Study on Fluid Potential Calculation Method and Adjustment Strategy of Fractured-Caved Carbonate Reservoirs

Abstract Fractured-caved carbonate reservoirs typically exhibit multi-medium characteristics, comprising pores, fractures, and large-scale cavities. The coexistence of these complex flow systems gives rise to intricate fluid migration behavior and presents considerable challenges in controlling water production and enhancing oil recovery. Adjusting the fluid potential based on reservoir hydrodynamics is considered an essential approach for well pattern management in such reservoirs. Nevertheless, the existing fluid potential regulation theories are still constrained by incomplete formulations and a lack of reliable quantitative characterization tailored for fractured-caved carbonate settings. To address these limitations, this study develops a fluid potential calculation and characterization methodology specifically adapted to the flow mechanisms of fractured-caved carbonate reservoirs. Through a comparative analysis of the relative magnitudes of various potential energy components within fractured-caved units, the primary controlling factors influencing the fluid potential distribution were systematically identified, leading to the establishment of a theoretical representation model. Based on this framework, bottom-hole pressure data from representative production wells were processed to normalize the fluid potential distribution across the reservoir units. By incorporating production performance analysis, development potential assessment, and inter-well connectivity evaluation, well-specific adjustment strategies were formulated, and a practical fluid potential adjustment policy chart was constructed. The proposed methodology was applied to 27 well groups in the T10 oilfield of the Tarim Basin, China. The calculated fluid potential fields for different fractured-caved units enabled the design of differentiated adjustment schemes targeting specific potential wells. Field implementation over a five-year period resulted in a cumulative oil production increase of approximately 746000 t, while maintaining the average water cut consistently between 75% and 85%. These outcomes demonstrate the reliability and practical value of the proposed approach. The fluid potential calculation method and the adjustment policy chart presented in this work offer effective technical solutions for optimizing the development of similar fractured-caved carbonate reservoirs. Keywords: fractured-caved carbonate reservoirs; fluid potential; development potential evaluation; reservoir production optimization; hydrodynamic adjustment strategy