Injected water quality critically determines waterflooding effectiveness. The southern area of Gaoshen, a major deep reservoir block of the Gaoshangpu Oilfield (Jidong Oilfield), faces severe injection-well plugging, increased injection pressure, failing injection rates, and rapid production decline—necessitating urgent water-quality optimization. This study conducts reservoir sensitivity evaluation, injected water–reservoir compatibility analysis, and single-factor experiments on the effects of solid particles, suspended oil, and bacteria on permeability. Results show: (1) The reservoir exhibits moderately strong water sensitivity (critical salinity: 6000--10000~mg/L); current injected-... More >