The Movement and Force Analysis of Temporary Plugging Ball for Perforated Holes in Directional Well

For wells that have been perforated, layered or segmented stimulation is an effective way to increase the reservoir production and improve the production profile. Ball-sealing is one of the most economical, simple and effective ways. With the rise of unconventional oil and gas development, the demand for intensive cutting, fine fracturing and refracturing is becoming more and more urgent. And the research on temporary plugging fracturing technology in the wellbore has become a hot and difficult point. In order to improve the plugging efficiency of the temporary plugging ball in the directional well, the movement stages of the temporary plugging ball in directional wellbore are divided. It consists of the carrying acceleration stage, the gravity acceleration stage and the constant velocity movement stage. The force on temporary blocking ball was analyzed. The equations of inertial force, drag force, ball holding force and escape force that determine whether the temporary blocking ball is blocked or not are given, as well as the comparison and judgment conditions. Through calculation and comparison, the sensitivity of pumping rate, density difference, number of plugged holes, fluid viscosity on the plugging efficiency of the temporary plugging ball is analyzed. It is found that the pumping rate and the number of perforated holes have a greater impact on the plugging efficiency. Higher pumping rate, fewer holes and lower density differences are beneficial to improve the success rate of plugging.