`EHYSTR`

Recognised by the OPM Flow parserPROPS

The EHYSTR keyword defines the hysteresis model and associated parameters when the hysteresis option has been activated by the HYSTER variable on the SATOPTS keyword in the RUNSPEC section. Both the Carlson185 Carlson, F. M. “Simulation of Relative Permeability Hysteresis to the Non-Wetting Phase,” paper SPE 10157, presented at the SPE Annual Technical Conference & Exhibition, San Antonio, Texas, USA (October 5-7, 1981). and Killough186 Killough, J. E. “Reservoir Simulation with History-dependent Saturation Functions,” paper SPE 5106, Society of Petroleum Engineers Journal (1976) 16, No. 1, 37-48. models are available.

Carlson, F. M. “Simulation of Relative Permeability Hysteresis to the Non-Wetting Phase,” paper SPE 10157, presented at the SPE Annual Technical Conference & Exhibition, San Antonio, Texas, USA (October 5-7, 1981).

Killough, J. E. “Reservoir Simulation with History-dependent Saturation Functions,” paper SPE 5106, Society of Petroleum Engineers Journal (1976) 16, No. 1, 37-48.

Notes:

The keyword is terminated by a “/”.

Records: Fixed number of records
Record count: 1
Items per record: 14

Parameters

No.	Name	Description	Type	Field	Metric	Lab	Default
1	`curvature_capillary_pressure_hyst` manual: `HYSTRCP`	HYSTRCP is a positive real value that defines the Killough curvature parameter for capillary pressure hysteresis model. The value should range from 0.05 to 0.10. This item is not supported by OPM Flow and should be defaulted (1*).	DOUBLE				0.1
2	`relative_perm_hyst` manual: `HYSTMOD`	An integer value that determines the relative permeability hysteresis model to be used depending on the phase and the wettability of the system. HYSTMOD should be set to one of the following values:	INT	HYSTMOD	Non-Wetting Phases	Wetting Phase	0
3	`curvature_param_killough_wetting` manual: `HYSTREL`	HYSTREL is a positive real number that defines the Killough’s wetting phase relative permeability curvature parameter. This parameter is only applicable if HYSMOD is set to either 4 or 7. This item is not supported by OPM Flow and should be defaulted (1*).	DOUBLE				1.0
4	`mod_param_trapped` manual: `HYSTSGR`	HYSTSGR is a positive real number that sets a scaling parameter for the trapped non-wetting phase saturation in the Killough model. This item is not supported by OPM Flow and should be defaulted (1*).	DOUBLE				0.1
5	`limiting_hyst_flag` manual: `HYSTOPT`	A defined character string that determines if the hysteresis model should be activated for relative permeability, capillary pressure, or both, and should be set to one of the following: BOTH:apply hysteresis modeling to both relative permeability, and capillary pressure curves. PC:apply hysteresis modeling to capillary pressure curves only. KR:apply hysteresis modeling to relative permeability curves only.	STRING				BOTH
6	`shape_cap_press_flag` manual: `HYSTSCAN`	A defined character string that determines the shape of Killough capillary pressure scanning curves when secondary reversal occurs, that is for a drainage, imbibition, drainage cycle. RETR: Secondary drainage curves re-traverses the same scanning curve. NEW: Secondary drainage curves follows a new scanning curve and further reversals also generate a new scanning curve. Only the RETR option is supported by OPM Flow.	STRING				RETR
7	`init_fluid_mob_flag` manual: `HYSTMOB`	A defined character string that determines how to apply the mobility control correction invoked by the MOBILE variable on the EQLOPTS keyword in the RUNSPEC section. HYSTMOB should be set to one of the following: DRAIN:Only the drainage curve end-points are modified. BOTH:Both the drainage and imbibition curve end-points are modified. The Mobility Control option is not supported in OPM Flow so this parameter has no effect and will be ignored. This item should be defaulted.	STRING				DRAIN
8	`wetting_phase_flag` manual: `HYSTWET`	A defined character string that sets the wetting phase between oil and gas in three phase systems and should be set to one of the following: OIL: Oil is set as the wetting phase between oil and gas, and the oil relative permeability with respect to gas is determined by HYSTMOD for the wetting phase. GAS: Oil is set as the non-wetting phase between oil and gas, and the oil relative permeability with respect to gas is determined by HYSTMOD for the non-wetting phase. Note for all the above cases the gas relative permeability is always modeled as a non-wetting phase. Note oil is always the wetting phase to gas in two phase systems. This item is not supported by OPM Flow and should be defaulted (1*).	STRING				OIL
9	`baker_flag_oil` manual: `HYBAKOIL`	Baker model one or model two relative permeability oil phase hysteresis option used in the commercial compositional simulator. This item is not supported by OPM Flow and should be defaulted (1*).	STRING				NO
10	`baker_flag_gas` manual: `HYBAKGAS`	Baker model one or model two relative permeability gas phase hysteresis option used in the commercial compositional simulator. This item is not supported by OPM Flow and should be defaulted (1*).	STRING				NO
11	`baker_flag_water` manual: `HYBAKWAT`	Baker model one or model two relative permeability water phase hysteresis option used in the commercial compositional simulator. This item is not supported by OPM Flow and should be defaulted (1*).	STRING				NO
12	`threshold_saturation` manual: `HYTHRESH`	Killough’s hysteresis threshold saturation value used in the commercial compositional simulator. This item is not supported by OPM Flow and should be defaulted (1*).	DOUBLE				0.0
13	`fix_wetting_phase_killough` manual: `HYSWETRP`	An integer value that determines if a modification to Killough’s wetting phase relative permeability hysteresis model is enabled to reduce the departure of the scanning curve from the region between the drainage and imbibition curves. 0: Modification is disabled. 1: Modification is enabled. Note this option is only used if HYSTMOD (Item 2) is set to 4 or 7.	INT				0
14	`enable_pc_scaling` manual: `HYSPCSCL`	An integer value that determines if capillary pressure scaling should be enabled to correct the construction of the scanning capillary pressure curve. 0: Capillary pressure scaling is disabled. 1: Capillary pressure scaling is enabled. This option is currently disabled by default but this is likely to change as the correction is believed to be a bug fix. For more information see #6383. This is an OPM Flow specific item that is not supported by the commercial simulator.	INT				0

Example

--
-- HYSTERESIS MODEL AND PARAMETERS
--
-- PC-CUR MODEL RELPERM TRAPPED OPTION SHAPE MOBILIT WET
-- HYSTRCP HYSTMOD HYSTREL HYSTSGR HYSTOPT HYSTSCAN HYSTMOB HYSTWET
EHYSTR
0.1 0 0.1 1* KR 1* 1* 1* /
The above example defines the hysteresis model and parameters used in the Norne model. Here the default value is used for the Killough curvature parameter for capillary pressure hysteresis mode, the Carlson hysteresis model is used for the non-wetting phase and SATNUM for the wetting phase, 0.1 is used for Killough’s wetting phase relative permeability curvature parameter (this parameter is ignored because the Carlson model has been selected), the default values for the trapped non-wetting phase saturation in the Killough mode (again, this parameter is ignored because the Carlson model has been selected, and the hysteresis modeling is only applied to relative permeability curves).

Manual source: parts/chapters/subsections/8.3/EHYSTR.fodt