18 Oilfield Review New Practices to Enhance Perforating Results Frederic Bruyere Total E&P UK plc Aberdeen, Scotland Dave Clark Gary Stirton CNR International Aberdeen, Scotland Aming Kusumadjaja Balikpapan, Indonesia Dasa Manalu Muhammad Sobirin Total E&P Indonésie Balikpapan, Indonesia Andy Martin Aberdeen, Scotland Derek I. Robertson BP Aberdeen, Scotland Alistair Stenhouse Consultant Aberdeen, Scotland For help in preparation of this article, thanks to Dave Atwood, Brenden Grove, Juliane Heiland and Ian Walton, Rosharon, Texas; Larry Behrmann, Kuala Lumpur, Maylasia; Alfredo Fayard, Houston, Texas; and John Wreford, BP, Aberdeen, Scotland. eFire, FIV (Formation Isolation Valve), HSD (High Shot Density), IRIS (Intelligent Remote Implementation System), OCD (Orientation Confirmation Device), OrientXact, PosiTrieve, PowerJet Omega, PURE, S.A.F.E. (Slapper- Actuated Firing Equipment) and SPAN (Schlumberger perforating analysis) are marks of Schlumberger. Recent developments in tools and techniques dramatically increase productivity and injectivity in perforated cased-hole well completions. These advances address a wide range of challenges from near-wellbore formation damage and perforation damage removal, to sand influx and safe, efficient wellsite operations. Perforating is a critical step in establishing connectivity between subsurface zones and wellbores that are completed with cemented steel casing. By understanding complex inter- actions between explosive shaped charges, charge carrier systems, a wellbore and the reservoir, and by applying customized perforating solutions, engineers can improve cased-hole well performance, optimize reservoir production and maximize hydrocarbon reserve recovery. To achieve these objectives, engineers now incorporate reservoir parameters and well- specific conditions into fit-for-purpose perforating designs. The results are proven processes and procedures that generate additional production revenue for operators. Recently introduced tools and techniques help operators increase productivity or injectivity, prevent sand production and improve the safety and efficiency of perforating operations. Deep-penetrating charges can bypass for- mation damage, increase the effective wellbore radius and reduce the need for additional perforating operations, acid washes or other perforation cleanup techniques. Recent advances in explosive shaped charges, charge manufac- turing and gun systems have yielded increases in perforation penetration of 20 to 30% even compared with the deep-penetrating charges that were introduced in the late 1990s and early 2000s. Perforating farther into a formation beyond near- wellbore damage caused by drilling or completion operations is one of the key factors in improving the productivity of cased-hole wells. Surge flow through perforations after shaped-charge detonation is critical in minimizing flow impairment and reduced conductivity caused by perforating-induced damage. Schlumberger researchers found that large-diameter, deep-penetrating, clean perfora- tion tunnels could be created by controlling the transient, or dynamic, pressure differentials that occur in a wellbore immediately after the detonation of perforating guns. An innovative design process and specialized systems exploit rapid changes in pressure that occur between perforating gun systems, a wellbore and a reservoir within a few hundred milliseconds after charge detonation. This dynamic under- balanced technique uses customized perforating designs, special shaped charges and fit-for-purpose gun configurations to generate a large transient underbalance from modest static underbalanced or overbalanced pressures.