Full-field numerical pressure diffusion model of UTRM:
| Input | Output |
|---|---|
Geological model |
and assumptions
| full-field saturation is not changing over time |
| full-field temperature is not changing over time |
Motivation
Dynamic Model History Matching (DM HM) is a routine process of reservoir flow simulations with numerous iterations and high uncertainty at each iteration on which model realisation to choose to improve the match.
In 3D or even in 2D mode the DM HM represent a very tedious procedure of very slow simulation runs.
The DM HM process is usually matches the production rates, formation pressure with account of available information on production allocation from each reservoir in multi-layer reservoirs.
Adding more inputs is not going to help with choice but will increase the time and complicates the already complicated task.
There is a clear need to simplify and accelerate the future DM HM exercises.
This can be achieved by calibrating some model properties in a separate optimisation loop preceding the final DM HM process.
This normally covers the model properties which drive pressure response to flow variations, such as drainage volume, transmissibility and boundary type/proximity.
The Cross-well Pressure Modelling (XPM) is a numerical pressure simulation procedure which assumes that reservoir saturation and temperature are not changing over time.
It can verify some model properties by matching the Unit-rate Transient Responses (UTR) which are normally retrieved from pressure deconvolution of PDG history records and/or from pressure interference testing.
Goals
| Check if available UTR are honoured by UTRM based on the current DM "as is" |
| Calibrate DM properties to achieve fair match between UTRM and available data on UTR |
Objectives
| Calibrate DM drainage volumes |
| Calibrate DM boundary type (sealing or constant pressure) |
| Calibrate DM fault system (faults extensions and conductivity) |
| Calibrate DM dynamic permeability ( absolute value and possible anisotropy ) |
| Calibrate DM formation thickness |
Workflow
| 1 | Add actual wells into XPM |
| 2 | For each well upload the drilled and startup formation pressure and Source BHPs (whatever is available) |
| 3 | For each well upload UTRM data (one single well DTR and all 2-wells CTR) and call it Source UTRM |
| 4 | In original DM model identify the locations of representative reservoir properties and sample them as phantom wells |
| 5 | Input the phantom wells intoXPM |
| 6 | Create the Delaunay grid in XPM (see Fig. 1) |
| 7 | Test #1 = Base Scenario |
| 8 | Propagate original DM reservoir properties throughout UTRM grid |
| 9 | Perform Test #1 pressure simulations |
| 10 | Print out the comparison of Test #1 UTRM against Source UTRM |
| 11 | Print out the comparison of Test #1 BHPs against Source BHPs |
| 12 | Test #2 = UTR Calibrated Scenario |
| 13 | Adjust the UTRM volume to match all UTRM LTR |
| 14 | Identify the phantom wells in cross-well intervals for future calibration |
| 15 | Adjust permeabilities and faults extension/conductivity to match MTR / LTR of Source UTRM |
| 16 | Print out the comparison of Test #2 UTRM against Source UTRM |
| 17 | Print out the comparison of Test #2 BHPs against Source BHPs |
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| Fig. 1. Example of Delaunay grid in XPM | Fig. 2. Example of matching diagram of simulated UTRM against Source UTRM. |
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Field Study & Modelling / Reservoir Flow Simulation
[ Unit-rate Transient Response Matrix (UTRM) ]
[ Pressure Testing ] [ Basic reservoir properties ] [ Complex reservoir properties ]