Well and choke simulation in NeqSim

Overview

NeqSim combines well inflow performance relationships with hydraulic flowline models and production chokes to represent surface networks. A WellFlowlineNetwork assembles wells, optional chokes, and pipelines into branches that are gathered in manifolds for steady-state or transient calculations.

Well inflow models

WellFlow supports several inflow performance relationships that can either solve for outlet pressure from a specified flow or compute flow from a specified outlet pressure:

• Production index (PI) – Constant PI using squared-pressure drawdown.
• Vogel – Empirical oil well relationship using a reference test to derive the productivity curve.
• Fetkovich – Gas deliverability using C and n coefficients in squared-pressure space.
• Backpressure with non-Darcy term – Deliverability equation (p_r^2 - p_{wf}^2 = a \cdot q + b \cdot q^2) where the quadratic term captures turbulence/non-Darcy skin. The model is solved in either direction, with guards for insufficient drawdown.
• Table-driven inflow – User-supplied pairs of bottom-hole pressure and flow rate are sorted and linearly interpolated to compute flow or back-calculate the required pressure for a requested rate.

All models can switch between computing outlet pressure or flow via solveFlowFromOutletPressure(boolean), enabling backpressure solves from downstream network pressure when desired.

Choke representation

Production chokes are modeled as ThrottlingValve instances using IEC 60534 sizing. Chokes can be attached per branch and run in steady-state or transient mode. Valve travel and characterization are captured through the underlying valve model, and choking conditions can be toggled and tuned at the valve level.

Network coupling

WellFlowlineNetwork wires wells and optional chokes into PipeBeggsAndBrills flowlines, collects them in manifolds, and optionally sends the combined stream downstream. The network offers steady-state and transient execution modes, supports target endpoint pressure solving, and can propagate arrival pressures back to well outlets for iterative backpressure calculations.