Accounting for Adsorbed Gas-in-Place for Shale Gas Plays

The flowing material balance (FMB) analysis provides the capability to account for adsorbed gas-in-place (GIP) for shale gas plays and for coalbed methane (CBM) plays.

To perform an FMB on a well that has adsorbed gas:

1. Launch an entity for analysis.

2. Open the Properties Editor, and select Formation / Rock, Adsorption.

3. Enter values for the Langmuir Volume (V_LS) and Pressure (P_LS).

4. Click the FMB thumbnail.

An FMB analysis line will be automatically fitted through the data. However, at this point, the adsorbed gas volume has not been taken into account.

5. In the Material Balance Options section, select Adsorption. This will correct the data to include adsorbed gas, and will shift the data points up.

6. Reposition the analysis line through the data points. The calculated OGIP will now include an adsorbed volume (OGIP_A).