Efficiently fracture treating a large number of zones has created a unique downhole tool challenge. In many applications, the operator requires a drillable cased-hole bridge/frac plug to effectively isolate multiple zones for stimulation in a single borehole. The main objective of the drillable plug is to isolate the lower zones so effective stimulation can be performed in the upper zones. This minimizes wellbore interventions while maximizing the number of zones stimulated. During drill-up, the plug must breakdown into small cuttings that can be easily transported utilizing conventional flow-rates to ensure a clean wellbore and unobstructed perforations. The plug must be composed of materials that allow for rapid drill-out using standard downhole motors and milling equipment.
Drillable plugs have evolved due to multiple challenges associated with the escalating number of zones that must be treated. Most recently, the service industry has produced a variety of composite bridge/frac plugs that have advanced performance compared to standard cast iron versions. However operators have experienced multiple problems with composite plugs.
To addresses the issues, a plug was designed and manufactured from precision aluminum alloy. The aluminum plug technology (APT) has significantly increased plug life-span having successfully addressed degradation issues in the application's pressure/temperature range. The new plug stays locked downhole under extreme temperatures/pressures without degradation and a unique anchoring system eliminates spinning of multiple plugs during drill-out. Advanced materials and a compact design have reduced drill-out time to an average of 20 minutes, saving the operator expensive rig time.
Using the APT, the operator has the option to flow back the well for an extended period before plug drill-out. APT has also drastically reduced the incidents of fishing due to partially set plugs. APT has demonstrated reliable performance during stimulation, effectively eliminating the adverse effects of plug movement during treatment.