双河油田A区长6油层分层注水先导试验与效果评价OA

To address the poor performance of water injection development caused by strong heterogeneity in the ultra-low permeability Chang 6 reservoir of Block A,Shuanghe Oilfield,this study evaluates the adaptability of layered water injection technology.Based on detailed reservoir characterization,eight injection-production well groups were selected for a pilot test.Dynamic monitoring data were comprehensively utilized to conduct acoupled analysis of the impacts of geological properties,injection technology,and injected water quality on development performance.The trial demonstrated that layered water injection significantly improves the sweepefficiency(averaging 94.8%in effective well groups)and successfully reverses the production decline trend,turning both the natural and comprehensive decline rates negative(e.g.,the comprehensive decline rate in Well Group G dropped to-6.2%).However,the technical effectiveness has clear application boundaries:the lower limit of res-ervoir permeability is approximately 1.2×10-3 μm2,and water quality is a critical success factor.Well groups using produced water reinjection performed poorly due to severe exceedances in suspended solids,oil content,and sulfate-reducing bacteria(SRB>85 cells/mL).Layered water injection technology is suitable for this area,but its successful application strongly depends on the synergy among"geological optimization,pre-cise engineering,and standard-compliant water quality."It is recommended that this technology be promoted in zones meeting the permeability criteria and that core water quality control indicators,specifically SRB≤10 cells/mL and oil content≤10 mg/L,be strictly enforced.