Depleted Gas Reservoir Underground Storage (UGS) Modeler
Models seasonal p/Z material balance, cushion gas vs working gas inventory splits, water drive encroachment hysteresis, and API RP 1171 maximum injection pressure limits.
Depleted Reservoir Geological Baseline
Storage Cycling Envelope & Deliverability
Depleted Reservoir Underground Storage (UGS) Mechanics
Depleted gas reservoirs are ideal for seasonal energy storage due to known geology, existing trapping seals, and installed surface infrastructure. Sizing is governed by classical $p/Z$ volumetric material balance and safety mandates defined in API RP 1171.
1. Cushion Gas vs. Working Gas Material Balance
In a volumetric depletion reservoir without significant water drive, gas in place scales linearly with $p/Z$:
Cushion gas is the permanent inventory required to maintain reservoir pressure at $(p/Z)_{\text{min}}$ so that the field can supply required flow rates into high-pressure transmission networks during peak winter demand.
2. API RP 1171 Maximum Storage Pressure Criterion
Overpressuring storage reservoirs beyond their historical discovery pressure risks inducing shear failure along faults or exceeding the caprock entry capillary pressure. API RP 1171 stipulates that $P_{\text{max}}$ must not exceed the initial reservoir pressure unless verified by extensive geomechanical caprock step-rate core testing.
Input / Output Units
Configure global unit system preset or individual parameter dimensions.