Research and Application of Rapid Zonal Isolation Technology in Deep and Ultra-Deep Wells: A Case Study of the Sichuan Basin

Zonal isolation technology plays a critical role in enhancing operational efficiency and reducing testing cycles during multi-zone well testing and production in oil and gas fields. However, conventional isolation techniques face significant challenges in deep and ultra-deep well applications, where elevated temperatures, extreme pressures, high-strength casings (e.g., 155 V grade), and complex downhole conditions are prevalent. To overcome these limitations, this study introduces an innovative rapid zonal isolation technology incorporating three key advancements: (1)a high-strength composite anchoring mechanism, (2) a reversible injection flow control system, (3) an integrated hydraulic setting and injection assembly. Leveraging these developments, we engineered an injection-type bridge plug and an integrated setting-injection tool, enabling simultaneous anchoring, sealing, setting and cement squeezing in a single run. Comprehensive laboratory evaluations and field trials demonstrate the following findings: (1) The injection-type bridge plug maintains reliable performance under extreme conditions (204 ℃, 105 MPa differential pressure, 155 V casing), while the integrated tool eliminates premature setting and mud-induced blockages, (2) Field application confirm that the proposed technology reduces zonal isolation time from 16.5 to 6.3 days per interval by minimizing tripping operations. This work provides a technically robust solution for efficient well testing in deep and ultra-deep wells, with direct applicability to the Sichuan Basin and analogous high-pressure, high-temperature reservoirs.