The Benefits Blog Series: The Benefits of Reduced Horsepower and the SC Bowhead II Sliding Sleeve System
When addressing pumping horsepower requirements, the SC Bowhead II sliding sleeve system has an inherent advantage which can reduce costs. As it is Single-Point entry system, the stimulation is localized at one entry area into the formation and the pumping model can be designed and implemented with less horsepower and more efficiently than that required for stimulating multiple clusters simultaneously (as in PnP Limited Entry systems). Real time adjustments to the pumping program can also be achieved more effectively. As opposed to PnP completions, the operator knows that the entire stimulation was placed directly at the point of entry and there is no need for guess work as to how much stimulation went to various open perforations within a stage.
Pump rate and stimulation pressure are two critical components of any successful hydraulic fracturing treatment and both are directly related to pumping horsepower. In application, once the formation’s in situ stress is overcome and fracture initiation occurs, the pump rate must be sufficient to overcome the natural formation leak off rate just to hold the fracture open. Additional pump rate is then required to increase downhole pressure and facilitate further propagation of the fracture. Conventional fracture geometry models utilize pump rate as a variable and generally predict greater fracture length, height, and width with increased pump rates.
Studies have indicated that higher pump rates can also induce additional propagation at natural fracture interfaces within a wellbore. Thus increased pump rates tend to improve the overall fracture network efficiency within naturally fractured reservoirs. High horsepower demands are typically associated with PnP completions in order to generate very high pump rates. If one cluster initiates a fracture before the others, the pump rate must be increased just to initiate fractures at other cluster sites and then increased even further to hold multiple fractures open and further stimulate them simultaneously.
The SC Bowhead II system also offers a potential pumping advantage from a mechanical standpoint when compared to other Single-Point entry systems as it utilizes sleeve bores which are equivalent to casing drift ID prior to collet insertion. This provides an effective full bore flow area from the surface down to the opened sleeve at the point of formation stimulation. Ball Drop systems have graduated seat IDs which can act as downhole chokes and increase pumping friction during stimulation. Likewise coil activated systems require coiled tubing to remain in the hole during stimulation and the net pumping area is reduced to the net annular area between the outside of the coiled tubing and the inside of the casing. This creates friction pressure as opposed to the full bore casing bore feature of the SC Bowhead II.