Multistage hydraulic fracturing is necessary for economically efficient gas production in low-permeability shale resources.Completion devices such as fracturing balls and ball seats are often used for downhole fluid and pressure control.To continue production,these devices must be eliminated by methods such as milling,or they must be flowed back to surface.Traditional frac ball materials are low strength and severely deform,leading to costly intervention operations and higher operational inefficiency.In addition, it is believed that smaller fracturing balls from the toe section do not flow back to surface,potentially creating restrictions in the flow path. This paper presents a newly developed disintegrable nano-engineered composite(DNEC)and its use as frac balls,in a multistage hydraulic fracturing system.The historic operational data of successful multistage hydraulically fractured wells and the testing data of the disintegrable DNEC frac ball in various oilfield hydraulic fracturing applications are presented.Furthermore,the material selection guidelines of various DNEC grades for and different well conditions are discussed. DNEC is used to increase fracturing operation efficiency and ensure zero loss of producing stages due to fluid block,by a ball stuck on a ball seat,from differential pressures.DNEC can achieve greater than three times the strength of its base material leading to a high-pressure rated(10,000 psi)hydraulic fracturing system The material properties can be engineered at the nano level to encompass a wide range of disintegration rates.DNEC-based completion tools eliminate the need for intervention and enhance well productivity by ensuring an open flow path.As of the end of 2013,over 20,000 frac balls utilizing this technology have been successfully deployed for use in multistage fracturing systems in gas/oil wells.
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