New Software Release

The Eclipse™ 2026.3 release includes developments enhancing the performance, usability, and functionality of the simulators.

Release updates

New user-defined argument (UDA) support in Eclipse 100 and Eclipse 300

User-defined argument (UDA) support has been added for top node pressure in the GRUPNET keyword to simplify the user input of gas compressors and allow more sophisticated gas rate optimization under velocity constraints. This facility is available in both Eclipse 100 and Eclipse 300. An option has been added to Eclipse 300 to allow compatibility with Eclipse 100 behaviour when both a fixed pressure and a vertical flow performance (VFP) table are specified for the same group.

Negative depth support in Eclipse 300

Eclipse 300 adds an option to specify a negative reference depth for wells, supporting workflows where the grid datum lies above sea level.

New and improved functionality:

Eclipse 2026.3 delivers a set of targeted improvements that strengthen stability, robustness, restart behaviour, and reporting clarity.

For Eclipse 100:

• Specifying the MULTFLT keyword in the SCHEDULE section no longer resets the threshold pressures specified in the THPRESFT keyword to the default value.
• Cumulative tracer injection/production reporting when the GEFAC keyword is used now includes the full tree of efficiency factors and is consistent with the equivalent reporting for fluids.
• Multipliers specified on the restart step are now only applied once.
• An issue with pressure initialization when unlocked local grid refinements (LGRs) were added at restart has been fixed.
• An issue with fluid flow between the global grid and LGRs in parallel runs has been fixed.
• Table output in the PRT file has been improved so that IJK grid indices with more than three digits are represented correctly.

For Eclipse 300:

• Directional mobilities have been made more robust. The RKTRMDIR keyword is now compatible with multicomponent water and with the parallel option, and non-directional surfactant endpoints are now mapped correctly onto all three directions in directional models.
• Region separator solid composition reporting has been corrected in the PRT file.
• Grid information output in the PRT file has been improved, especially for local grids and parallel runs.