Fracturing Bypassed Pay in Tubingless Completions

Abstract Intervals with marginal production potential are often bypassed during the early stages of reservoir development. As existing reservoirs mature, production from these bypassed intervals offer a more economical alternative for production enhancement over either in-fill or re-drilling operations. Effective fracture stimulation of such payzones using conventional techniques can be limited by a variety of operational and economical considerations. The integration of coiled tubing operations with hydraulic fracturing procedures overcomes many of the constraints associated with the stimulation of bypassed payzones. Specialized bottomhole assemblies are used to isolate existing perforations. A high pressure coiled tubing workstring transports the fluid and proppant system. The coiled tubing also protects the existing well tubulars from the high pressures experienced during fracture stimulation. A viscoelastic fracturing fluid is preferred over conventional polymeric fluids. This fluid exhibits significantly reduced frictional pressures and hence achieves the desired injection rates under such pressure-constrained conditions. This paper describes the operational and design aspects of the coiled tubing fracturing procedure. A field case study is finally presented to demonstrate the economical benefits realized by this methodology.