1. Modelling Unconventional Wells with Resolve and Reveal Juan Biörklund (Gauloise Energía) and Georg Ziegler (Wintershall Holding)

2. Reveal Features Adsorption PVT Modelling Diffusion Reservoir Modelling
Designed to study specialized near well bore effects and assess their impact on the production from the reservoir
Adsorption
Diffusion
Rock Mechanics
Rock Failure
Fracturing
PVT Modelling
Reservoir Modelling
Well Modelling
Chemical EOR
Water Chemistry

3. Capabilities (Resolve & Reveal)
Quick Calculations
Tight reservoirs with complex well geometries
Systems with up to 20,000 wells with 100 wells being drilled per month
Shale Oil / Gas Wells
Horizontal, inclined and fractured wells
Gas adsorption, diffusion, directional stress dependent permeability variations etc...

4. Concept
Dimensionless transient reservoir response capturing the well, fracture and reservoir geometry
Dimensionless pseudo-pressure pseudo-time (pD tD)
Match this response to production history
Modify reference parameters k and phi(rw2)
Adjust PVT reference conditions for pD and tD

5. Concept (cont.) Perform predictions
Use matched pD tD and super-position to predict Pwf
Transient IPR for rate estimation
Well scheduling
Automate the procedures using visual workflows
Model definition and workflow in Resolve
Indirectly access simulation capabilities of Reveal

6. Shale Gas Well

7. Microseismic Frac Xf is 3 -5 x longer than seen in FracPro,
proved with Microseismic
Multi-Fracs does not interfear near wells (approx. 300m)
(Sketch not same as seen)

8. Fracture Input Parameters

9. Fracture Finite Element Grid

10. History Match History match a shale well - Additional Input Data -
Young’s modulus ( bar).
Poisson’s ratio (0.275).
Biot’s coefficient (0.75).
Langmuir adsorption curve (70 scc/g).
Fracture permeability variation (no data).
Compaction table (Palmer & Mansoori – SPE ).
Fracture geometry and properties (NRT Log & Gohfer)

11. History Match
History matching : Reveal model

12. Input Parameters

13. History Match: Reveal Model
Measured Pressure
Calculated Pressure
Rate

14. pD tD Curves - Resolve pD tD curves Why What they are
A method that allows us to perform rapid calculations with complex well geometries
What they are
Dimensionless transient reservoir response that captures the well, fracture and reservoir geometry

15. pD tD Curves - Resolve
pD tD curves (pseudo-pressure pseudo-time)

16. pD tD Curves - Resolve Optimization
Resolve - Powerful Optimizing Tool on Field Level Production
Why Resolve
Handles large number of wells
Easy to analyze well performance
Infinite scenarios to find best match

17. pD tD Curves Use GAP with Eclipse / Reveal / pD tD pd td curve
One well
Reveal
Model
pd td
curve
Two well
Eclipse

18. Resolve: Modelled vs. History

19. Shale Oil Well

20. Oil Models: Resolve & Reveal
Issues
No gas break-through seen in the simulation
What is the frac geometry causing this behaviour?
Tight Reservoir Module uses only analytical method (pD tD)
3 Fracs simulated as one, inflow problems
Solutions
Model the fracs explicitly with Reveal frac gridding option
Evaluate resulting pD tD curves from analytical vs. numerical
Detailed Resolve model explains where GOR increase when pressure is below Pb at certain fracs

21. Resolve pD tD Match
Dimensionless parameters – no geometry info

22. Resolve Workflow

23. Control Reveal with Resolve
Setup Resolve model and ran several cases to test sensitivity on different parameters and interaction between them such as:
Porosity, Stimulated K, Matrix K
Fracture half length, Fracture height
Stimulated Rock Volume (SRV)
Compressibility
RESOLVE Logic

24. Resolve / Reveal Sensitivities

25. Oil Reservoir Model
What is different between a Resolve analytical and a Reveal numerical model? Transfer fracture model from Resolve tight module to Reveal to back calculate geometry.

26. Reveal Oil Reservoir Model
Model variable compaction table, stress dependent perm and changing cleat compressibility
Pressure after one month

27. Effect of Cleat Compressibility
4.01
3.96
3.90
3.65
3.80
3.74
Effect of Cleat Compressibility
Porosity Reduction with Pressure
27/11/ /03/ /06/2014

28. Changing Oil Density over Time
41.5
40.4
39.3
38.2
37.1
36.0
Reduction of Oil Density over Time
12/12/ /01/ /06/2014

29. Reservoir Model - Conclusions
Porosity and compressibility have similar effects on BHP match
Changes on SRV affects the late match
Stress - Permeability function has an effect on the transient behaviour (early decline / build up)
BHP calculation need careful considerations due to the instability of low rate wells.
Stress dependent permeability needs to be included in the Reveal models to obtain a match

30. Thank you for your attention Questions?