Mixed Preformed Particle Gel System for Water Shutoff in Fractured Carbonate Reservoir

AbstractWater shutoff from production well using particle type material is a great challenge due to the complex pressure and flow distributions near wellbore. A mixed preformed particle gel (PPG) system was developed to enhance the performance for water shutoff in fractured carbonate reservoirs. The PPG blocking behaviors in fractures and methods to improve the water flush tolerance were investigated. PPG strength dominated the water shutoff performances in fractures. PPG with medium to high strength showed better performance than other samples due to the well-adjusted properties in blocking and flush tolerance. For the selected PPG, 30 mesh sample showed the best blocking performance among single mesh samples from 20 mesh to 80 mesh in the fractured artificial metal plug. Using 30 mesh sample as base sample, the 30 mesh and 40 mesh mixture with weight ratio 2:1 produced highest pressure build-up in two-size PPG mixtures. Further increasing the particle size distribution by combining various particle size PPGs, the blocking performance was improved. An optimized combination of 30 mesh, 40 mesh, 50 mesh and 60 mesh particles with weigh ratio of 4:2:1:0.25 was developed. In addition, a fiber material, added in the PPG, significantly improved the water flush tolerance of the PPG pack. A particle size combination of PPGs mixed with the fiber material generated better blocking performances than the other combinations. This study provides insights on packing behavior of deformable gel particles in fractures with a practical PPG based system for water shutoff treatments.