the entire 2016 GCAGS Transactions volume via the GCAGS Bookstore at the Bureau of Economic Geology (www.beg.utexas.edu) or as an individual document via AAPG Datapages, Inc. (www.datapages.com), and delivered as an oral presentation at the 66th Annual GCAGS Convention and 63rd Annual GCSSEPM Meeting in Corpus Christi, Texas, September 18–20, 2016.
SEG Technical Program Expanded Abstracts 2013, 2013
The reservoir modeling and simulation of Energy XXI's Gulf of Mexico Main Pass 61 Pod B Oil Field... more The reservoir modeling and simulation of Energy XXI's Gulf of Mexico Main Pass 61 Pod B Oil Field integrated seismic elastic properties and discontinuity analysis to improve reservoir definition, lithology distribution and to identify compartments and fluid flow pathways. The results provided key basis for improving the estimation of recoverable oil, field management decisions involving water injection and work-over completions, and the identification of un-swept potential for new drilling opportunities. Conventional reservoir modeling and simulation field studies often underutilize information contained in the seismic data. Wells sample the earth with high vertical resolution at a single location, but seismic provides highly sampled information in the intrawell space. Utilization of the intra-well seismic information leads to better definition of the reservoir and simulation results. The reservoir model integrated estimates of litho-fluid properties derived from prestack seismic inversion employing Bayesian classification methods. Reservoir boundaries and facies distributions were identified from shale and sand classification probabilities. Porosity distribution in the reservoir utilized acoustic impedance as a proxy. Seismic discontinuity analyses also provided a means to identify compartment boundaries, baffles, and lithologic barriers to fluid flow. Together, the integration of these seismic properties improved the accuracy of the geologic model and provided better understanding of reservoir production mechanisms.
Diastolic filling of hypertrophied left ventricles has frequently been observed by Doppler method... more Diastolic filling of hypertrophied left ventricles has frequently been observed by Doppler methods. We hypothesized that filling characteristics in hypertrophy vary with etiology and concurrent ischemia. For patients with hypertrophy, the left-ventricular ejection fraction was > 0.47 +/- 0.16, end-diastolic pressure was > 15 +/- 2 mm Hg, end-diastolic volume index was < 96 +/- 12 ml/m2 and left-ventricular mass index was 127 +/- 7 g/m2. Peak E (early) and peak A (late) diastolic velocities and E-wave deceleration time, respectively, were as follows (significant unless otherwise indicated): normal subjects (NS), 79 +/- 9 and 82 +/- 19 cm/s, and 151 +/- 7 ms; cardiomyopathic hypertrophy, 63 +/- 16, 83 +/- 15 (NS) and 193 +/- 63, aortic stenosis without coronary disease, 110 +/- 10, 128 +/- 12 and 158 +/- 22 (NS); aortic stenosis with coronary disease, 57 +/- 12, 86 +/- 26 (NS) and 187 +/- 39; hypertension without coronary disease, 107 +/- 9, 128 +/- 9 and 143 +/- 22 (NS); hypertension with coronary disease, 58 +/- 12, 84 +/- 26 (NS) and 189 +/- 29. Hypertrophied left ventricles filled with two diastolic Doppler patterns: a relaxation abnormality with low peak E and delayed deceleration in hypertrophic cardiomyopathy, and a compliance abnormality with tall peak E and normal deceleration in pressure overload hypertrophy. When coronary artery disease occurred with pressure overload hypertrophy, impaired relaxation was the dominant pattern. Therefore, in addition to the known physiologic influences on diastolic filling, the etiology and presence of coronary artery disease modulate the configuration of transmitral velocities into hypertrophied ventricles.
Ionosphere undergoes permanently solar flares that quickly change its properties inducing sometim... more Ionosphere undergoes permanently solar flares that quickly change its properties inducing sometime unwanted effects. These changes, or events, are known as Sudden Ionospheric Disturbances (SIDs) and the knowledge of their magnitude may be of great interest to anticipate probable damages. Currently, there does not exist any classification of these ionospheric changes based on their amplitude due to the wide variability of its responses. The only way to surmise their importance is to study them indirectly, throughout the classification of the X-ray flux intensity recorded by satellites. An attempt of classification based on their duration was proposed by the American Association of Variable Star Observers (AAVSO) but it is not very accurate because SID’s duration is measured directly from the raw signal of the Very Low Frequency (VLF) signal and/or the Low Frequency (LF) signal. The aim of this work is to investigate, through a set of simple mathematical techniques applied to VLF/LF s...
present the use of improved model building and prestack depth imaging technology and workflows th... more present the use of improved model building and prestack depth imaging technology and workflows that led to identification of multiple new opportunities in the Gulf of Mexico.
Article based on an extended abstract published in the GCAGS Transactions (see footnote reference... more Article based on an extended abstract published in the GCAGS Transactions (see footnote reference below), which is available as part of the entire 2016 GCAGS Transactions volume via the GCAGS Bookstore at the Bureau of Economic Geology (www.beg.utexas.edu) or as an individual document via AAPG Datapages, Inc. (www.datapages.com), and delivered as an oral presentation at the 66th Annual GCAGS Convention and 63rd Annual GCSSEPM Meeting in Corpus Christi, Texas, September 18–20, 2016.
SEG Technical Program Expanded Abstracts 2013, 2013
The reservoir modeling and simulation of Energy XXI's Gulf of Mexico Main Pass 61 Pod B Oil Field... more The reservoir modeling and simulation of Energy XXI's Gulf of Mexico Main Pass 61 Pod B Oil Field integrated seismic elastic properties and discontinuity analysis to improve reservoir definition, lithology distribution and to identify compartments and fluid flow pathways. The results provided key basis for improving the estimation of recoverable oil, field management decisions involving water injection and work-over completions, and the identification of un-swept potential for new drilling opportunities. Conventional reservoir modeling and simulation field studies often underutilize information contained in the seismic data. Wells sample the earth with high vertical resolution at a single location, but seismic provides highly sampled information in the intrawell space. Utilization of the intra-well seismic information leads to better definition of the reservoir and simulation results. The reservoir model integrated estimates of litho-fluid properties derived from prestack seismic inversion employing Bayesian classification methods. Reservoir boundaries and facies distributions were identified from shale and sand classification probabilities. Porosity distribution in the reservoir utilized acoustic impedance as a proxy. Seismic discontinuity analyses also provided a means to identify compartment boundaries, baffles, and lithologic barriers to fluid flow. Together, the integration of these seismic properties improved the accuracy of the geologic model and provided better understanding of reservoir production mechanisms.
Diastolic filling of hypertrophied left ventricles has frequently been observed by Doppler method... more Diastolic filling of hypertrophied left ventricles has frequently been observed by Doppler methods. We hypothesized that filling characteristics in hypertrophy vary with etiology and concurrent ischemia. For patients with hypertrophy, the left-ventricular ejection fraction was > 0.47 +/- 0.16, end-diastolic pressure was > 15 +/- 2 mm Hg, end-diastolic volume index was < 96 +/- 12 ml/m2 and left-ventricular mass index was 127 +/- 7 g/m2. Peak E (early) and peak A (late) diastolic velocities and E-wave deceleration time, respectively, were as follows (significant unless otherwise indicated): normal subjects (NS), 79 +/- 9 and 82 +/- 19 cm/s, and 151 +/- 7 ms; cardiomyopathic hypertrophy, 63 +/- 16, 83 +/- 15 (NS) and 193 +/- 63, aortic stenosis without coronary disease, 110 +/- 10, 128 +/- 12 and 158 +/- 22 (NS); aortic stenosis with coronary disease, 57 +/- 12, 86 +/- 26 (NS) and 187 +/- 39; hypertension without coronary disease, 107 +/- 9, 128 +/- 9 and 143 +/- 22 (NS); hypertension with coronary disease, 58 +/- 12, 84 +/- 26 (NS) and 189 +/- 29. Hypertrophied left ventricles filled with two diastolic Doppler patterns: a relaxation abnormality with low peak E and delayed deceleration in hypertrophic cardiomyopathy, and a compliance abnormality with tall peak E and normal deceleration in pressure overload hypertrophy. When coronary artery disease occurred with pressure overload hypertrophy, impaired relaxation was the dominant pattern. Therefore, in addition to the known physiologic influences on diastolic filling, the etiology and presence of coronary artery disease modulate the configuration of transmitral velocities into hypertrophied ventricles.
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Papers by Ahmed Ammar