VFPPROD table-driven pipeline

VfpPipeline in neqsim.process.equipment.pipeline is a two-port process unit whose hydraulics come entirely from a supplied VFPPROD table. It can connect an upstream process to a downstream process, including through ordinary mixers. No pipe correlation or pressure-drop tuning is added to the approved table.

The accepted representation is VFPPROD, METRIC, GAS, WGR, GOR or OGR, THP, BHP, with a singleton ALQ axis. See the VFP export contract for header order, datum meaning and phase-volume units. BHP means the pipeline inlet pressure at the table provider’s datum; THP means arrival pressure. The caller must establish that this mapping is appropriate for the delivered table.

Configure and run

  1. Load a table using VfpTable.fromFile(path) (UTF-8) or fromString(deckText).
  2. Connect an inlet with new VfpPipeline(name, inlet) or setInletStream(inlet).
  3. Supply it with setVfpTable(table).
  4. Set the required thermal boundary with setOutletTemperature(value, unit).
  5. Set the required surface-volume definition with setTableArguments(provider).
  6. Add the inlet and pipeline to the ordinary ProcessSystem, then run it.

Executable Java examples, including a pipeline/mixer/export chain and a synthetic hand-checkable table, are in VfpPipelineTest and VfpTableTest. The same public classes and setters can be called from Python via JPype; a custom provider implements the VfpTableArguments interface.

Mode Input Result
Forward (default, or setForwardMode()) Inlet stream pressure Arrival pressure from THP inversion
Backward (setOutletPressure(value, unit)) Fixed arrival pressure getRequiredInletPressure(unit) from direct BHP lookup

Backward mode leaves the connected inlet pressure unchanged. The caller couples the reported required pressure to field deliverability or a network/adjuster. It is not a simultaneous network solution. A mixer takes the lowest connected pressure; it does not balance branch flows to a common tee pressure.

setNumberOfParallelLines(N) divides the provider’s total gas rate by positive integer N; all lines have the same WGR/GOR and the outlet retains total flow. The outlet is a clone of the inlet fluid at the computed arrival pressure and specified temperature, with a TP flash. Composition and total molar/mass flow are conserved. VFP tables do not determine heat duty, linepack, transient response, phase slip, geometry, temperature profile or mechanical design.

Explicit surface-volume definition

VfpTableArguments.calculate(stream) returns exactly three values: total gas rate in Sm3/day, WGR in Sm3 water/Sm3 gas, and GOR in Sm3 gas/Sm3 oil. Providers must preserve the inlet and match the table’s separation and metering basis. There is no default provider or default reference temperature/pressure.

StandardConditionsFlash(T, Tunit, P, Punit) clones the fluid and performs one multiphase TP flash at the supplied reference conditions. It sums gas, aqueous and oil phase volumes there, using phase mass flow divided by phase density. Its rate is the gas-phase volume per day, not the ideal-gas standard-volume conversion of all inlet moles. At the same T/P this matches the flashed gas’s actual m3/day volume. NeqSim’s stream Sm3/day getter instead uses ideal molar volume at global standard conditions; these definitions can differ by gas compressibility and by phase separation. Verify which convention the table provider used. A staged separator route or ideal-gas metering definition requires a custom provider.

Dry gas gives WGR zero and GOR positive infinity. VfpPipeline converts the provider’s GOR to OGR only for an OGR table, giving OGR zero for oil-free gas. An infinite GOR cannot be interpolated on a finite GOR axis and is rejected; choose a matching OGR table or explicitly supply the provider’s approved dry-gas GOR convention. No large GOR, range clamp or ratio-definition correction is invented. A file whose numerical columns were mislabeled cannot be detected from syntax alone: verify the provider’s definitions and data provenance.

getTableArguments() returns a defensive copy of the last successful run’s per-line gas rate, WGR and canonical GOR. getTableGasRatio() reports the actual GOR/OGR coordinate used. The ALQ coordinate is table.getAlq(). Diagnostics are last-successful-run results, not live calculations; after zero-flow bypass the arguments are null and gas ratio is NaN.

Table interpolation and rejection rules

Direct table.inletPressure(rate, thp, wgr, gasRatio, alq) returns bara. Rate is Sm3/day per line, THP is bara, and gasRatio is in the table’s declared GOR or OGR basis (unlike the provider interface, there is no implicit reciprocal here). outletPressure(rate, bhp, wgr, gasRatio, alq) solves for THP in bara. Axis getters return copies; getRateAxis supports Sm3/day and MSm3/day, getThpAxis supports bara, and ratio axes use Sm3/Sm3.

Interpolation is linear in each axis, including interactions between axes. Inversion checks the interpolated BHP at every THP knot for strict monotonicity, then solves the enclosing linear segment directly. Flat or nonmonotonic curves fail explicitly; no iterative tolerance or initial guess is needed. A singleton THP axis is usable only when the target equals its stored interpolated BHP.

Nonfinite, negative, unsorted or duplicate axes, nonpositive pressure, missing, extra or duplicate pressure records, fractional/out-of-range record indices, unsupported definitions and multiple ALQ values fail with an exception. Explicit numeric repeats such as 2*100 and Fortran D exponents are accepted; defaulted numeric cells such as 2* are rejected. The first keyword in an include/deck is read; later deck keywords are not interpreted as pressure rows.

Every lookup argument must lie inside its axis, including singleton axes. There is no extrapolation or clamping. A BHP target outside the inversion range fails. Zero flow fails by default; setAllowZeroFlow(true) explicitly bypasses table lookup and copies inlet pressure, including in backward mode. The outlet still uses the specified temperature. Injection tables, FIELD units and other rate or ratio definitions are outside the current supported scope.

Validation evidence and limits

The focused tests cover a hand-calculated midpoint to 1e-9 bar, all four interpolated axes, inversion endpoints/interior points, writer round-trip, forward/backward consistency, parallel lines, setup failures, malformed records, wet/dry reference flashes, stream ownership, conservation, Java serialization and ProcessSystem/mixer integration. These are synthetic software and analytical interpolation checks. They do not independently qualify an OLGA/Prosper table, a particular fluid’s phase equilibrium, or a field’s hydraulic model.