Evaluation of tectonic trends affecting hydrocarbon accumulation of El-Obaiyed Field, Bir Fouad area, Egypt, using gravity and dipmeter data

Abstract Bir Fouad is a significant region in the Western Desert of Egypt. It includes El-Obaiyed Field, which is considered the main Jurassic gas and condensate asset for the Shell-BAPETCO organization in the north part of the Western Desert. This field is strategically important due to its major contribution to Egypt's oil production. The purpose of the gravity data is to use disturbances in earth's gravitational field at the surface to outline the subsurface structures (faults) and determine the depth of the basement as the base of the planning area. The Bouguer gravity anomaly map was separated into regional (deep sources) and residual (shallow sources). Additionally, mathematical edge enhancement filters such as total horizontal derivative, tilt angle, and analytic signal were applied to the Bouguer data utilizing the vertical and horizontal derivatives to delineate the structural framework. Euler deconvolution and source parameter imaging methods were employed to estimate the depth of gravity sources and trends of structural elements. The gravity interpretation indicates that the main tectonics affecting the study area have east–west, east-northeast–west-southwest, west-northwest–east-southeast, northeast–southwest, and northwest–southeast trends, whereas the minor structures are aligned in north–south, north-northeast–south-southwest, and north-northwest–south-southeast trends. The results of depth estimation from applying 2D and 3D modeling, along with the available geologic information (the total depth and density logs for the available wells) illustrate a detailed basement structure map showing the basement configuration. The map reveals that the central and northwestern parts of the investigated area have shallower basement rock depths (3100 m), while the eastern and southwestern parts exhibit a deep basement structure, reaching more than 7000 m. The interpretation of advanced well-log data (the OMRI dipmeter) confirmed the resultant structural trends from the Bouguer gravity map that influence production of the Upper Safa and Lower Safa reservoirs in El-Obaiyed Field.