The present work aims to detect the Phanerozoic sedimentary sub-basins and their hydrocarbon potentialities within the Qattara Ridge in the northern Western Desert, Egypt, through the interpretation of high-resolution land magnetic data. The in-depth relations between observed magnetic anomalies and the magnetic mineralogy of the underlying rocks and the associated chemical reactions are essential to understanding the hydrocarbon potentialities. A high-resolution land magnetic survey has been conducted covering an area of 3600 km², and several filters have been applied to the measured total field including reduction to pole, normalized source strength, tilt-depth and 3D Euler deconvolution with un-prescribed structural index, to accomplish the goals. Regularized focused inversion was applied to six selected profiles on the total magnetic intensity field to model variations in subsurface magnetic susceptibilities and to study the relation with hydrocarbon reservoirs in the area. Results show perfect structurally controlled sub-basins, with variable thickness of the sedimentary cover ranges for the Paleozoic to Miocene units. The depth of the top basement rocks ranges from 1500 to 7000 m. The calculated depths to the edges from magnetic analysis ranges from 292 to 3322 m. Some faults can be detected at 3900 m, and five possible sedimentary basins (depocenters) can be detected within the Qattara Ridge, trending NW–SE and N–S. Magnetic results also show that the central part of Qattara Ridge is affected by low magnetic anomaly, and many magnetization sources can be detected in the northern directions. The common trend in these sources is NW–SE. Most shallow depth to magnetic sources is concentrated at the northern part of the area, while the deeper sources are distributed in the west and south of the study area. The maximum depth recorded is about 3988 m. Inversion shows remarkable relations between the inverted magnetic susceptibilities and the different hydrocarbon productive and sealing zones in and close to the study area. The localized variations in the inverted anomalous magnetic susceptibilities in the Qattara Ridge were possibly produced by different intrasedimentary mineral magnetic phases developed near the surface due to hydrocarbon occurrences. Reducing gases, coming from the possible underlying hydrocarbon reservoir, play a critical role in the formation of these secondary magnetic minerals. The reservoir in the Qattara Ridge, based on the present study, is characterized by low magnetic susceptibility and low surface magnetic anomaly in the studied locations of productive wells. The interpretations show matching between the sedimentary thickness and position of the faults deduced from both the available drilled wells and seismic data with our magnetic results.

本工作旨在通过高分辨率陆地磁数据的解释，在埃及北部西部沙漠的Qattara山脊内检测生代沉积盆地及其油气潜力。所观察到的磁异常与下伏岩石的磁矿物学之间的深层关系以及相关的化学反应对于理解烃的潜力至关重要。进行了高分辨率的陆地磁测量，覆盖了3600 km ²，并且已将几种滤波器应用于测量的总场，包括极点减小，归一化源强度，倾斜深度和具有未指定结构索引的3D Euler反卷积，以实现目标。将规则化的集中反演应用于总磁场强度场上的六个选定剖面，以模拟地下磁化率的变化并研究与该地区油气藏的关系。结果表明，在古生代至中新世单元中，构造受控的次流域具有理想的沉积盆地厚度，其厚度范围也各不相同。顶部基底岩石的深度范围为1500至7000 m。磁分析计算的边缘深度为292至3322 m。在3900 m处可以检测到一些故障，在Qattara山脊内可以发现五个可能的沉积盆地（沉积中心），趋势为NW–SE和N–S。磁学结果还表明，卡塔拉山脊的中部受到低磁异常的影响，并且可以在北部方向检测到许多磁化源。这些来源的共同趋势是西北—东南。磁源最浅的深度集中在该区域的北部，而较深的磁源则分布在研究区域的西部和南部。记录的最大深度约为3988 m。反演表明，研究区域内和附近的反演磁化率与不同的油气生产和封闭带之间存在显着的关系。在卡塔拉山脊中，反常磁化率的局部变化可能是由于碳氢化合物的发生在地表附近形成了不同的沉积内矿物磁相而引起的。来自可能的潜在碳氢化合物储层的还原性气体在这些次级磁性矿物的形成中起关键作用。根据本研究，卡塔拉山脊的储层特征是在生产井的研究位置具有低磁化率和低表面磁异常的特征。解释表明，根据我们的磁学结果，从可用的钻井和地震数据中推断出的沉积厚度和断层位置之间是匹配的。