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Abstract The present work deals with a combined interpretation of the well logging data and the subsurface evaluation data, to help in the manifestation of the effect of tectonic setting on the reservoirs characteristics of Lower Cretaceous of the area under study comprising the Northern Sinai. The main results and the most important conclusions revealed from such study can be summarized as follows: Geology:- The subsurface sequence penetrated consists of a sedimentary section ranging in age from Cambrian .to Recent. The encountered sections of the Lower Cretaceous in these wells were subjected to formation evaluation process and complete subsurface evaluation. The Lower Cretaceous is composed of sandstone, shale and limestone. The environmental conditions are the shallow platform. The Lower Cretaceous was penetrated in all drilled wells in the study area. The maximum thickness at NS 21-1 well (31OS ft) and the minimum thickness at Tineh-2 well (449ft). Analytical well logging analysis: - A comprehensive formation evaluation was carried out for the Lower Cretaceous section encountered in the selected seven wells in the area under study. The procedure followed in the present work included the determination of the fluid resistivities (Rm, Rmr and Rmc) at the studied formation temperature and graphical techniques from the resistivity and porosity logs. The water resistivity (Rw) was determined by graphical technique from the Pickett’s plot. On the other hand, the flushed zone resistivities (R,o) were estimated from the micro-spherically-focused log; after carrying out the necessary corrections for the mud cake thickness (hmc) and resistivity of mud cake (R.,.). The uninvaded zone resistivities (R,) were calculated from the available resistivity logs, deep induction log (ILD) and the dual-laterolog (LLS and LLD) taking into account the effect of borehole, adjacent beds and invaded zones. The determination of the shale content (Vsh) is achieved through mono-tools as the gamma ray, the self-potential, the resistivity and the neutron. Also, dia-tools were comprised the neutron-density, the sonic-density and the neutron-sonic. The matrix content of detected reservoir rocks is defined and differentiated into its main constituents; sandstone and limestone. The determination of corrected rock porosity (<IJ) was also executed in both clean and shaly rock units using density, neutron and sonic logs. The determination and discrimination of the fluid contents as water, movable and residual hydrocarbons were also carried out for both clean and shaly zones. The shale percentage distribution map for Lower Cretaceous shows six high shale percentage anomalies at Malha-1 well (51.05%), El Mazar-1 well (49.71%), NS 21-1 well (47.16%), Abu Roda-1 well (46.02%), Bougaz-1 well (44.80%) and Misri-1 well (40.36%) and the minimum percentage at Tineh-2 well (3.03%). This map shows the shale percentage increase from north at NS 21-1 well toward south at Malha-l well and toward southwest at Abu Roda-1 well and decreases toward nmthwcsl at Tinch-2 well. |