Experimental work to determine the effect of load pressure on the gel pack permeability of strong and weak preformed particle gels

Preformed particle gels (PPGs) have been widely applied to reduce the permeability of super-high permeability streaks/fractures. PPGs have an ability to decrease water production and increase sweep efficiency in mature oilfields. Either the success or failure of a PPG treatment depends largely on whether or not PPGs can effectively reduce the permeability of the fluid channels to an anticipated level. This work sought to investigate the influence of several factors on PPG blocking efficiency. A filtration model was designed to determine the permeability of PPGs packed in channels/fractures. Two types of PPGs were used for these filtration experiments: Daqing (DQ) and LiquiBlock (TM) 40 K. Particle sizes fell between 30 and 120 meshes. Results indicate PPG permeability decreased as load pressure increased. Additionally, PPGs with a larger particle size exhibited higher PPG pack permeability than PPGs with a smaller particle size. The PPG permeability with a lower brine concentration was more than the PPG pack permeability with a higher brine concentration when the PPG pack was not compressed by a piston. However, PPG pack permeability was less when using a lower brine concentration whether the PPG pack was compressed because the PPGs with higher brine concentration loss more water than the PPGs with the lower brine concentrations. According to our paper results the optimum gel pack with a preferred permeability can be designed by the right selection of the gel strength and correct particle size at reservoir pressure. (C) 2016 Elsevier Ltd. All rights reserved.