SURFACE
Gathering networks built on the same wells and fluid, solved and optimised together. Draw the network, solve it with loops and reverse flow, then allocate lift gas and set chokes against the constraints at any node.
WHAT IT DOES
A surface network decides how much the wells can deliver once they share pipelines, manifolds and a separator. Converge solves the steady-state network by Newton-Raphson on node pressures and signed branch mass rates: mass balances at every node, one pressure equation per branch, and the oil, gas and water split balanced too.
Because branch rates are signed, looped networks and reverse flow solve without special handling. Line search, step limits and a pressure floor keep the solve robust, and when it does fail, Converge names the worst node and branch and gives the likely physical reason instead of a bare error.
Wells use their own inflow and tubing on the project fluid, so a change in the separator pressure moves every well. Gas is accounted for from formation to sales, including lift gas recycled from the separator, and the optimiser allocates lift gas by equal slope or sets chokes against the constraints you place on any node.
KEY CAPABILITIES
A Newton solve that handles real network topologies and explains itself when it cannot converge.
Multiphase flow along real routes, not flat lines.
The equipment between the wells and the export point.
Each well has its own inflow and tubing on the project fluid.
Where every standard cubic foot of gas goes, and where velocity is too high.
Allocate lift gas and set chokes against the constraints.
WORKFLOW
Add wells, sources, joints, separators, sinks and a gas-lift manifold, and drag to connect them.
Inflow, tubing, choke and lift for each well, seeded from the project fluid.
Separator pressures, compressors and limits on rates or pressures at any node.
Auto-solve as you edit, or solve on demand, and read pressures and rates on the canvas.
Allocate lift gas for maximum oil or net value, or set chokes to honour constraints.
Download node, branch and well results as CSV.
VALIDATION
Every solve is checked for conservation: mass at every node, and gas from formation to sales when gas lift is recycled through the separator.
| Check | Reference | Converge | Tolerance |
|---|---|---|---|
| Mass balance at every node (V29) | Mass in equals mass out | Closes | 10⁻⁹ |
| Gas accounting with gas lift (V30) | Formation plus lift gas equals gas arrived; sales gas equals formation gas | Closes | 10⁻⁶ |
The network has no external comparison with another network tool yet; the benchmarks page says so. Below critical flow the choke uses a smoothing correction that the app flags as unverified.
INPUTS AND OUTPUTS
CONNECTED MODULES
Wells start from the project fluid, and the solved network becomes the surface half of the integrated forecast.
FAQ
Yes. Branch rates are signed, so looped networks and reverse flow solve without special handling.
Beggs and Brill (1973) with the revised flow-pattern map and optional Payne corrections, along hilly-terrain elevation profiles.
By equal slope across each well's concave lift curve (Kanu, Mach and Brown 1981), checked against a grid search, or by net value using oil netback, water handling and lift-gas cost.
Converge names the node and branch with the largest residual and gives the likely physical reason, such as a well that cannot flow against the manifold pressure.
Not yet. Mass and gas balances close to 10⁻⁹ and 10⁻⁶, and the benchmarks page lists the external comparison as outstanding.