Kent Folse

Perforating System Selection for Optimum Well Inflow Performance

Oilfield operators and service companies continually are faced with challenges to provide completions that not only produce at optimum levels but also accelerate return on investment (ROI). The operational demands faced today are further complicated by a rapid expansion of the range of reservoir scenarios. When attempting to find methods to accomplish the above goals, the industry often overlooks one very important component of the completion processCperforation. In the energy industry, many companies base selection of shaped-charge perforators solely on API Section I criteria such as depth of penetration or casing-exit hole size. This paper is proposing that other factors, such as the actual performance of given shaped charges at in situ conditions, also should be evaluated when making perforating decisions for the completion process. Focusing perforator system performance on reservoir productivity rather than on the shaped-charge performance optimized for concrete testing (which is the case with API Section I) can ultimately lead to significant improvement in well-inflow performance. Although API RP43 Section IV perforating procedures (to evaluate well perforators under in-situ conditions) have existed since 1985, field validation of experimental results and model predictions based on these procedures has been limited. This paper will discuss insights gained from a series of Section IV tests conducted with Berea and Castlegate sandstone cores under varying in-situ conditions. The Section IV lab experiments represent physical models of the near-wellbore region during perforation and completion processes under in-situ stress. The results of these experiments indicate that understanding the inherent system inadequacies and experimental conditions is critical to proper integration of the results with theoretical models and field data.