水驱优势通道下微观潜力分布及改变流线挖潜

根据中高渗油藏优势通道孔喉分布特征，建立了具有不同优势通道发育规模的二维刻蚀模型，对优势通道下剩余油微观分布及演变特征进行了研究；通过分析不同改变流线动用方法适应性，初步揭示了优势通道下剩余油改变流线动用机制；结合油藏数值模拟，量化了改变流线动用策略。结果表明，提高驱替速度可使弱优势通道下剩余油大幅降低，而强优势通道变化较小；根据优势通道下剩余油赋存形态、形成机制，将其分成了4类，即死角式、并联式、包围式、绕流式，其中前两类受优势通道规模、驱替速度影响极小，而后两类仅在优势通道规模较小时，才会随驱替速度增加而大幅减小。应以利用与克服优势通道的角度去设计流线动用改变方式，在流线动用方式合理改变时，强优势通道注采比应适当降低，而弱优势通道相反。

Microscopic Distribution of Potentially Recoverable Oil During the Waterflooding of Preferential Petroleum Migration Pathways and Enhanced Oil Recovery Through Streamline Alteration

Two-dimensional etching models were constructed with varying levels of preferential petroleum migration pathway (PPMP) development based on the pore-throat distribution characteristics of PPMPs in mid-to-high permeability reservoirs, for studies on the microscopic distribution of residual oil in PPMPs and their evolutionary characteristics. By analyzing the adaptability of different methods for altering streamline mobilization, we have taken the first steps towards revealing the mechanism of streamline mobilization alterations in the residual oils of PPMPs. We also quantified strategies for altering streamline mobilization via numerical simulations of oil reservoirs. The results indicate that increases in displacement speed can greatly reduce the quantity of residual oil in weakly preferred migration pathways, whereas the changes that occurred in strongly preferred migration pathways were relatively minute. The residual oils in PPMPs were divided into four types according to the morphology of their storage and formative mechanisms, namely, dead angle types, parallel types, enveloping types, and circumfluent types. The first two types were almost completely unaffected by the scale of PPMPs and displacement speed, whereas the two latter types showed significant decreases with increases in displacement speed if the PPMPs are relatively small in scale. Methods for altering streamline mobilization should be designed to overcome preferential pathways. When the appropriate alterations are made in streamline mobilization methods, the injection-production ratio of strongly preferred pathways should be suitably decreased, and the reverse should occur for weakly preferred pathways.