The use of ball drop type fracturing tools has been instrumental in the increase of activity in hydrocarbon-bearing reservoirs. These systems rely upon a series of balls that increase in size to progressively isolate stimulated intervals from toe to heel. It is of extreme importance to predict the behavior of such balls as they are pumped into the flow stream and ultimately the completion to avoid undesirable over-flushing of the fracturing stage.

In order to better understand the dynamics of launching these balls, a full scale surface test was performed on a flow loop. Using a ball launching device, balls ranging in size from .795" to 3.0" and composed of magnesium, aluminum, or ceramic material were introduced into flow streams of varying rates. The flow rates were designed to mimic both the flow rate through the ball launching device and the total flow rate after rejoining the treatment line. Various conditions were simulated including competing rates as the balls traveled through a simulated treating line and standpipe.

Computer modeling was utilized to further understand the behavior of fracturing balls displaced by fluid in horizontal multistage completions. The change in fluid velocity through the balls seats was studied to simulate the pump rate necessary for a ball to travel through the completion and land on the intended seat to provide isolation.

The information gathered during this experiment was analyzed to determine optimum flow conditions required to successfully launch fracturing balls. The effect of the ball size and material was studied to determine what influence they had on the ability of the balls to travel with the fluid. Recommendations on minimum rate versus ball size will be presented for both surface and down-hole scenarios.

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