The synergistic mechanisms of fracture plugging in tight reservoirs with different lithologies: An experimental investigation

Abstract

A temporary plugging fracturing (TPF) experimental apparatus was independently developed to systematically investigate the synergistic mechanisms of fracture plugging in tight reservoirs with different lithologies. The primary force chain structure is established through particulate bridging from CT scanning of the temporary plugging barrier (TPB) during TPB formation. The network formation of bonded fibers continuously captures particulates and powders, and the powders fill the gaps between particulates to reduce TPB leak-off. The addition of 1 % wt fiber reduces the number of TPB breakthroughs and diverter usage. The “particulate + powder” (PP) diverters formulation accelerates the plugging speed of conglomerate fractures by 10 %-30 % compared to sandstone and 20 %-37 % compared to volcanic rock, particularly in fractures exceeding 2 mm in width. The more obvious synergistic bridging effect of fibers and particulates causes the percentage of fiber and particulates to be more than 80 % with the addition of fibers to the diverter fluids. Fibers can replace some of the particulates in the formation of the TPB with the percentage of particulates of different mesh in the TPB is reduced from 80 % to no more than 55 %. In field construction scenarios, it is recommended to use the PPF diverter formulation for volcanic rock fractures, and PP diverter formulation for small sandstone fractures, and PPF diverter formulation for large sandstone fractures, and the PP diverter formulation for conglomerate fractures. These research findings provide theoretical guidance for designing TPF construction strategies tailored.