Development of New Family of Perforating Charges for Stressed Rock Following a New Industry Standard

Abstract

Executive Summary We describe the development of a new perforating charge, and its ultimate qualification following a recently-released industry standard testing protocol. The updated RP19B Section 2 standard program (API, 2021) prescribes a total of 12 tests, wherein commercial batch perforators are shot into natural sandstone targets across a range of in-situ stress levels. Testing included rigorous preparation and documentation, and was third-party witnessed for full transparency. Compared to a reference legacy charge (which had been originally qualified in a 19B Section 1 unstressed concrete target), the new charge improves penetration performance in the standard stressed rock target by up to 22%, while simultaneously increasing casing hole diameter by 32%. The industry has increasingly recognized in recent years that charge performance in unstressed concrete does not reliably correlate to performance in stressed rock. This suggests that at least some concrete-optimized charges may not deliver optimal performance downhole. Therefore, the incorporation of a standard stressed rock target to charge development should lead to perforators better optimized for downhole environments, compared to charges optimized for unstressed concrete. Independent witnessing further increases confidence in the performance to be expected in actual wells. Improved charge performance downhole, in turn, should translate directly to more productive wells (or, in the case of injectors, wells with better injectivity). The charge discussed in this paper is applicable to two common gun sizes – namely 4-5/8 (or 4-1/2) in, loaded at 5SPF, and 7-in (12SPF). As of this writing, the same methodology is currently being applied to the development of additional charges for other gun sizes, ranging from 2 to 7 inches.