Hajer Azaiez

Integrated gravity and seismic investigations over the Jebel Es Souda-Hmaeima structure: implication for basement configuration of the eastern frontal fold-and-thrust belt of Tunisian Atlasic Mountains

A gravity and seismic analysis was conducted over and around Jebel Es Souda-Hmaeima, located on the eastern border of the Tunisian Mountains between the Atlasic block to the west and the Pelagian Block to the east, as part of a study to investigate the subsurface structures. These data, together with outcrop geology, well data, and measurements of physical properties of rock samples, were integrated with a new interpretation of the tectonic model of Jebel Es Souda-Hmaeima anticline. This structure represents a backfolded anticline associated with a steep east-vergent thrust above a blind thrust fault along the base of Triassic formations. The proposed model emphasizes the role of transpressional deformation along deep-seated basement faults and has implications for petroleum generation, migration, and entrapment in central Tunisia.تم تطبيق قيس شاذات بوجيه وقيس الذبذبات السيسميكية لدراسة تركيبة جبل لسودة – حميمة ، الواقع بالجبال الشرقية التونسية بين المنطقة الأطلسية والمنطقة البلاجية الساحلية.مكننا تحليل شاذات بوجيه والمقاطع السيسميكية ، إضافة إلى المعطيات الخاصة بالجيولوجيا السطحية والآبار العميقة والخصائص البتروفيزيائية للأحجار ، من تحديد تفسير جديد للأنموذج التكتونيكي لجبل لسودة –حميمة.هذا الأنموذج الجديد يبرز أهمية التركيبة المتصلة بتحركات الفوالق وبالخصائص البتروفيزيائية للأحجار الترياسية كما يحدد مدى تأثيراتها على تكوين ، تنقل وخزن الموارد البترولية.

Aeromagnetic study of buried basement structures and lineaments of Sahel region (Eastern Tunisia, North Africa)

This study presents original results regarding the use of aeromagnetic to explore deep subsurface structuring in southern part of Tunisian Sahel petroleum province (Eastern Tunisia, North Africa). Several filters and techniques were applied to the total magnetic intensity (TMI) grid. First, an adequate reduce to the pole (RTP) grid was generated. The RTP map shows 17 positive and negative anomalies associated with short- and long-wavelength amplitude anomalies. Positive anomalies correspond to high magnetic basement structures estimated from seismic lines in the area. Circular anomalies are also distinguished locally and can be explained by Cretaceous magmatic rocks recognized in numerous petroleum wells. Second, specific qualitative and quantitative filters (e.g., residual-regional separation, horizontal tilt angle (TDX), tilt angle (TILT), total horizontal derivative of tilt angle (THDTILT)) were applied to elucidate the form and the extent of buried magnetic anomalies and lineaments. The resulting deep structural map revealed the presence of NW-SE, N-S, and E-W regional magnetic basement structures and lineaments and a regional tectonic node surrounding Henchir Keskes-Agareb-Mahres-Hachichina area. Two magnetic inversion models calculated across the study area highlight west to east crustal thinning trend and permit depth to basement estimation. These results are valuable for future conventional and unconventional petroleum exploration in this underexplored southern part of Sahel plain.

Basin structuring and hydro-geophysical characterization of Upper Cretaceous and Eocene fractured deep carbonate reservoirs in the Hajeb Layoun-Jelma-Ouled Asker area (Central Tunisia)

In the Hajeb Layoun-Jelma-Ouled Asker-Oued El Hajal folded pull a part basin, situated in Central Tunisia, the shallow and deep Miocene groundwaters are often over exploited. The sedimentary basins, in this area, contain important carbonate deep reservoirs not yet exploited. Turonian (Bireno-Douleb Formations), Maastrichtian (Abiod Formation), and Ypresian (El Gueria Formation) limestones constitute the most important fractured reservoirs in this region. The present study combine geological, hydrogeological, and geophysical data, using 2D seismic reflection, to determine the spatial distribution and the deep structuring of these carbonate reservoirs. Isochron and isopach maps, generated for the study area, highlight the effect of tectonics in structuring these carbonate reservoir horizons. This effect is well presented along the folded structures and the major fault directions: NE-SW, NW-SE, N-S, and E-W responsible of the reservoir compartmentation. Indeed, subsurface faults as well as thickness and facies variations of these carbonate reservoirs should play a key role in the hydraulic flows and the distribution of principal aquifers. Knowledge and highlights of this structuring represent a subsurface modeling for future deep hydrogeologic exploration with proposed fictitious wells in the study area.