Abstract: As a kind of applied technology for special reservoir development, the secondary sand fracturing is of obvious advantage in shaping short and wide fracture and avoiding fracture penetrating interlayer, which has been successfully applied in fields. However, for the lack of relevant theoretical research, the field design of it is still in great blindness. This paper presents the fracture-extending model for secondary sand fracturing considering the impact of sand bank height change with time on fluid pressure drop; the proppant sedimentation and migration model considering the proppant convection impact, by which the proppant migration and distribution is gained by interface tracing; and proposes related program for correlation and analysis of fracture parameters from both secondary sand fracturing and conventional fracturing. The calculated results indicate that the secondary san fracturing is characterized by decreases of the length and height, and obvious increases of the width and conductivity of proppant fractures. According to the real reservoir petrophysical properties, the optimized secondary sand fracturing technology has satisfactory effect for stimulation, being worthy of popularization and application.

Key words: secondary sand fracturing, refracturing, fractural shape, proppant, migration