Abstract

The use of hydrajetting for perforation of wells has been commonplace since the 1960s. During those early years, jetting success was consistently demonstrated. While the quality of hydrajetted perforations is admittedly better, they are generally costly to implement. Horsepower requirements and logistics are a few obstacles associated with this process in terms of cost reduction. With the birth of hydrajet-assisted fracturing (HJAF) methods in the last decade; however, these obstacles were immediately overcome when hydrajet perforating became an integral part of the stimulation process. Hence, the system quickly transposed into an effective, time-saving stimulation treatment method. Within a few years, another hydrajet perforating + frac stimulation process was developed, where coiled tubing (CT) was used for hydrajetting only, and afterward the frac stages were all pumped down the annulus of the CT and the casing, with sand plugs used to seal off after the fracture stimulation treatment to allow more stages of the "hydrajet perf + frac" applications up the well in either vertical or horizontal wells. Soon, an increased level of using hydrajet perforating as a stand-alone service also became far more common.

As these hydrajetting processes become increasingly popular, intensive studies are needed to continually improve the performance of the tools and processes. For example, increased proppant volumes combined with an increased number of fracture stages or more perforations to be placed in one trip quickly mandates creation of higher life-expectancy tools. Improving the performance requires improving the hydrajetting-technology knowledge; in addition, well completions often dictate the size limitation or design of the jetting tool itself, which in turn dictates the pumping limits of the job. Lastly, new jetting technologies might have to be created to define the optimal quality of proppant which should be used in oilfield applications.

This paper offers an in-depth study on improving our jetting expectancies and performances by knowing the various behaviors of abrasives or proppants when they are jetted through nozzles and under other conditions. This data will help us in optimizing the jetting process itself. Results of extensive laboratory tests on different types of proppant are presented which provides a much better understanding of the limitation of various proppant types. Knowing these limitations is a key to successfully using hydrajetting for stimulation purposes or maximizing hydrajet effectiveness when perforating or cutting. Examples of easy-to-use computational tools for such purposes are also presented.

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