الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Sayun-Masila basin is one of the most important oil productive basin in the eastern part of the Republic of Yemen. The study area occupies the central part of the Sayun-Masila basin which are located at Hadramawt region, lies between latitudes 15о 10’ and 15о 55’ N., and longitudes 48о 58’ and 49о 20’ E.The ground magnetic, gravity, twentyfive 2D seismic lines and with geologic information from 26 deep oil wells, drilled in Sunah, Cammal, Haijah, Tawila, Hemiar, and Haru oil fields, were mainly used to identify the subsurface features affecting the study area that controls its hydrocarbon potentials as well as its production.Different techniques of processing and interpretation of the magnetic and gravity data were applied including frequency domain filtering, spectral analysis, analytical signal and 3D Euler deconvolution techniques. The results showed that the depth of the basement surface in the study area ranges from 1.85 Km to 4.1 Km. The shallower depth agree well with the drill holes data which reached the higher structures and the deeper depth represents basins and subbasins structure. The interpreted normal slip faults were deduced from the gravity and magnetic, geologic sections and showed that, the study area is affected by three major structural trends; NW – SE, NNE – SSW and NEE – SWW.
The integrated basement relief map which constructed based on the results of gravity and magnetic data interpretation as well as wells data showed the shallower depths in the central and western part of the study area (between 200 & -800m from sea level) while the deeper basement exist in the southern and northern parts (between 1600 - 2500m subsea level). Also the major interpreted normal faults and shears which are dissecting the basement forming basins, subbasins and uplifted basement blocks, are clearly identified and traced out with their sense of displacements.
Time-to-depth relationships (TDR) and synthetic seismograms were derived from available check shot data for twelve wells which had been used for time depth relation to be applied for all wells. Log data from the wells in the area under study and the 2D seismic lines were used for the synthetic-to- seismic reflector.
Synthetic seismograms were used to establish the geological features in the subsurface that detected by converting the sonic and density log data into reflection coefficient series.In addition the previously interpreted seismic sections are tied well with the uninterpreted seismic section to define the formation tops and then extend the interpretation all over the study area.Twentyfive seismic lines were interpreted to determine the subsurface entrapping styles throughout picking the TWT for six formations (Basement, Saar, Qishn Carbonate, Qishn Clastic, Harshiat and Fartaq). Folds, faults and unconformities which affecting these formations were traced and plotted on the TWT maps of the formations as reflectors.Six TWT reflection maps on the tops Basement, Saar, Qishn Carbonate, Qishn Clastic, Harshiyat and Fartaq rock units were represented and enhanced the structural frame work of each formation.he average velocities on the formation tops are calculated and used for time-to-depth relationships (TDR). Six average velocity gradient maps on the tops of the Basement, Saar, Qishn Carbonate, Qishn Clastic, Harshiyat and Fartaq rock units were constructed and used for TDR.Depth conversion were done for the interpreted horizons using results velocity modelling from check shot data. The depth maps illustrated major faults lines with different dip directions. Some of these faults start from the Basement to the Fartaq Formation and other faults are limited for the younger formations. The maps show a series of normal faults, grabens, and horsts.