Abstract
In order to solve the problem of conventional preformed particle gel (PPG) with relatively high cost and poor strength and shearing resistance, a preformed sawdust gel particle (S-PPG) with a more superior performance than PPG was presented. A series of S-PPG with different mass ratio of sawdust particles to gelling liquid were prepared with free radical polymerization. It makes acrylic acid and acrylamide as polymerization monomers, N, N '-methylene bisacrylamide as crosslinking agent, ammonium persulfate as initiator and sawdust particles as enhancer. In general, enhancer content was less than 1%, but the content of enhancer in this work was increased by about 20-30%. The microscopic morphology, swelling property, viscoelasticity, yield stress, creep-recovery characteristics and shearing resistance of S-PPG in the formation water had been studied. The plugging behavior of S-PPG was studied using core flooding test. The results indicated that the swelling ratio of S-PPG (1:5) in the formation water was 8. S-PPG showed better viscoelasticity properties, shearing resistance and higher yield stresses than PPG. Moreover, the plugging rate of the plugging system with 3000 mg/L S-PPG (1:5) improved from 85.1% to 90.5% in fracture core compared with PPG. S-PPG (1:3) improved the plugging rate from 85.1% to 91.9%. The research results provide an alternative plugging material in fractured reservoirs.
NSTL
Elsevier