In this paper the results of a reservoir evaluation study of the Bahar Field, one of the most important oil and gas fields in the Azerbaijanian sector of the Caspian Sea are presented. The study has concentrated on the most important reservoir sections, Balakhany X and Pereriv Suite, encompassing (i) sedimentological and stratigraphic interpretation, (ii) petrophysical analysis, (iii) structural interpretation, (iv) assessment of hydrocarbon distribution, (v) geochemical characterization of the hydrocarbons, (vi) assessment of reservoir compartmentalization, (vii) establishment of static and dynamic reservoir models in digital format, as a basis for calculating in-place resources and assessing the potential for improved oil recovery. The study has provided new and detailed insight into the reservoir architecture and properties of the Bahar Field. In a broader context this detailed information and data analysis is believed to provide an improved basis for evaluating other tested and untested structures in this prolific hydrocarbon province.

An unconventional thin-bed analysis based on logs, core and miniperm data was needed to calculate the petrophysical properties of a reservoir under development in the Norwegian Sea. More than half of the reservoir section under investigation is composed of heterolithic facies: thinly interbedded sandstone and mudstone layers from one to several centimeters in thickness and of variable quality. By using miniperm measurements with 1-cm spacing on slabbed core, it was possible to resolve the properties of the rock far below the vertical resolution of conventional wireline logs and relate them to the bulk log measurements, P. 815

An unconventional thin-bed analysis based on logs, core, and miniperm data was needed to calculate the petrophysical properties of a reservoir under development in the Norwegian Sea. More than half of the reservoir section under investigation is composed of heterolithic facies: thinly interbedded sandstone and mudstone layers from one to several centimeters in thickness and of variable quality. By using miniperm measurements with 1-cm spacing on slabbed core, it was possible to resolve the properties of the rock far below the vertical resolution of conventional wireline logs and relate them to the bulk log measurements. Fig. 1-Core photographs showing sand-rich "light… and mudrich "dark… layers, interbedded at the centimeter scale, in a heterolith from the Heidrun Åre bayfill section. The left set was taken under white light; the right was taken under UV light.