A Petrophysical Procedure to Evaluate Permeability Behavior in Complex Reservoirs; Case Studies in IRAQI Oilfields

Abstract

Formation permeability is one important flow parameter associated with subsurface production and injection. Reliable Formation permeability values are often measured in laboratory from cores or evaluated from well test data. Well logs Derived Permeability are associated with high accuracy with NMR logging; However, NMR logging, core analysis and well test data are usually available for few wells / specified intervals in a field, while, almost all other wells are logged conventionally.The Procedure use Water Saturation and Effective Porosity Values as inputs; the Geological zonation is critical; each selected zone will be cross-plotted to evaluate the Irreducible water saturation factors then Archie's parameters for each level-by-level will evaluated using Gomes Iteration or Dialectic log method of Freeman et.al, afterward Pirson and Coates et al. methods will be utilized to calculate the reservoir permeability, these method improved to inclusive Archie's parameters, finally a Statistical convergence approach specifically Mean Absolute Error ЉMAEЉ method is utilize to validate the Results with other Permeability sources of Core, NMR and Pressure testing.Case Studies were selected from Super-Giant Oil Fields located in Middle and South of Iraq to test the model applicability, due to the availability of Pressure Testing, Core analysis, Dielectric log and NMR logging data in complex reservoirs of these field. key observations; There are no general Permeability model (equation) can characterize permeability even in subsequent formations and The Archie's Parameters have crucial effect on Permeability Values, the utilization of the proposed model have helped greatly to select the best-to-fit Permeability model for each Reservoir.There are several Permeability Models in lectures, the select of best-fitted-Model to a Reservoir was and will continue as a matter of discussion. The understand the permeability behavior is critical and in this study an Integrated Petrophysical Procedure (using the aid of Core Analysis, Crossplot and the computer iteration) was presented to select the best Permeability Model.The Novel significance of the proposed procedure were distinguished with its ease flexibility to include any other permeability model and it can be utilize in any other Oil Fields giving more understating to the permeability behavior in a selected reservoir.

Interpretation of Mud Losses in Carbonates Based on Cuttings Description, Well-Logging, Seismic and Coherency Data

“…in the Ahdab oil field based on the cutting descriptions from older wells. The formation can be split into two sections [6], the lower section is dominated by basinal, slope and foraminiferal bank deposits while the upper section with a fully developed rudist is dominated by a carbonate platform with lagoonal sediments. In this model, both the lower foraminifera pack/grain stone banks and rudist platform were topped by a 3 rd order regional sequence boundaries as presented in Fig.…”