SGWFLET
PROPS
SWGFLET defines the relative permeability and capillary pressure parameters for the water-gas LET family of models. Both the gas and water phases should be made active in the model via the GAS and WATER keywords in the RUNSPEC section. This keyword should only be used in two-phase models containing the gas and water phases only, that is the oil phase must be absent. See section 8.2.6Saturation Table Generation - LET Functionsand Lomeland et al.237 Lomeland F., Ebeltoft E. and Thomas W.H., 2005. A New Versatile Relative Permeability Correlation. Paper SCA2005-32 presented at the International Symposium of the Society of Core Analysts held in Toronto, Canada, 21-25 August, 2005.,238 Lomeland F. and Ebeltoft E., 2008. A New Versatile Capillary Pressure Correlation. Paper SCA2008-08 presented at the International Symposium of the Society of Core Analysts held in Abu Dhabi, UAE, 29 Oct. – 2 Nov., 2008. 239 Lomeland F., Hasanov B., Ebeltoft E. and Berge M., 2012. A Versatile Representation of Up-scaled Relative Permeability for Field Applications. Paper SPE 154487-MS presented at the EAGE Annual Conference & Exhibition incorporating SPE Europec held in Copenhagen, Denmark, 4-7 June 2012.and 240 Lomeland F., 2018.Overview Of The Let Family Of Versatile Correlations For Flow Functions. Paper SCA2018-056 presented at the International Symposium of the Society of Core Analysts held in Trondheim, Norway, 27-30 August 2018.for further information on the model.
Lomeland F., Ebeltoft E. and Thomas W.H., 2005. A New Versatile Relative Permeability Correlation. Paper SCA2005-32 presented at the International Symposium of the Society of Core Analysts held in Toronto, Canada, 21-25 August, 2005.
Lomeland F. and Ebeltoft E., 2008. A New Versatile Capillary Pressure Correlation. Paper SCA2008-08 presented at the International Symposium of the Society of Core Analysts held in Abu Dhabi, UAE, 29 Oct. – 2 Nov., 2008.
Lomeland F., Hasanov B., Ebeltoft E. and Berge M., 2012. A Versatile Representation of Up-scaled Relative Permeability for Field Applications. Paper SPE 154487-MS presented at the EAGE Annual Conference & Exhibition incorporating SPE Europec held in Copenhagen, Denmark, 4-7 June 2012.
Lomeland F., 2018.Overview Of The Let Family Of Versatile Correlations For Flow Functions. Paper SCA2018-056 presented at the International Symposium of the Society of Core Analysts held in Trondheim, Norway, 27-30 August 2018.
The keyword is used as a replacement for the SGWFN keyword for two-phase gas-water systems, and the LET series of keywords cannot be combined with the standard set of relative permeability keywords.
Note
This is an OPM Flow specific keyword and will therefore cause an error in the commercial simulator.
Notes:
The keyword is followed by NTSFUN definitions as declared on the TABDIMS keyword in the RUNSPEC section, with each definition consisting of the above 17 LET parameters.
Each table is terminated by a “/” and there is no “/” terminator for the keyword.
Note there a two versions of the LET functions, LET237 for two-phase flowing conditions and LETx241 Lomeland F. and Ebeltoft E., 2013. Versatile Three-phase Correlations for Relative Permeability and Capillary Pressure. Paper SCA2013-034 presented at the International Symposium of the Society of Core Analysts held in Napa Valley, California, USA, 16-19 September, 2013. for three-phase flowing conditions. This keyword implements the LET version for a gas-water system.
Lomeland F. and Ebeltoft E., 2013. Versatile Three-phase Correlations for Relative Permeability and Capillary Pressure. Paper SCA2013-034 presented at the International Symposium of the Society of Core Analysts held in Napa Valley, California, USA, 16-19 September, 2013.
The functions are dependent on the drainage and imbibition cycle of the wetting phase as well as drainage and inhibition cycle number, since a reservoir may undergo several flooding events. To account for this the system defines the flooding event using the three saturations: Sw, So, and Sg together with the state of the three saturations during the flooding event. The saturation state can be Increasing, Decreasing, or Constant, for a given flooding event cycle number (n). Thus, Sw(D), So(C), Sg(I), or DCI1, means the water phase is decreasing, the oil phase is constant and the gas phase is increasing for the primary or first cycle (n equals one). This is case for when gas is migrating into the reservoir rock and displacing the initial water contained with the reservoir.
Note
All the LET parameters are dependent on the flooding event and flooding cycle, and thus are expected vary as such. To be clear, the values of SWCR, Lg, Lw etc. should be different for each flooding cycle.
See also the SGOFLET– Gas-Oil LET Relative Permeability Functions, and SWOFLET – Water-Oil LET Relative Permeability Functionskeywords in this section, that may be used for three-phase systems.
Parameters
| No. | Name | Description | Field | Metric | Lab | Default |
|---|---|---|---|---|---|---|
| 1 | SGL | SGL is a real positive number less than one that defines the connate gas saturation, that is smallest gas saturation in the LET function. | dimensionless | dimensionless | dimensionless | 0,0 |
| 2 | SGCR | SGCR is a real positive number greater than or equal to SGL and less than one, that defines the critical gas saturation, that is the largest gas saturation for which the gas relative permeability is zero. | dimensionless | dimensionless | dimensionless | 0,0 |
| 3 | LGAS | LGAS is a real positive number that defines the LET Lower empirical parameter Lg for the gas phase with the associated water phase in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 4 | EGAS | EGAS is a real positive number that defines the LET Elevation empirical parameter Eg for the gas phase with the associated water phase in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 5 | TGAS | TGAS is a real positive number that defines the LET Top empirical parameter Tg for the gas phase with the associated water phase in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 6 | KRTGAS | KRTGAS is a real positive number less than one, that defines the relative permeability of gas at the maximum gas saturation Krgt in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 7 | SWL | SWL is a real positive number less than one, that defines the connate water saturation, that is the smallest water saturation in the LET function. | dimensionless | dimensionless | dimensionless | 0,0 |
| 8 | SWCR | SWCR is a real positive number greater than or equal to SWL and less than one, that defines the critical water saturation, that is the largest water saturation for which the water relative permeability is zero, Swirr in equations. | dimensionless | dimensionless | dimensionless | 0,0 |
| 9 | LWAT | LWAT is a real positive number that defines the LET Lower empirical parameter Lw for the water phase with the associated gas phase in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 10 | EWAT | EWAT is a real positive number that defines the LET Elevation empirical parameter Ew for the water phase with the associated gas phase in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 11 | TWAT | TWAT is a real positive number that defines the LET Top empirical parameter Tw for the water phase with the associated gas phase in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 12 | KRTWAT | KRTWAT is a real positive number less than one, that defines the relative permeability of water at the maximum water saturation (normally the maximum water saturation is one) Krwt in the LET relative permeability equations. | dimensionless | dimensionless | dimensionless | 1,0 |
| 13 | LPC | LPC is a real positive number that defines the gas-water LET Lower empirical parameter L in the LET capillary pressure equation. | dimensionless | dimensionless | dimensionless | 1,0 |
| 14 | EPC | EPC is a real positive number that defines the gas-water LET Elevation empirical parameter E in the LET capillary pressure equation. | dimensionless | dimensionless | dimensionless | 1,0 |
| 15 | TPC | TPC is a real positive number that defines the gas-water LET empirical parameter T in the LET capillary pressure equation. | dimensionless | dimensionless | dimensionless | 1,0 |
| 16 | PCIR | PCIR is a real positive number that defines the gas-water capillary pressure at connate water saturation (SWL) in the LET capillary pressure equations. | psia | bars | atm | 0,0 |
| 17 | PCIT | PCIT is a real positive number that defines the gas-water threshold capillary pressure at the maximum water saturation in the LET capillary pressure equations. | psia | bars | atm | 0,0 |
Example
The following example uses the SWGFLET keyword to define two relative gas-water relative permeability tables, based on NTSFUN equals two on the TABDIMS keyword in the RUNSPEC section.
--
-- SGWFLET – GAS-WATER LET REL. PERMEABILITY FUNCTIONS (OPM FLOW KEYWORD)
--
SGWFLET
-- SGL SGCR L-GAS E-GAS T-GAS KRT-GAS
-- SWL SWCR L-WAT E-WAT T-WAT KRT-WAT
-- L-PC E-PC T-PC PCIR PCIT
-- ------- ------ ------- ------- ------- -------
0.00000 0.0000 1.00000 1.00000 1.00000 1.00000
0.00000 0.0000 1.00000 1.00000 1.00000 1.00000
1* 1* 1* 1* 1* / TABLE NO. 01
0.00000 0.0000 1.00000 1.00000 1.00000 1.00000
0.00000 0.0000 1.00000 1.00000 1.00000 1.00000
1* 1* 1* 1* 1* / TABLE NO. 02
Here the SGWFLET keyword parameters are all set to their default values.
| Note This is an OPM Flow specific keyword and will therefore cause an error in the commercial simulator. |
|----------------------------------------------------------------------------------------------------------|
| Note All the LET parameters are dependent on the flooding event and flooding cycle, and thus are expected vary as such. To be clear, the values of SWCR, Lg, Lw etc. should be different for each flooding cycle. |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|Manual source: parts/chapters/subsections/8.3/SGWFLET.fodt