Perforating laboratory experiments are being conducted more frequently in recent years. In some instances, the goal is to qualitatively compare multiple candidate perforating techniques. In others, the goal is to obtain quantitative insight into likely flow performance in the field. Although the laboratory will never perfectly replicate the downhole environment, it can yield useful results which – if properly interpreted – can enable informed prediction of downhole flow performance.

A traditional flow lab experiment (along the lines of API RP-19B Section 4) yields many key results, four of which are required inputs to downhole inflow simulators. These are perforation tunnel length and diameter, and crushed zone thickness and permeability. In the case of natural completions, these parameters (in addition to other system and wellbore parameters), dictate the skin and ultimate flow performance of the completion.

Crushed zone permeability is typically inferred from core flow efficiency (CFE) and an assumed crushed zone thickness. As traditionally applied, this technique can yield values which are not accurate, and more significantly can produce misleading predictions of downhole performance.

To address this, we have developed new methods for both measuring and interpreting CFE. The new measurement technique yields CFE values which are more meaningful and relevant. The new interpretation technique provides a consistent method of translating CFE to crushed zone permeability, and is capable of accounting for the effect of partially plugged tunnels. This work clarifies and improves the link between lab and field performance of perforators, with the ultimate goal of increasing the value of downhole inflow performance predictions.

While other work is ongoing to challenge the framework of the conventional skin models, the present paper accepts these models as a premise. This work simply presents a coherent methodology of interpreting laboratory data, with the intent of generating the required inputs for skin models as they currently are. Furthermore, it is recommended that this workflow be considered for inclusion in any revisions to Section 4 testing protocol.

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