Experimental study of the plugging–matching relationship between elastic particles and formation pore throats

Abstract

Low-cost modified rubber powder DBR elastic particles with good temperature and salt resistance were selected to investigate the plugging–matching relationship between the elastic particles and formation pore throats. The elastic deformation coefficient of the particles was measured using a custom-built uniaxial compression experimental device. Based on the ideal model and arrangement of spherical particles, a calculation method for the pore throat size was determined according to the statistical results of pore size measurements in the simulated formations (sand packs). The injection properties of DBR particles with different diameters in different permeability simulated formations were studied using a sand-filled tube displacement device. Through comprehensive analysis, the injection pressure fluctuation frequency, injection surface filter cake situation, particle entry depth, and plugging pressure, it was found that the elastic particle plugging matching coefficient (defined as the particle to pore through diameter ratio) range was 0.21–1.10 at different particle injection concentration(≤5wt%), and it is further proposed that the matching coefficient for elastic particles can be converted to that for rigid particles by dividing through by the elastic deformation coefficient, which may prove useful in guiding profile control and water plugging operations in the field. Finally, the different stages in the plugging and migration mechanisms of elastic particles in formation pore throats were illustrated using a visual variable diameter tube model. The model clearly showed that particle backflow disturbance is an adverse factor affecting particle plugging.