الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The objectives of the thesis are; firstly determine the regional and field scale structural features as well as the stratigraphic correlation of the different reservoir levels. Secondly, to use different seismic attributes to enhance structural interpretation and reservoir extension and distribution delineation in the field. Thirdly, identify the AVO response and model the reservoir AVO behavior. Finally integrate AVO modeling and post-stack seismic inversion of reservoir rocks to emphasize discrimination of lithology and pore fluids. This ultimately has been done for exploring the remaining potentials of hydrocarbon in the area, estimating hydrocarbon reserves of proposed prospects, and generating a prospectivity portfolio in the study area.
The first chapter gives a general introduction of the study area. In addition, it discusses motivation of the research objectives and gives an overview of Denise field and Nile Delta Exploration history.
Chapter two describes the structure, tectonic and geological frameworks of Nile Delta and Eastern Mediterranean. It also describes briefly the geological evolution, stratigraphy and petroleum system in the study area, as well as the available geological data used during the study.
A brief theoretical background of Seismic attributes has been given in chapter three. Different theories and classifications are described under different subheadings following an order of the workflow. Practical applications of seismic attributes in seismic interpretation workflow as an aid tool for reservoir detection and delineation are then outlined.
Chapter four includes the theory and application of AVO using the data available. AVO models, classes and results are highlighted with practical focus on the possible applied methodologies according to the data available.
Chapter five introduces the basics of seismic inversion and forward modelling concepts. It also includes the data handling needed for performing
seismic inversion, as well as the different techniques and approaches of post stack and pre-stack seismic inversion. Application of post stack seismic inversion then followed the theory to highlight the benefits of post stack seismic inversion in reservoir characterization. Post-stack seismic inversion is carried out with special emphasis on results and discussion for the prospects and leads.
Chapter six reviews reserve volumetric calculation basics and estimation of volumes for prospects and leads.
Finally, a summary of the entire research and major conclusions are given in chapter seven.
Two synthetic sesimograms were created for Denise-1 and Denise south-1 wells. These synthetic seismograms were the basis for linking seismic reflectors in time with the surface picks in wells in depth domain. It also confirmed the reverse polarity of the seismic data used in this study.
By integrating conventional seismic interpretation techniques and seismic attributes, time surfaces were created for upper Denise and lower Denise reservoirs, as well as for top for seafloor, top upper Pliocene sequence, and top Rosetta Formation. Seismic attributes revealed detailed structural information and increased the accuracy of horizon interpretation process. Fault likelihood attribute was extracted along the two reservoirs and increased the structure interpretation details in terms of fault positioning and minor faults interpretation accuracy.
Extracting several stratigraphic seismic attributes for the two reservoirs highlighted the area extension of these reservoirs and highlighted the possible areas of prospects in the study area. Amplitude maps, reflection strength maps and sweetness maps of the two reservoirs resulted in several prospects and leads delineation. Five prospects were identified for upper
Denise sand and two leads were proposed for lower Denise sand. However, these prospects need more validation through advanced techniques of AVO and seismic inversion.
AVO analysis was performed for assessing the AVO classes of the proved reservoirs already drilled. Amplitude versus offset and intercept versus gradient crossplots have been utilized for this step. Upper Denise sand in Denise-1 well showed a class III AVO with a clear separation between gas bearing and water bearing sands. The prospects of UDS also showed the same AVO behavior of class III. In Denise south-1 well, lower Denise sand also has showed a class III AVO but with an indication of facies that are different from UDS. However, the two leads of LDS showed a class I AVO. These prospects and leads were furtherly investigated and represented through different AVO attributes such as AVO product, reflection coefficient difference, and scaled Poisson ratio.
Another validation technique used in this study is the seismic inversion. Post stack seismic inversion results of acoustic impedance have strengthen the confidence in seismic interpretation, seismic attributes, and AVO work. Model based inversion was carried out and acoustic impedance maps were extracted along the two reservoirs to increase the possibility of success and reveal higher accuracy prospects mapping and delineation.
Finally, hydrocarbon reserve estimation of the proposed prospects and leads were calculated using petrophysical parameters of the existing wells to understand the volume of remaining potentiality in the area. Volumetric reserve estimation method has been utilized to reveal that about 4.8BSCM of gas reserve is still possible to attain from UDS prospects, and more than 3.2 BSCM for the two leads of LDS. Total reserve is estimated to be 8 BSCM.
The results obtained from this study prove that integrating conventional seismic interpretation with more advance techniques such as seismic attributes, AVO, and seismic inversion is a powerful process in reservoir delineation and characterization. Integrating the results of such techniques helped in detecting the gas reservoirs in the field. It is recommended to use such workflow of different techniques integration in the field for this and other areas Nile Delta and Mediterranean.