Aquifer Model Matching
Spreadsheet
31 rows x 5 columns
| A | B | C | D | E | |
|---|---|---|---|---|---|
| 1 | Aquifer Model Matching | ||||
| 2 | Aquifer Properties | ||||
| 3 | Permeability (K) | 50 | mD | ||
| 4 | Thickness (h) | 50 | ft | ||
| 5 | Porosity (φ) | 0.2 | fraction | ||
| 6 | Outer Radius (ra) | 15000 | ft | ||
| 7 | Reservoir Radius (rr) | 3000 | ft | ||
| 8 | Encroachment Angle (θ) | 360 | degrees | ||
| 9 | Total Compress. (ct) | 7E-06 | 1/psi | ||
| 10 | Water Viscosity (μw) | 0.5 | cP | ||
| 11 | Initial Pressure (Pi) | 4000 | psia | ||
| 12 | |||||
| 13 | Computed Aquifer Params | ||||
| 14 | Wi (bbl) | 1208520059 | bbl | ||
| 15 | J (bbl/D/psi) | 21.99525668 | bbl/D/psi | ||
| 16 | Wei (bbl) | 33838561.65 | bbl | ||
| 17 | |||||
| 18 | Stepwise Water Influx | ||||
| 19 | Time (days) | Pr (psia) | Pa (psia) | qw (bbl/D) | We (bbl) |
| 20 | 0 | 4000 | 4000 | 0 | 0 |
| 21 | 365 | 3900 | 3905.099173 | 2199.525668 | 802826.8689 |
| 22 | 730 | 3800 | 3805.359189 | 2311.683294 | 1646591.271 |
| 23 | 1095 | 3700 | 3705.372448 | 2317.402405 | 2492443.149 |
| 24 | 1460 | 3600 | 3605.373124 | 2317.694033 | 3338401.471 |
| 25 | 1825 | 3500 | 3505.373158 | 2317.708903 | 4184365.221 |
| 26 | 2190 | 3400 | 3405.37316 | 2317.709662 | 5030329.247 |
| 27 | |||||
| 28 | Summary | ||||
| 29 | Total We | 5030329.247 | bbl | ||
| 30 | Aquifer pressure drop | 594.6268401 | psi | ||
| 31 | We / Wei | 0.14865671 | fraction |
Description
Estimate cumulative water influx using the Fetkovich aquifer model and match aquifer parameters (permeability, outer radius) to observed pressure-production data. The Fetkovich model uses a productivity index (J) and maximum encroachable water (Wei) to compute stepwise water influx.
Diagnostic: If standard MBE without water influx gives declining OOIP estimates, the reservoir has water drive. Matching the aquifer model stabilizes the OOIP.
Workflow
- Inputs: Aquifer geometry (h, ra, rr, θ, φ), fluid (ct, μw), pressure history
- Step 1: Compute aquifer volume (Wi), PI (J), and max influx (Wei)
- Step 2: At each time step, compute water influx rate and cumulative We
- Step 3: Track average aquifer pressure decline
- Output: Stepwise water influx table for MBE input
How to use this blueprint
- In Excel, go to the Petroleum Office ribbon tab and click Blueprint Manager
- Search for Aquifer Model Matching
- Click on the blueprint to preview the spreadsheet template
- Click Insert to place it into your worksheet. Modify the input values to match your data.