Rock and saturation properties

Rock records

Each physical layer uses [Kxy, Kz, porosity, thickness, z_cells]. Only the final boundary-rock record may use [Kxy, Kz, porosity]. Permeabilities are non-negative, porosity lies in [0, 1], thickness is positive, and cell counts are positive integers.

Saturation expressions

krw, krn, and pcap are restricted Python expressions that must reference sw. Approved positional NumPy functions include np.maximum, np.minimum, np.clip, np.where, np.exp, np.log, and related safe numerical functions.

Saturation records

Every safu row has 11 entries: swi, sni, wetting and non-wetting end points, entry pressure, three exponents, capillary threshold, low-saturation control, and number of points. Endpoint saturations lie in [0, 1] and sum to at most one. At least two table points are required.

Hysteresis and boundary behavior

ehystr configures EHYSTR. pvmult controls boundary pore volume: positive values apply a multiplier, zero may use producers, and -1 disables it.