Performance Analysis of Rotary Dynamic Seals for Suction Modules in Riserless Drilling Systems

Summary The suction module, serving as a critical component in riserless drilling systems, determines the feasibility of achieving zero drilling fluid leakage through its sealing performance. Due to the relative circumferential motion between the drillpipe and the suction module, a rotating dynamic sealing solution is essential to ensure the module’s sealing integrity. Given the high-pressure and highly abrasive operating conditions characteristic of the suction module’s dynamic seal, the Kalsi seal ring was selected for this application. A finite element analysis model was established to evaluate the Kalsi seal’s sealing performance, yielding its von Mises stress distribution and static lip contact stress. Concurrently, a 3D mathematical model for its lubrication performance was developed based on the Reynolds equation and Boussinesq equation, solving for key parameters including oil film pressure, oil film thickness, and leakage rate. Sensitivity analysis of the seal’s sealing and lubrication performance revealed that sealing pressure differential and compression rates exert significant influences. Increasing the sealing pressure differential enhances sealing performance and lubricant-side lubrication but degrades environmental-side lubrication and increases leakage. Conversely, increasing the compression rates improves sealing performance and reduces leakage but detrimentally impacts overall lubrication performance. Utilizing average oil film thickness, minimum oil film thickness, maximum contact stress, maximum von Mises stress, and leakage rate as evaluation criteria, the response surface method (RSM) identified the optimal parameter combination as a sealing pressure differential of 6 MPa and a compression rate of 10%.