A sealing material is developed for refrac purposes. This material is liquid on surface, then hardens to form a plastic solid that creates a barrier across the legacy fracture pathways and perf openings.
The hardened material left in the wellbore was drilled out using a blade bit. After cleaning out past the top perforation cluster, the zone was pressure-tested up to the maximum allowable wellhead pressure, which translated to 5065 psi bottom hole differential pressure. After holding for 25 minutes, the pressure was released and drilling was resumed on the sealing material that covered the lower interval. Drill-out continued to a depth below the bottom depth of the lower perforation cluster. A subsequent pressure test yielded a differential pressure of 4976 psi. The material’s differential pressures measured in the field exceeded the results from laboratory testing. Drill cuttings confirmed that the sealing material had hardened downhole and this field test showed that the product can crosslink to form a solid barrier. Additionally, the material left in the wellbore was easily drilled out leaving a full-opening original casing ID. Some of the key factors that can enhance the performance of this sealing material is extensive laboratory testing, the use of diverters, appropriate downhole tool assemblies and squeeze methods; all of which help achieve full coverage of all the perforations.