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OH – ST - ET: Analysis of Dynamic Data in Shale Gas Reservoirs – Part 2
p 14/18
Let us now compare the model performance with the other models over a 10-year production
scenario:
Comparison of 10-year forecasts
We can see that in this case, desorption is playing a small effect even after 10 years, because
we are staying quite high above the langmuir pressure. This could change if we consider a
lower operating FBHP for our 10-year production plan.
In conclusion, desorption effect plays a little role in the production contribution in our
particular case. The nonlinear numerical MFHW is an interesting model for production
forecasting, and the analytical MFHW can act as a starting model for calibration.
6 - Drainage area and reserves
As we have said in the previous section, because of the extremely low mobility
k/
induced by
a very low permeability formation, the well is draining mostly the immediate proximity of the
reservoir only. This is in consistency with what we observe in existing operating shale gas
wells. Let us observe the pressure field around the well for two time steps: one at the last
pressure data points after 8 months of production, one after 10-year production forecast:
0
2000
4000
6000
8000
10000
12000
14000
16000
Gas rate [Mscf/D]
0
1E+9
2E+9
3E+9
4E+9
5E+9
6E+9
7E+9
Gas volume [scf]
Analytical MFHW
Equiv single fracture
NL numericalMFHW w desorption
Non linear numericalMFHW
0
10000 20000 30000 40000 50000 60000 70000 80000 90000 1E+5
Time [hr]
2000
4000
6000
8000
10000
Pressure [psia]
Production history plot (Gas rate [Mscf/D], Pressure [psia] vs Time [hr])