History Matching in Eclipse
Moderator: Simulation_team
Re: History Matching in Eclipse
Important to know which variables may have a significant effect on the history match and which may not.
Thus, at the beginning of the history matching process a sensitivity analysis of the key parameters is suggested.
Thus, at the beginning of the history matching process a sensitivity analysis of the key parameters is suggested.
Re: History Matching in Eclipse
Before starting to history match: define the data to be matched and the tolerances.
Final Match tolerances depend on:
- The study objectives
- The data quality
- The model coarseness
- Time and money available History
.
Final Match tolerances depend on:
- The study objectives
- The data quality
- The model coarseness
- Time and money available History
.
Re: History Matching in Eclipse
There are no “hard and fast” rules for history matching.
However, the following may be of some help:
- Keep it simple (KISS)
- Keep it physical
- Use common sense
- Don’t panic!
- Run model under voidage control until pressures matched, then switch to principal product rate
- Proper use of pseudos is more consistent than rock curves
- Correct the problem, not the symptom
- The most difficult problems may require a rethink of the base data
However, the following may be of some help:
- Keep it simple (KISS)
- Keep it physical
- Use common sense
- Don’t panic!
- Run model under voidage control until pressures matched, then switch to principal product rate
- Proper use of pseudos is more consistent than rock curves
- Correct the problem, not the symptom
- The most difficult problems may require a rethink of the base data
Re: History Matching in Eclipse
Pressure match
- Run the model under reservoir voidage control
- Examine the overall pressure levels, adjust the pore volume/aquifer properties to match overall pressure
- Match the well pressures, modify local PVs/aquifers to match overall pressures; modify local transmissibility to match pressure gradient
.
- Run the model under reservoir voidage control
- Examine the overall pressure levels, adjust the pore volume/aquifer properties to match overall pressure
- Match the well pressures, modify local PVs/aquifers to match overall pressures; modify local transmissibility to match pressure gradient
.
Re: History Matching in Eclipse
thanks alot sir very useful post for new beginners
Re: History Matching in Eclipse
engrsajid wrote:thanks alot sir very useful post for new beginners
Thanks sajid,
We will continue.....
Re: History Matching in Eclipse
Saturation match
- Normally attempted once pressures matched
- Most important parameters are rel. perm. curves and permeabilities
- Try to explain the reasons for the deviations and act accordingly
- Changes to rel. perm. tables should affect the model globally
- Changes to permeabilities should have some physical justification
- Consider the use of well pseudos
- Assumed layer KH allocations may be incorrect (check PLTs, etc.)
.
- Normally attempted once pressures matched
- Most important parameters are rel. perm. curves and permeabilities
- Try to explain the reasons for the deviations and act accordingly
- Changes to rel. perm. tables should affect the model globally
- Changes to permeabilities should have some physical justification
- Consider the use of well pseudos
- Assumed layer KH allocations may be incorrect (check PLTs, etc.)
.
Re: History Matching in Eclipse
Well PI match
- Not usually matched until pressures and saturations are matched, unless BHP affects production rates
- Must be matched before using model in prediction mode
- Match FBHP data by modifying KH, skin or PI directly
- Not usually matched until pressures and saturations are matched, unless BHP affects production rates
- Must be matched before using model in prediction mode
- Match FBHP data by modifying KH, skin or PI directly
Re: History Matching in Eclipse
Automatic history matching does not exist. New Eclipse SimOpt program is a history matching aid.
Try to minimize an objective function over the time period of the history:
Try to minimize an objective function over the time period of the history:
Re: History Matching in Eclipse
History Matching Adjustments
Simulation field pressure too high
Possible Changes
Pore Volume?
Aquifer?
Oil Initially in Place
(Contacts, So)
Energy?
Gas cap size
..
Simulation field pressure too high
Possible Changes
Pore Volume?
Aquifer?
Oil Initially in Place
(Contacts, So)
Energy?
Gas cap size
..
Re: History Matching in Eclipse
Break Through: OK, After BT WC too high
Possible Changes
Krw / Kro ratio decrease?
Aquifer size?
..
Possible Changes
Krw / Kro ratio decrease?
Aquifer size?
..
Re: History Matching in Eclipse
Water BT too early, After BT slope - OK
Possible Changes
Effective end point Krw ?
Horiz. Permeability of well to aquifer layer?
Shale or barrier between wells and water?
Vertical permeability between wells and water?
Numerical dispersion / grid effect?
..
Possible Changes
Effective end point Krw ?
Horiz. Permeability of well to aquifer layer?
Shale or barrier between wells and water?
Vertical permeability between wells and water?
Numerical dispersion / grid effect?
..
Re: History Matching in Eclipse
Gas BT simulation very late, After BT slope OK
Possible Changes
Effective Krg end point?
Shale or barrier effecting coning?
Vertical permeability between wells and gas?
Numerical dispersion / grid effect?
..
Possible Changes
Effective Krg end point?
Shale or barrier effecting coning?
Vertical permeability between wells and gas?
Numerical dispersion / grid effect?
..
Re: History Matching in Eclipse
Gas BT OK, After BT simulation slope in error
Possible Changes
Krg / Kro ratio increase?
Supply of gas?
.
Possible Changes
Krg / Kro ratio increase?
Supply of gas?
.
Re: History Matching in Eclipse
Predictions
Most simulation models are used to produce production forecasts. Exact details of prediction cases depend on particular field, so difficult to generalize.
- During predictions, well rates usually controlled primarily by FTHP/FBHP
- Most simulators can model a wide variety of operating constraints
- Check that the transition from “history” to “prediction” is smooth
- Monitor carefully “automatic” workovers
- Take care when using the model to plan infill drilling
- Simulation model recoveries are usually optimistic
..
Most simulation models are used to produce production forecasts. Exact details of prediction cases depend on particular field, so difficult to generalize.
- During predictions, well rates usually controlled primarily by FTHP/FBHP
- Most simulators can model a wide variety of operating constraints
- Check that the transition from “history” to “prediction” is smooth
- Monitor carefully “automatic” workovers
- Take care when using the model to plan infill drilling
- Simulation model recoveries are usually optimistic
..