Production profile - oil rate (bbl/d)
Base oil
Polymer oil
Polymer-earned barrels
Polymer gross liquid (right)
Deliverable if not debottlenecked (deferred gap)
Surface chain load
Year
10
NPV vs injected concentration - where is the optimum?
Incremental NPV
Your current C_inj
NPV optimum
Injectivity blockage zone (RF > RF*)
NPV sensitivity - what moves the screening result
Each bar sweeps one driver across its range, holding the rest at current values. The widest bars are what a screening decision hinges on - here, oil price and the reservoir/conformance inputs dominate; polymer chemistry is second-order. This is the honest answer to "which assumptions matter".
How C_inj earns the oil - conformance, not viscosity (light oil)
This is a light-oil carbonate (Thamama-type, μ_oil ~0.3 cP). The water-oil mobility ratio is already favourable - polymer is not here to thicken water to match oil. It diverts injection out of swept hi-K streaks (100-1000 mD) into unswept low-K matrix (1-10 mD). Incremental oil scales with heterogeneity (Vdp), not oil viscosity - and is capped by injectivity: push resistance factor past RF* and the tight matrix plugs, injectivity collapses, oil falls. High TDS degrades the achievable viscosity, so an ATBS-grade polymer is assumed. The optimum concentration is set by injectivity in tight rock, not by chemical cost.
Base water injection
Polymer water injection
Injection-efficiency gain: viscous polymer drive replaces the same reservoir voidage with less injected water. Raise it and watch polymer injection drop below base - the "less water, same oil" case.
Polymer concentration → back-production → de-rate
Injected conc (C_inj, flat)
Back-produced conc (C_back)
PW-treating
Separation
Dehydration
Only the polymer slug fraction of injected water carries polymer; the rest of the field injection is plain water. Back-produced concentration = C_inj × slug × (1 − retention) × breakthrough(year). Each unit's de-rate ramps with C_back up to its cap - so the whole surface constraint story is downstream of one number you set at the injectors. Raise C_inj and watch de-rate, chemical cost and the binding link all move together.
Gathering & processing chain - click a unit to trace WBS / CBS / CAPEX
Select a unit
Click any unit in the chain above to see its load, the polymer de-rate applied, and the CAPEX it drives.
Added EOR CAPEX by work package
Total EOR CAPEX
Constraint migration - base vs polymer, by year
The whole thesis in one view: as polymer adds oil and liquid, the binding link moves - and it binds earlier and harder than the base case. Where base and polymer differ is where EOR has created a new facility problem.
How it connects - WBS drives CBS drives the decision
WBS - what gets built
CBS - where the cost lands
The binding constraint (orange in the chain) decides which WBS element must be built; the WBS element maps to a CBS cost code; the CBS total feeds CAPEX, which sets UDC and NPV. That chain - constraint → equipment → cost code → economics - is the decision. When the binding link migrates from the oil side to the water side under polymer, the dominant CAPEX migrates with it.