An Evaluation of Various Perforating Designs Performance in Reducing Near Wellbore Friction during Fracturing

Abstract

Abstract: Establishing connectivity with the reservoir in a cased-hole cemented completion is a crucial parameter for the success of fracturing operations. Numerous fracture stimulation treatments have failed due to the failure to initiate the fracture or to place enough proppant along the hydraulically created fracture due to an early screen-out caused by improper perforating design. This problem becomes more significant in the case of unconventional resources exploration and development as these resources inherently require a high treatment pressure coupled with a high fracturing gradient. Therefore, a well-engineered perforating design is regarded as the first challenge to be overcome to ensure the success of a fracturing treatment. This paper presents a comparative study among different perforating guns by different service providers with different sizes in terms of reducing the near-wellbore pressure loss during fracturing treatment. Moreover, various design parameters such as perforation phasing, density and perforating interval were evaluated for several gas wells completed with proponent fracture in a giant field in Saudi Arabia. The comparison is based upon analyzing the step-down rate tests and quantifying the contribution of pressure loss due to entry friction to the total friction during the stimulation. The magnitude of the treating pressure for various designs during the main fracturing treatments was also examined. Reservoirs investigated include tight sand and unconventional gas bearing formations. Different techniques to mitigate or reduce excessive near-wellbore friction are also presented.