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7th Middle East Geosciences Conference and Exhibition
Manama, Bahrain
March 27-29, 2006
Analysis
in Thamama and Shuaiba
Formations
1 Petroleum Development Department (PDD), Abu Dhabi
Company For Onshore Oil Operations (ADCO), Abu-Dhabi, United Arab Emirates, phone: +971 50 6140992,
[email protected]
2 Schlumberger, 200 Gillingham Lane, Sugarland, TX 77478
3 Schlumberger, Ridgefield, CT
Data from eight wells in four Abu-Dhabi on-shore fields were gathered and interpreted.
The objective was to evaluate a new methodology for porosity and permeability analysis
in Carbonates with Inter-granular
and Macro porosity. This methodology uses NMR
log
data, and electrical image data when available, to partition porosity
into micro, meso and macro components - and then uses that partition to reconstruct the permeability and do a facies
analysis
.
The results of the interpretation were validated against core plug permeability and a traditional Reservoir Rock Type classification.
The main conclusions are: ·The methodology and its underlying model of pore-to-pore connectivity is widely applicable to
Carbonate formations such as the Thamama and Shuaiba reservoirs. ·The methodology can be applied without whole core.
We established optimum formation specific parameter values which give reasonable results when compared with results
obtained by using parameters that best fit core data on a well
-by-
well
basis. The interpretation results are therefore
reasonably analyst-independent. ·Spot measurements of permeability or mobility, from formation test data or sidewall
coring, are strongly encouraged to validate the results. ·When available, electrical image data help identifying and
quantifying the Macro porous zones. ·NMR logs respond to both the pore size and to oil properties. In one
well
the oil signal
dominated and it was not possible to compute an accurate permeability. ·The
log
derived facies correlate with the broad
features of the traditional Reservoir Rock Type definition. This is encouraging, even though more work is needed there.