Abstract

Improved oil recovery is more sensitive to sub-log scale heterogeneity than primary recovery processes. Determination of porosity, net-to-gross, saturation and permeability, both magnitude and direction, at scales below log resolution is often required in secondary and tertiary processes and can have an impact on the estimation of original hydrocarbon in place, by-passed oil and recovery factors.

Conventional log interpretation and conventional static modeling workflows may not capture sub-scale log heterogeneities, often due to the averaging involved in the upscaling process. Even though log values have been generally calibrated to plug scale (cm3) measurements, they are averaged over volumes much larger than their scale(s) of key heterogeneity.

This paper compares the simulated response derived from conventional and from effective property and lamina-scale modeling in three different oil bearing formations in the Argentinian Neuquen Basin, namely Quintuco, Sierras Blancas and Lotena Formations. All three Formations are candidates for waterflood developments and enhanced recovery processes options are being examined.

Permeability, porosity, saturation and net-to-gross ratio were determined by constructing high resolution models that enabled capturing sub-log scale heterogeneities. These models were subsequently upscaled at representative elementary volumes and the derived effective properties were used in building simulation models through different upscaling methodologies.

Results of the two scale models for each reservoir are compared. Strengths and weakness of the applied methodology, as applied to these specific cases, are evaluated and discussed.

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