System and method for re-fracturing multizone horizontal wellbores

A packer on a tubing string and diverting material pumped down the tubing string may be used isolate a fracture cluster in a multizone horizontal wellbore that has been previously hydraulically fractured. Once hydraulically isolated, fluid may be pumped down the tubing string to re-fracture the previously fractured fracture cluster in an effort to increase hydrocarbon production from the horizontal wellbore. The tubing string may include a testing device used to determine whether a specific fracture cluster within the horizontal wellbore should be re-fractured. Diverting material may be pumped down the tubing string and positioned adjacent a fracture cluster to hydraulically isolate the fracture cluster during the re-fracturing process. The diverting material may be cleaned out of the horizontal wellbore after all desired fracture clusters along the horizontal wellbore have been individually re-fractured.