Seismic Inversion for Post Stacked Data in Tarek Field, Western Desert, Egypt

Abstract

The study area; Tarek Field, is part of Khalda concession that is located in Matruh Basin at northern part of the western Desert of Egypt. It covers an area of about 105.73 square kilometre and is bounded by latitudes 30º 53' 02" N and 30º 59' 22" N and by longitudes 27º 31' 17" E and 27º 36' 59" E. The present work concerns with: Firstly, understanding the tectonic setting and structural development of the study area. Secondly evaluating the hydrocarbon potentialities in Tarek Field area, using 2D seismic data interpretation, post-stack seismic inversion and petrophysical analysis of the reservoir zones. 2D seismic interpretation objective in the study area is to build a regional geological view. Studying the reservoir system (Alam El-Bueib Members) was challenging due to the bad seismic data imaging. So, post-stack seismic inversion (model-based inversion) technique is applied to enhance the resolution of seismic data. Finally, evaluation ofreservoirphysical properties such as porosity, shale volume and saturations by petrophysical analysis that uses different well logs acquired, to provide reservoir zonation and net pays inside Alam El-Bueib 3G, 5, and 6 Members.

These objectives have been achieved through the following studies: • Description of the geology of the area, including a detailed discussion of the subsurface stratigraphic rock units of the North Western Desert with special reference to the area under investigation. Then emphasizing structures and tectonic evaluation of the north Western Desert, where the study area is located. • Then going to the second stage which is seismic data interpretation to clarify the structure elements effect on the study area. Firstly, four synthetic seismograms were constructed for seismic to well tie, after that twenty seismic sections were interpreted by identification of reflectors, picking and correlation of reflection horizons, closing loops, fault location detection. Different seismic processes were applied to aid in interpretation and appearance of horizons such as amplitude gain control (AGC) which clarify the continuity of the horizons. Another attribute was applied which is the variance for picking fault locations. Variance attribute sections identified the discontinuities (faults) easily. Investigation of the seismic sections show that the area is affected by a group of normal faults with different trends and throws, but mainly taking the direction northeast-southwest. The sections show clear flower structure where there is a major synthetic fault and other minor faults antithetic on it, also the roll ups appears clearly and the normal throw compensation at shallow successions which are due to the geologic inversion took place at the Western Desert (Syrian Arc system).