Investigating the influence of operating variables on sealing performance of a V-ring seal stack in the oil and gas industry for enhanced environmental and operational performance

Static V-ring seals, essential components in oil and gas industry valves, have received limited attention compared to rotary and reciprocating seals in previous research. This study fills this gap by meticulously investigating the performance of these seals under conditions involving minimal or no rotational movement, offering valuable insights into their functional capabilities. The objectives of this experimental study are to develop an experimental setup mirroring industrial conditions to assess the performance of seals used in oil and gas valves. Accordingly, two fluorinated elastomer seals (AFLAS) and three Polytetrafluoroethylene (PTFE) seals were employed together as a single seal stack to understand the leakage behavior as well as the range of safe operating conditions under delayed gas leakage. The operating conditions for the experiments have been adopted to simulate drilling rigs. Hence, temperatures ranging from room temperature to 394.15 K and 477.15 K, diverse pressures from 4.14 MPa to 68.95 MPa, and variable motion speeds (0 RPM, 2 RPM, and 10 RPM) were incorporated in the experiments. The study revealed a positive correlation between leakage rate with both pressure and dynamic motion, reflecting valve opening and closing actions. In contrast, a negative correlation was noted between leakage rate and temperature in both static and dynamic conditions. At 68.95 MPa, the highest observed leak rate was 2.96 x 10-4 mol/s at room temperature, nearly ninety-five times higher than the rate recorded at 4.14 MPa (3.08 x 10-6 mol/s). Also, at an elevated temperature of 477.15 K, the leak rate significantly decreased to 1.08 x 10-5 mol/s, approximately twenty-six times lower than the room temperature rate. Furthermore, the study revealed that the influence of motion on leak rate diminished significantly at high temperatures compared to low temperatures, indicating a complex interplay between motion, temperature, and leakage behavior in the tested seals. Additionally, this investigation encompasses a thorough imaging analysis of the seals, aimed at assessing structural changes and the overall seal condition under varying operational circumstances. This research promises to guide customized sealing material development, enhancing safety and environmental performance in the oil and gas sector, making a valuable contribution to the industry.