High Temperature and High Pressure Sealing Performance Analysis and Optimization of Small Diameter Tubing Bridge Plug Rubber Tube

It is the key technology to reduce the pollution of production layer by using retrievable bridge plug to plug production string and carry out snubbing operation. This paper establishes the simulation calculation model of the small diameter bridge plug rubber tube through the rubber thermal aging experiment. The influence of rubber combination on sealing performance and safety under high temperature and high pressure was analyzed, and the rubber structure was optimized. The results show that the sealing performance of the three-rubber tube structure is about 8.7% higher than that of the double-rubber tube structure at 120 °C and 55 MPa. In order to take into account the deformation and sealing requirements of the rubber tube, the preset trapezoidal ring groove structure (groove number n, groove width l, groove depth δ) in the rubber tube is optimized. Under the condition of 35 MPa setting load, the optimized A-structure rubber tube (n = 3, l = 10.5 mm, δ = 0.5 mm) improves the sealing performance by about 21.15% and reduces the Mises stress by 4.88% compared with that before optimization. It is suitable for oil and gas wells with long-term sealing and high safety requirements. The sealing performance of the optimized B-structure rubber tube (n = 3, l = 10.5 mm, δ = 1.5 mm) can be improved by about 43.94%. Although the Mises stress is increased by 15.97%, it is still within the safe range and can be applied to the working conditions with high sealing pressure and short-term sealing.