FORGAS 10.8.1 ENHANCEMENTS
1. GAS TANKS WITH WATER INFLUX: PREDICT WATER / GAS RATIOS
For wells producing from water influx gas tanks, the user can now choose to have the
water/gas ratio calculated assuming homogeneous flow (diffuse flow). The diffuse flow
option uses gas/water relative permeability data and the fractional flow equation to
calculate the water/gas ratio.
The gas/water relative permeability may be specified using 3 different methods:
1. specified gas/water relative permeability curves
2. from correlations: Honarpour (1982), Wyllie (1950), Corey (1954) or Corey
3. using the cumulative production data to solve for the relative permeability
2. OIL TANKS: COREY POWER-LAW PERMEABILITY MODEL
For oil tanks (with or without water influx), the Corey Power-Law function is now
available as an option for all types of relative permeability (gas with respect to oil, water
with respect to oil, oil with respect to gas, oil with respect to water). The Corey Power-
Law functions are also known as the modified Brooks-Corey (1964) relationships.
3. READ AND WRITE RESERVOIR INPUT DATA FILE
FORGAS will now create the reservoir input data file (.MBX). This allows sharing of
reservoir models with IAM.
FGI will import the reservoir input data file (.MBX) and allow users to select which
reservoirs to add to their FORGAS input data file.
4. SELECT PVTTOOLBOX FOR RESERVOIR FLUID MODELLING
FGI now allows the user to select to use PVTToolbox to model the fluids in tank
reservoirs. This allows for better comparison of results with IAM.
5. OIL AND GAS TANKS: OTHER ENHANCEMENTS
1. Now an improved optimizer is used for reservoir calibration to adjust parameters
to match measured reservoir pressures.
2. Now the original gas in place for the gasifer is updated during the calibration
process, which improves the calibration and forecast results.
3. For the Havlena and Odeh analytical procedure for aquifers which use the
Fetkovich water influx method in oil or gas tanks, previously the water influx term
was calculated as the difference between the previous time step pressure and
the current pressure. This has been changed to be the difference between the
original reservoir pressure and current pressure. This change makes the
calculations consistent with those described in the original Havlena and Odeh
paper. As a result of this change, the following FORGAS Quality Assurance
Files have improved Havlena and Odeh calculations for reservoirs which use the
Fetkovich water influx method: FG10601.FGW, FG10602.FGW, FG10604.FGW,
FG10701.FGW, FG10702.FGW, and FG10705.FGW.
4. More detailed error messages are now provided.
5. The default button for the Net to Gross Multiplier in oil tank reservoirs is now
6. Cosmetic improvements to the Echo, Maxi and Mini reports (such as using 7
digits instead of 6 digits to allow scientific notation to be fully displayed) have
7. FORGAS will now retrieve and report the new relative permeability coefficients
which are based on cumulative production data AFTER the reservoir is
8. Previously FORGAS would not calibrate reservoir parameters if there were any
reservoirs which were connected to other reservoirs in the input data file. Now
FORGAS will calibrate all reservoirs, even if there are reservoirs which are
connected. Note that the reservoir connections will NOT be calibrated; during the
calibration process each reservoir will be treated as if it were a stand-alone
reservoir. FGI will no longer warn that the reservoir calibrations will be ignored for
6. MBAL LINKAGE IMPROVEMENTS
1. A problem which prevented usage with MBAL versions of 10.0 or larger has
2. The ability to link with MBAL version 13.0 has been confirmed.
3. A problem which prevented using MBAL on computers in which the computerdate was configured as year-month-day has been fixed.
7. REMOVAL OF DYNAMIC LINKAGE TO ECLIPSE
Support for the dynamic link with ECLIPSE (which uses the OPEN ECLIPSE
interface) has been removed from this version because the version of ECLIPSE
required to use this linkage (2010.1) is no longer available.
Note that this change does NOT affect the Read ECLIPSE Output option, which is
still supported because it is not dependent on the version of ECLIPSE.
Now when an input data file which contains data for an ECLIPSE reservoir (dynamic
link) is read, FGI will write the following message:
ERROR: Reservoir has been declared as an ECLIPSE RESERVOIR
but this linkage is no longer supported. Either use
Read ECLIPSE Output or use FORGAS 10.7.1 instead.
This reservoir will be converted to Read ECLIPSE Output.
Now FGI will convert the reservoir to be one of type Read ECLIPSE Output and will
preserve as much data as applicable. FGI will convert the simulator file to be Read
ECLIPSE Output simulator file.
8. NEW INSTALLATION PROCEDURE
1. To be consistent with other Schlumberger software, now the Schlumberger
installation procedure is used. This means the software is installed into the
Schlumberger folder instead of the SPT Group folder.
2. Support for Windows 10 systems has been added.
3. FORGAS no longer supports licenses using USB dongles (hardware keys). All
users must use FlexLM licenses.
4. Unnecessary files are no longer installed.
9. OTHER IMPROVEMENTS
1. Previously if the fluid property table was completely empty (i.e. not a single
character in the file), FORGAS would terminate with an error message about the
end-of-file during read. Now FORGAS provides a more understandable error
Page 10 of 10
FORGAS 10.8.1 Release Notes
2. The e-mail address listed in the Help -> About FORGAS has been corrected to
be firstname.lastname@example.org. Hypertext links are now used for the e-mail
and website addresses. The support address listed in the user manual has also
been updated to be email@example.com.
3. In NeoViewer, the Help Topics have been removed from the Help menu (Help ->
Help Topics), because the format of that help file is not compatible with Windows
7 or 10.
4. FBOGraph and FBOExport can now handle empty FBO files without
10. CHANGES OF WHICH YOU NEED TO BE AWARE
1. In Windows 10, when copying dates from Excel, if the year is listed as 2 digits
(rather than as 4 digits), the year and day of the month will be reversed in FGI.
For example, 31-12-16 will be shown as December 16, 1931. To avoid this
problem, in Excel, change the format of the date to use a 4 digit year (e.g. 2016-
12-31) before copying the values, to allow FGI to correctly copy the dates. Note
that this is not a problem in Windows 7, only in Windows 10. This also tends to
happen when using existing spreadsheets from previous versions of Windows,
rather than spreadsheets newly created in Windows 10.
2. Custom unit sets which were created in previous versions of FORGAS (e.g.
FORGAS 10.7.1) will not be recognized by this new version. This is because the
new version of FGI reads and writes the custom unit set into the directory
where UserName is the name of the user (e.g. MTrick)
The previous version put the custom unit sets into the directory named:
\Users\ UserName \AppData\Roaming\SPT Group\FORGAS\
To allow the software to use custom unit sets from previous versions, copy the
contents of the old directory:
\Users\ UserName\AppData\Roaming\SPT Group\FORGAS\
\Users\ UserName \AppData\Roaming\Schlumberger\FORGAS\