Flow tests conducted on standard cylindrical Berea targets are used to evaluate the relative merits of jet perforators. The procedure and equipment for the flow tests are described in the API Recommended Practices 19B revised recently. The performance of the perforators is quantified in terms of core flow efficiency (CFE).

The CFE is the ratio of the actual post-perforation flow rate measured on the core to the theoretical ideal flow rate calculated from the mathematical models considering post-perforation flow geometry. The post-perforation flow tests may be conducted in several different flow geometries; axial flow, semi-radial flow, and radial-axial flow.

This study presents analytical solutions to predict the ideal rates for the complicated post-perforation flow configurations. The proposed solutions are compared against the existing numerical models and verified. The analytical solutions are general, and very fast and inexpensive to compute.

After verifying their accuracy, we use the solutions to evaluate the validity of the API recommended procedure and analysis technique. We demonstrate that the post-perforation flow geometry, core/perforation dimensions, permeability anisotropy, and the degree of formation damage control CFE. The same degree of formation damage yields different CFE in different post-perforation flow geometries. Finally we introduce a method to convert the CFE data to an equivalent skin factor for the perforated wells.

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