This work attempted to understand the behavior of the Upper Cretaceous Nezzazat and Lower Cretaceous–Carboniferous Nubia sandstone reservoirs in response to production-induced depletion and fluid injection for enhanced hydrocarbon recoveries from the October oil field, Gulf of Suez, Egypt. Pore pressure (PP), vertical stress (Sv) and minimum horizontal stress (Shmin) magnitudes were modeled based on well logs, drilling data and subsurface measurements. The latest measurements indicated 11.7–12.7 MPa pressure drop (ΔPP) in the Nezzazat reservoirs, while the Nubia sandstone reservoir was depleted by 19–21 MPa. Revised PP and Shmin gradients offer a narrow mud weight window of 9–10.7 PPG (pore pressure gradient) if the entire Lower Miocene–Carboniferous section was planned to be drilled with a single casing in the infill/injector wells. A more conservative approach will be to drill the depleted reservoirs with 5.5–9.3 PPG mud window and case separately, although that may incur an additional cost. Based on the PP–Shmin poro-elastic coupling, stable stress path values of 0.61 and 0.65 are interpreted in the Upper and Lower reservoirs, indicating depletion-induced normal faulting is unlikely to occur at the present rate of depletion. The reservoir stability threshold during pressurization was assessed for fluid injection optimization to sustain production and curtail the bypassed oil. The maximum allowable pressure build-up during injection was estimated using various possible pore pressure–stress coupling scenarios at their maximum depletion state. Based on the PP–Shmin coupling approach, maximum pressure increments of 23 and 27 MPa can be permitted in the depleted Nezzazat and Nubia sandstone reservoirs during injection, without exceeding the lower limit of caprock Shmin, as applicable for both the reservoirs. This will ensure the geomechanical stability of the reservoirs as well as the caprock integrity. This geomechanical study provides crucial comprehensions regarding the optimization of drilling, production, and fluid injection by reducing the risk of reservoir instabilities and formation integrity.

这项工作试图了解上白垩统Nezzazat和下白垩统-石炭纪努比亚砂岩储层的行为，以响应由生产引起的衰竭和注水，以提高埃及苏伊士湾10月油田的油气采收率。孔隙压力（PP），垂直应力（Sv）和最小水平应力（Shmin）大小是根据测井曲线，钻井数据和地下测量结果建模的。最新测量结果显示，Nezzazat油藏的压降（ΔPP）为11.7-12.7 MPa，而努比亚砂岩油藏的压降为19-21 MPa。如果计划在填充/注入井中使用单个套管钻探整个下中新统-石炭纪剖面，则修订后的PP和Shmin梯度可提供9-10.7 PPG（孔隙压力梯度）的较窄泥浆重量窗口。较为保守的方法是分别用5.5–9.3 PPG的泥窗和套管钻探枯竭的储层，尽管这可能会产生额外的成本。基于PP-Shmin孔隙弹性耦合，在上，下层储层中的稳定应力路径值分别为0.61和0.65，这表明在目前的枯竭率下，由枯竭引起的正常断层不太可能发生。评估了增压过程中的储层稳定性阈值，以优化流体注入，以维持产量并减少旁路油。使用各种可能的孔隙压力-应力耦合情景在其最大消耗状态下估算了注入过程中的最大允许压力累积。根据PP–Shmin耦合方法，在注入过程中，耗尽的Nezzazat和Nubia砂岩储层中允许的最大压力增量为23和27 MPa，而不会超过适用于两个储层的盖层Shmin的下限。这将确保储层的地质力学稳定性以及盖层完整性。这项地质力学研究通过降低储层不稳定性和地层完整性的风险，为优化钻井，生产和流体注入提供了至关重要的理解。