ESP
ESP traverses require a more complex solver to reconcile gas separation efficiency and head degradation, when possible. ESP traverses have four possible scenarios, depending on data availability:
- A solver is used to compute gas separation efficiency by finding the value which satisifies a traverse from WHP -> discharge node equaling gauge discharge pressure
- Using measured intake pressure and calibrated discharge pressure, solve ESP head degradation directly by scaling head from the pump curve at the computed in situ rate (post-gas separation)
Simultaneously solve for gas separation efficiency and head degradation using the gauge intake pressure and wellhead pressure as fixed nodes in the system. A discharge pressure is computed from measured intake across the pump as well as a discharge pressure computed from wellhead pressure down to discharge. The final solution is the gas separation efficiency and head degradation that yields the smallest error computing from both directions.
Simultaneously solve for intake pressure and head degradation using the wellhead pressure as a fixed node in the system. Gas separation efficiency is assumed constant as defined in the ESP table for that well / assembly. A discharge pressure is computed from intake across the pump as well as a discharge pressure computed from wellhead pressure down to discharge. The final solution is the intake pressure and head degradation that yields the smallest error computing from both directions.
In a VLP situation, it is assumed that gas separation efficiency and head degradation is known from recent history. Since there are no gauge intake or discharge pressures available in a VLP calculation, the only variable solved for is intake pressure. A discharge pressure is computed from intake across the pump as well as a discharge pressure computed from wellhead pressure down to discharge. The final solution is the intake pressure that yields the smallest error computing from both directions.
