This paper covers four case histories of refracturing technology applied to under-stimulated wells, along with the benefits and well economics of returning these older wells to profitable production. Refracturing candidate selection criteria, operational execution, and well results for the four full-lateral refracturing projects are discussed.
Refracturing candidate selection criteria were developed based on several parameters tied to improved production and project economics. Liner refrac methods were evaluated to select wells and field trials were performed to verify each method provided both ease of execution and isolation. Cemented liners and several expandable liner systems were evaluated. With effective mechanical isolation, highly effective modern frac designs can be applied successfully to refracs.
The refracturing candidate wells outperformed the expected type curve and yielded positive economics. One cemented liner refrac showed poor isolation during treatment. Expandable liners showed good isolation, but some expandable technologies were better than others were. Rigorous planning and engineering were considered crucial to ensure trouble-free operational execution and to deliver an optimum wellbore for refracturing purposes.
The criteria for refracs included in this paper are directly applicable for evaluating refrac candidates. The experience with isolation methods enables engineers to select the proper technology to seal old perforations.