Investigation on Water Invasion Mode and Remaining Oil Utilization Rules of Fractured-Vuggy Reservoirs: A Case Study of the Intersection Region of S99 Unit in Tahe Oilfield

Fractured-vuggy reservoirs are a new target in carbonate oil and gas exploration development. Because of well-developed reservoir bodies, including fractures caverns, bottom water invasion can be observed oilfield development, with low utilization efficiency crude the reservoir. Accordingly, this study focused on intersection region S99 unit Tahe fractured-vuggy reservoirs. Based seismic data, bodies divided into three types—caverns, fractures, broken solution pores. Using same location condition assignment algorithm, four single-type models fused multi-scale discrete three-dimensional geological model fractured cavernous reservoirs, corresponding was established for numerical simulation. The single-well historical fitting precision exceeded 85%. Furthermore, development stages—initial stage production, peak production stage, liquid control stabilization scale injection stable. Streamlining sweep analysis determined distribution characteristics remaining It concluded that structure, were main controlling factors affecting fluid exchange among reserve zones calculated using streamline-based quantitative interwell flow method. Through source-sink analysis, relations derived, breakthrough modes further concluded: violent flooding, slow ascending cut, cut or intermittent production.