Dynamic Characterization of Different Reservoir Types for a Fractured-Caved Carbonate Reservoir

Abstract Understanding reservoir types or reservoir patterns is critical for a successful development strategy decision in carbonate reservoirs. For the fractured-caved carbonate reservoirs in china, reservoir types are especially important because different reservoir types may apply different development strategies. This paper propose a systematic method of dynamic characterization on a carbonate reservoir in China. The proposed systematic dynamic characterization method mainly includes production data analysis and well test analysis, which combined with geological understanding. It is applied to the Ordovician fractured-caved carbonate reservoir in China, which has different reservoir types developed. Different reservoir types are classified and identified, and three of them are illustrated in detail. Based on the geological features of K fractured-caved carbonate reservoir in China, forward modeling method is firstly used for identification type curve generation of different reservoir types. Different numerical reservoir models are built, and the type curve of well test and rate transient analysis are generated. And the results are used for the actual reservoir type identification. Then combined with geological understanding, reservoir properties and reservoir types are evaluated based the dynamic methods, which include well test analysis and rate transient analysis method. Three reservoir types, which include volumetric caved reservoir, fractured reservoir, fractured-vuggy reservoir, are characterized based on the proposed methods and presented in detail. More than one hundred of reservoirs are evaluated. It is found that OOIP of most reservoirs are lower than 200 thousand cubic meters, and skin factor of most wells are lower than zero. The understanding of reservoir types and dynamic characterization results are much valuable for the next development options decision, which are applied to the K fractured-caved carbonate reservoir with successful results.