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NETL has developed a state-of-the-art fractured reservoir modeling package consisting of five components,

1. a fracture network generator (FRACGEN),
2. a flow simulator (NFFLOW),
3. graphical output software (Fracout),
4. a PC-based User Interface (Fracflow),
5. ancillary programs for input data analysis and/or manipulation.

FRACGEN/NFFLOW represents a significant advancement in the art of gas reservoir simulation by being the first model to readily simulate gas flow and drainage in fractured reservoirs with a discrete, irregular, stochastic fracture network using a large number of fractures. Reservoir modeling with this software is appropriate if:

• The reservoir produces relatively dry gas, with little interference from water or oil.
• The reservoir rock (matrix) has less than 1 millidarcy permeability.
• Variations in fracture apertures, density and connectivity are the predminatn factors effecting gas flow migration.
• Flow conductors are oriented nearly vertical and are strata-bound (extend from bottom to top of beds that can be modeled individually).
• Faults do not divide the reservoir into tightly sealed compartments or produce significant offsets in the productive strata.

The models are available for download through the Knowledge Managment Database CD/DVD Retrieval System under the title "Naturally Fractured Natural Gas Reservoir Simulator: FRACGEN & NFFLOW". Several different publications related to NFFLOW/FRACGEN can be found at the Office of Scientific and Technical Information, OSTI, Information Bridge by seraching for either FRACGEN or NFFLOW.

The most recent release is intended for PC application in a Windows environment. FRACGEN/NFFLOW was designed as a simulator that models fluid flow through complex fracture networks efficiently on standard desktop computers. The intended audience for this program includes small independant resource producers, academic and governmental researchers. NETL is interested in expanding the network of active users that can assist us in identifying potential bugs in the current version as well as guiding the most useful development into the future. For inclusion in future releases, please send bug fixes, modifications and comments to FRACGEN/NFFLOW Development. For notification of new releases please send an email to FRACGEN/NFFLOW Releases with the subject "Add to Release Distribution List".

The animation on this page displays sample output values for pressure from 22 timesteps.  The animation runs though three times.  A series of wells run diagonally across the display area.  Click here for an enlarged view that more clearly shows the well locations.

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