The N150 base oil–WTI spread has widened to CNY 820/t (calculated from WTI at USD 102.22/bbl and USD/CNY 6.7127: landed duty-paid cost ~CNY 4,940/t vs. current domestic quote of CNY 5,760/t). This is +CNY 90/t above the August average of CNY 730/t and breaches the industry-accepted fair-value range (CNY 650–780/t). The primary driver is concentrated maintenance at two major refineries in East China during early September, pushing N150 operating rates down to 61.3% (SNSUC supply-chain terminal data) — the lowest this year. Concurrently, fuel oil futures surged 2.54% to CNY 4,476/t, directly raising marginal blending costs for lubricants: fuel oil accounts for ~35% of blending cost (industry standard) as a key diluent. Demand remains firm: domestic lube apparent consumption rose 2.1% MoM in September, with heavy-duty industrial oil orders staying elevated. Import substitution is now economically actionable. SK Korea and ExxonMobil Singapore N150 cargoes scheduled for mid-September arrival in Shanghai are quoted at CNY 5,620–5,680/t CIF, CNY 90–140/t below domestic spot — fully compatible with SNSUC’s blockchain carbon footprint verification, meeting CBAM Phase III upstream traceability mandates. Risks: WTI > USD 104/bbl or CNY depreciation beyond 6.75 would rapidly erode import margins; early resumption of refinery operations before 25 Sep could compress the spread back to <CNY 720/t within five trading days. SNSUC recommends: importers lock in vessel slots for late-September to early-October arrivals at ≤CNY 5,650/t; traders hedge rising blending costs via long fuel oil positions; all N150 contracts must embed SHA-256 carbon data fields on-chain to ensure zero CBAM correction.