Geomechanical assessment of the Lower Turonian AR-F limestone Member, Abu Gharadig Field, Egypt: Implications for unconventional resource development

• Published in: Frontiers in earth science (Lausanne) Vol. 10
• Main Authors: Farouk, Sherif, Sen, Souvik, Abu-Alam, Tamer, Al Kahtany, Khaled, Abioui, Mohamed
• Format: Journal Article
• Language: English
• Published: Frontiers Media 08.12.2022; Frontiers Media S.A
• Subjects: Abu Gharadig; AR-F carbonate; Egypt; geomechanics; unconventional reservoir
• ISSN: 2296-6463; 2296-6463
• DOI: 10.3389/feart.2022.1041453

This study evaluates the unconventional reservoir geomechanical characteristics of the Lower Turonian Abu Roash-F (AR-F) carbonates from the Abu Gharadig field, onshore Egypt, which has not been attempted before. The interval dominantly consists of planktic foraminifera and micrite matrix. The AR-F marine carbonate is organic-rich (0.59–3.57 wt% total organic carbon), thermally mature (435–441°C T max ) and falls within the oil generation window. The studied interval is very tight with up to 2.6% porosity and 0.0016–0.0033 mD permeability with the wireline log-based brittleness index ranging between 0.39–0.72 which indicates a less brittle to brittle nature. AR-F exhibits a hydrostatic pore pressure gradient with minimum horizontal stress (S hmin ) varying between 0.66–0.76 PSI/ft. Safe wellbore trajectory analysis was performed for deviated and horizontal wells to infer the mud pressure gradients required to avoid wellbore instabilities. Based on the inferred in-stress magnitudes and considering an NNE regional maximum horizontal stress orientation, none of the fractures are found to be critically stressed at present day. To produce from the AR-F, hydraulic fracturing is necessary, and we infer a minimum pore pressure increment threshold of 1390 PSI by fluid injection to reactivate the vertical fractures parallel to regional minimum horizontal stress azimuth.