Summary
Preformed-particle-gel (PPG) treatments have been successfully used in injection wells to reduce excessive water production from high-temperature, high-salinity fractured reservoirs. However, PPG itself cannot be used in fractured producers because it tends to wash out after the wells resume production. Therefore, we proposed to combine curable resin-coated particles (CRPs) with PPG to control water production from fractured producers. In this paper, millimeter-sized tubes and fractured carbonate cores were designed to comprehensively investigate water-plugging behaviors of the combined system under the conditions of various fracture parameters and PPG/CRP sizes. Particular attention was given to control the PPG washout after production was resumed. The results showed the cured CRPs could generate immobile packs in fractures and dramatically mitigate the PPG washout. The small size of the CRPs and the small ratio of CRP size to tube diameter contributed low permeability and homogeneity to CRP packs. Meanwhile, the less-permeable and more-homogeneous CRP pack, as well as the larger-sized PPGs, contributed to a higher PPG breakthrough pressure gradient. Moreover, some of the PPG particles blocked in the CRP packs could be released through high-speed brine injection from producers, which indicated the recoverability of the water plugging. This study provides a promising approach to reduce the high-water-cut problem in fractured producers.