The search for the optimum stimulation method for unconventional/tight reservoirs (UTR) in the US has been the object of study of many papers due to increased activity in these hydrocarbon plays and the potential rewards to finding the ideal method. Rock heterogeneity, water zone proximity, stimulation design, and completion methods have a significant influence on the final outcome and add complexity to the quest. This paper describes a novel alternative to conventional stimulation methods in UTR. The document compares a well fractured using the traditional plug-and-perforate (PnP) method and a well fractured down the coiled tubing-casing annulus using Coiled Tubing-enabled fracturing sleeves (CTFS) with an equivalent stimulation treatment, both in a cemented application. CTFS are pressure-balanced fracturing sleeves that are hydraulically activated through a pressure differential induced by setting a coiled tubing-conveyed isolation packer in the sleeves. The CTFS are novel as they do not rely on composite plugs, ball-drop systems or darts to operate and therefore leave a full-bore internal diameter after the treatment has been completed.

A complete approach to the technology application is described as similarities and differences in drilling practices, cementing techniques, completion methods, and – more importantly – production results are highlighted. As a challenging application in a well with a measured depth over 18,000 feet, pre-job preparation and diagnostics are discussed. Challenges encountered and lessons learned throughout the study are included.

The comparison shows how the use of targeted fracturing with CTFS yielded a significant production increase over an offset well that was conventionally treated. Similarly, the positive effects of these results over the estimated ultimate recovery (EUR) figures are discussed. Production tests and tracer data are used to support field data.

The results have practical and significant application in emerging and established unconventional reservoirs, as it provides a targeted alternative with increased production results to PnP’s traditional "blanket" fracturing approach of stimulating multiple clusters at a time. Over the mid-to-long term, these results can potentially lead to operator financial savings/efficiencies by modifying drilling programs to drill fewer wells while achieving similar returns on reserves – an advantage during slow times – or drilling the same number of wells for increased returns of reserves.

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