Research and Application of In-Layer Secondary Perforation Technology in Daqing Oilfield

Aiming at the problems of severe casing damage, high randomness of perforation channel orientation, and insufficient perforation depth in in-layer secondary perforation for old well stimulation and development of low-permeability, low-pressure, and low-yield new wells in Daqing Oilfield, this study develops a downhole casing damage and perforation channel orientation detection method, optimizes secondary perforation technology, enhances the potential of remaining oil recovery in old wells, and explores the feasibility of in-hole secondary depth extension technology for new wells to provide technical support for efficient oil and gas reservoir development. For old well reperforation, directional perforation technology is adopted to achieve uniform hole distribution through phase dislocation design; for new well development, a combination of large-diameter and deep-penetration perforators is selected, and the feasibility of in-hole secondary depth extension is verified by self-developed perforation depth detection technology. The reliability of the technology is verified through optimization of process string structure and field tests (5–10 wells). The study establishes a downhole casing damage and perforation channel orientation detection method with a detection error controlled within ±2°; the azimuth error of secondary perforation in old wells is ≤±5°, casing damage is reduced by 30%, and the process success rate exceeds 90%. The sixty-arm caliper tester is first combined with orientation detection technology to achieve precise synchronous measurement of casing damage and perforation channel orientation; a directional phase dislocation perforation process is proposed to solve the problem of uniform hole distribution in secondary perforation; and the feasibility of in-hole secondary depth extension technology for new wells is verified, breaking through the limitation of single perforation depth. The research results provide key technical support for old well stimulation and efficient new well development in Daqing Oilfield, with significant economic benefits and application promotion value.