Engineered Perforating Charges Designed for Stimulation

Abstract

Abstract Hydraulic fracturing is recognized as a successful stimulation technique used to enhance recovery from reservoirs. Prediction of fracture initiation and propagation from wellbores is necessary for efficient hydraulic fracturing stimulation tasks. Perforating is key to the success of a hydraulic fracturing treatment; it provides a means of communication between the wellbore and reservoir. Additionally, in a fracture-stimulated reservoir, the perforations serve as fluid conduits between the fracture and wellbore. Once the fracture is created, perforations provide the entrance to the fracture for the proppant. The perforation diameter must be sufficient to help prevent bridging because an accumulation of proppant can block the entrance hole. Inadequate perforations, low perforating efficiency, and variations in perforation entrance hole diameter can increase the effects of near wellbore (NWB) tortuosity and leave several holes that do not contribute to stimulation, causing uneven treatment distribution, increased formation breakdown pressure, and suboptimal completion—occasionally beyond the pressure capability of the surface equipment or design rating of the well. A new class of shaped charges engineered to maximize hole diameter while maintaining a consistent exit hole diameter independent of well profile and/or gun eccentricity has recently been introduced for unconventional resources requiring stimulation. Designed for perforating before a hydraulic stimulation, these new charges can help reduce the probability of screenout during the fracturing process. This paper describes the new charge technology in detail and addresses its successful deployment during fracturing of tight gas wells in Saudi Arabia. Specific examples are used to illustrate how the system facilitates prefracture evaluation, fracture initiation, and how fracture tortuosity and perforation friction entry values are decreased compared to previous perforating systems.