Limited-Entry Frac Applications on Long Intervals of Highly Deviated or Horizontal Wells

Abstract

Abstract Long horizontal sections have been used increasingly in moderate-to low-permeability reservoirs. In these reservoirs, a successful program for applying fracture-stimulation treatments is a key component for commercial success. Historically, such wells have been stimulated with several separate fracture treatments, requiring expensive well operations between fracture stages. Successful zonal isolation for each fracture stage has been a primary reason for the success of this technique. This paper reports recent efforts by several operators to reduce completion costs by extending the application of limited-entry fracturing techniques to very long sections of highly deviated or horizontal wellbores, while ensuring effective fracture stimulation of each perforated section. Many special innovations have been introduced recently for enhancing the applicability of limited-entry fracturing in long, openhole completions and in some uncemented liner applications. Some of these methods have been published; other unpublished methods are presented in this paper. Case histories are presented for both sandstone and carbonate reservoir completions. Considerations that guided the wellbore azimuth, casing programs, perforating schemes, and fracturing program variables are presented. Known problems and unpredicted formation responses are also discussed.