Study on the Sealing Characteristics of Temporary Plugging Agent in the Perforation Tunnel

To understand the sealing characteristics of temporary plugging agents (TPA) in the borehole, a system was established for simulating high pressure temporary plugging experiments. The influence of the type and the concentration of TPA, the carrying liquid viscosity and the pump displacement on the sealing characteristics are studied, and the comparison and selection experiments of TPA are also performed. It can be concluded from experimental results that i) the higher viscosity of carrying liquid leads more TPA to going into the low-angle-borehole, resulting in better sealing characteristic; ii) the larger pump displacement causes more boreholes blocked by the TPA (especially the number of blocked low-angle-boreholes are more than that of blocked high-angle-boreholes); iii) both low-angle-borehole and high-angle-borehole are filled with more TPA duo to the higher concentration of TPA; iv) the sealing efficiency of TPA-knot is the highest, followed by TPA-particle and TPA-ball, and the TPA-fiber is the lowest. For obtaining the excellent sealing efficiency, it is recommended the mixed use of TPA-knot, TPA-particle and TPA-ball.