Feasibility Study of Secondary Injection in Block Loss Area of Block A

To tap the potential of residual oil damaged zones and achieve stable production in oil fields, this paper studies Block A as an example, systematically evaluating the feasibility of secondary injection for these zones. Based on thorough research into dynamic comparisons of primary injection, stability of damaged zones, pressure control limits, and analysis of remaining potential, combined with numerical simulations and dynamic monitoring data, it clarifies the dynamic characteristics differences during the injection phase in damaged zones. Compared to non-damaged zones, damaged zones exhibit “three lows and one high” features: low injection pressure, low injection intensity, low utilization of oil layers, and high water cut. By comparing the flow field changes and residual oil saturation variations in different well groups under water injection, the distribution patterns of residual oil in various well groups are determined, identifying their characteristics. It is clear that the main types of residual oil in damaged zones are inter-layer interference-type residual oil and imperfect injection-production type residual oil. Residual oil primarily accumulates in thin poor reservoirs and at the top of thick oil layers, and is widely distributed in areas where water injection has ceased and is controlled. Through residual potential evaluation, analysis of damage conditions, and determination of injection pressure boundaries for different well groups, the feasibility of secondary injection in damaged zones is confirmed. The research results provide theoretical support and technical optimization directions for tapping the potential of residual oil in damaged zones and developing secondary injection.