A unique preformed particle gel with re-crosslinkable ability to re-form bulk gel for chemical enhanced oil recovery of void space conduits containing reservoir is described herein. The formation of the bulk gel was achieved by reversible ionic crosslinks of the preformed particle gels as induced by brine under reservoir conditions. The re-crosslinked hydrogel with ionic features showed rubber-like mechanical behaviors, a critical parameter of the particle gels to increase plugging efficiency. The re-crosslinking ability of the preformed particle gels under different salinity could be controlled by tuning the ionic interactions within the hydrogel. In addition, the long-term thermal stability of the re-crosslinked bulk gel has been demonstrated. Furthermore, the re-crosslinked bulk gels could significantly reduce permeability of large fractures as demonstrated by core flooding experiments compared with traditional preformed particle gels. The re-crosslinkable bulk gel with robust mechanical properties could offer the candidate to block void space conduits containing reservoirs for enhanced oil recovery. (C) 2017 Elsevier B.V. All rights reserved.