Carbonate reservoirs hold more than 60% of the world's total remaining oil and 40% of gas reserves (Schlumberger, 2007). With recovery factor averaging around 25–30%, these reservoirs still have substantial amount of trapped hydrocarbons. The primary reason for this poor exploitation of reserves in carbonate stems from the fact that it is challenging to characterize storage and flow properties in these reservoir. Carbonate rocks are known to exhibit depositional and developmental processes (EOR flooding) related heterogeneity. Diagenetic processes like dissolution and precipitation in presence of certain fluid types such as: brine, may have drastic effects on the matrix properties (Eberli, 2003). Diagenesis can trigger heterogeneous distribution of petrophysical properties that may lead to heterogeneous saturation and elastic property distribution. We present our analysis on sensitivity of heterogeneity in carbonate fabric to time-lapse flow and elastic properties variation. We found that at full (end point) saturation, the most heterogeneous sample imbibed 20% less brine than the least heterogeneous sample. Also, at full saturation, the least heterogeneous sample showed 45% more increase in normalized bulk modulus and 10% more decrease in normalized shear modulus than the most heterogeneous sample. Finally comparing our measurements and Gassmann predictions, it seems that these carbonates mainly exhibit patchy saturation.

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