Identification and classification prediction of fractured-vuggy reservoir type in carbonate rocks

In the evaluation of carbonate reservoirs, it is critical to identify and classify the reservoir types.The reservior types are determined by the storage space of reserviors.The storage space of a reservoir is dependent on primary pores generated by the diagenesis of sedimentary rock and secondary voids due to the transformation of the rocks at later supergene stage. Because of secondary transformation is highly variable, together with the alterations of the rock formations at different stages, the secondary pore structure of carbonate reservoirs is very complex, which causes the diversity of reservoir type. To solve this problem, based on the zoning of the carbonate rocks, well imagery and logging data, combined with coring, reservoir geology and testing data, this work attempts to identify reservoir types and categorize them by clustering analysis. The results suggest that the reservoirs in the study area include porous types, vuggy types, and fractured media types, which can be divided into four categories, serving as basis for carbonate reservoir evaluation.