Shale Gas Flow Simulation

FRACGEN/NFFLOW, a fractured reservoir modeling software developed by the NETL Geological and Environmental Sciences on-site research group, has 5 components designed to simulate gas flow and drainage in fractured reservoirs with a stochastic network of discrete fractures. These state of the art components are:

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

Discrete fractures are stochastically generated using one of three models.

Model 1 generates randomly located fractures, although the connectivity controls can be used to produce various degrees of clustering.

Model 2 generates fracture swarms (elongated clusters), whereby the swarms are randomly located and can overlap.

Model 3 generates uniform pattern fractures and can condition the network to known fracture locations as observed in a borehole.

All fractures extend vertically through the entire height of a layer. The models allow multi-layered networks, in which fracture networks are generated for several stacked layers, with a user-specified percentage of fractures in each layer extending into the overlying layer.

A First In Gas Reservoir Simulation

FRACGEN/NFFLOW represents a significant advancement in 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 predominant 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.

Download "Naturally Fractured Natural Gas Reservoir Simulator: FRACGEN & NFFLOW", the NETL fractured reservoir modeling software today. Related publications can be found at the Office of Scientific and Technical Information, OSTI, Information Bridge by searching for either FRACGEN or NFFLOW.

FRACGEN/NFFLOW Software Compatibility

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.  A series of wells run diagonally across the display area. This enlarged version of the shale gas flow animation more clearly shows the well locations.