HYSTERESIS(1)

💖 NAME 💖

okay so bestie, let me put you on real quick — hysteresis is the tool that extracts relative permeability and capillary pressure curves, with hysteresis if it's enabled. that's it, that's the whole job. 🫶

✨ SYNOPSIS ✨

hysteresis DATA_FILE SATURATION_FILE OUTPUT_FILE TWOPHASE_SYSTEM [CELL_INDEX]

🦋 DESCRIPTION 🦋

So like, what does it actually do? It extracts the relative permeability curves and the capillary pressure curves — with hysteresis if enabled — for a cell in the model, and then it writes them as tables to a CSV file. iconic behaviour honestly. 💅

🎀 the arguments, one by one 🎀

• DATAFILE — this is your data file name, and it's the one that contains keywords like SGOF, EHYSTR, etc. etc. it's giving "the source of truth". 📂
• SATURATION_FILE — a file holding the saturations you're asking about. one saturation value per line, no cap. now, whether that's the gas or the water saturation depends on the TWOPHASE_SYSTEM parameter you pass in. specifically, it's the saturation of the first mentioned phase of the system you specified. so order matters, bestie, keep up. 👀
• OUTPUT_FILE — the name of the CSV file we're writing the relative permeability and capillary pressure curves to. there will be one line for every single saturation value from SATURATION_FILE. and each one of those lines contains the values [sw, krw, kro, pcow, krnSwMdc(So at turning point), Sn(trapped s) ]. (or the equivalent if you're running a GO or GW system — same energy, different letters.) 🌈
• TWOPHASE_SYSTEM — the two-phase system to use for outputting the first two phases. should be one of these strings, exactly:
  • WO — water-oil. water first, then oil.
  • GO — gas-oil.
  • GW — gas-water.
• CELL_INDEX — the cell index, and the default is 0. it gets used to determine the SATNUM/IMBNUM value that goes into the calculation. 🧚

ngl there's no hysteresis-free escape hatch here — if hysteresis is enabled in your data, the curves come out with hysteresis. that's the bit in the name, periodt.

and that's the whole page, bestie 💜 — this was hysteresis, from the User Commands chapter of the manual, dated April 2025. go forth and extract those curves, you absolute main character. 👑✨