Sandstone oil reservoirs with huge bottom water and high permeability are generally developed with high flow rate. After long-term water flooding (LTWF), the water flooding characteristics are quite different from that of original reservoir. In this paper, the effects of the PV number, viscosity, and displacement rate during LTWF are studied through experiments. The mechanism is analyzed based on analysis of changes in oil composition, rock mineral composition and wettability. The oil-water relative permeability curves, oil recovery and wettability were obtained with new experiments methods, which avoids the oil metering error by measuring oil and water separately. The research indicates that when the viscosity increases, the water phase permeability decreases, the residual oil saturation increases, and the water content rate increases earlier. A higher water flooding rate results in a higher ultimate recovery. A higher asphaltene content results in a higher viscosity and more oil-wet reservoir conditions. After LTWF, the wettability tends to water-wet, which is more favorable for heavy oil recovery. Moreover, LTWF reduces the clay content, which creates a more water-wet surface and a larger reservoir pore throat environment. This research provides insightful characteristics of offshore sandstone oil reservoirs, which can be used to enhance oil recovery.

通常以高流速开发具有巨大底部水和高渗透率的砂岩油藏。经过长期注水（LTWF）后，注水特征与原始水库有很大的不同。本文通过实验研究了LTWF期间PV数，粘度和位移速率的影响。在分析油成分，岩石矿物成分和润湿性变化的基础上分析了机理。通过新的实验方法获得了油水相对渗透率曲线，采油率和润湿性，通过分别测量油和水避免了油计量误差。研究表明，当黏度增加时，水相渗透率降低，剩余油饱和度增加，含水率提早增加。较高的水驱率导致较高的最终采收率。较高的沥青质含量导致较高的粘度和更多的油湿储层条件。LTWF后，润湿性趋于水润湿，这对于重油采收更有利。此外，LTWF降低了粘土含量，从而创建了更湿的表面和更大的储层孔喉环境。这项研究提供了具有远见的海上砂岩油藏特征，可用于提高石油采收率。这会产生更湿的表面和更大的储层孔喉环境。这项研究提供了具有远见的海上砂岩油藏特征，可用于提高石油采收率。这会产生更湿的表面和更大的储层孔喉环境。这项研究提供了具有远见的海上砂岩油藏特征，可用于提高石油采收率。