Impact of Perforation Variables on Well Productivity at Prudhoe Bay

Abstract

ABSTRACT Numerical models and laboratory studies have been performed by other investigators to define the impact of various perforation parameters on well productivity. Field verification of these findings is difficult due to uncontrolled factors such as charge performance, drilling invasion, and reservoir quality. Using information from Prudhoe Bay, a study of perforation parameters affecting well productivity was undertaken in an effort to identify the most significant perforation variables in terms of initial and long term well performance. Findings from the study of field data verifies that perforation penetration is the most significant factor affecting well performance. Wells perforated with deep penetrating casing guns have lower drawdowns and significantly lower decline rates than wells perforated with through tubing guns. The high decline rates at Prudhoe Bay are a result of calcium carbonate scale buildup, which is exacerbated by perforations of poor quality. The data also suggests that 0° gun phasing is comparable to other phasing when perforating in deviated, large diameter well bores.