Failure of protection against particle invasion in hard/soft dynamic seal: Modeling and observation

Particles invasion into sealing interface is difficult to avoid in downhole conditions, which directly induces the failure of FKM O-ring dynamic seals. To enhance the performance of hard/soft dynamic seals in particles environment, the work on particles invasion has been initiated. A displacement model for particles invasion was developed and tested. In-situ observations were used to investigate particles invasion process under different particles sizes and assembly compression forces. Theory and tests showed matching results that particles sizes and compression forces had significant effects on particles invasion. In addition, a particles sizes control strategy based on the model was tested. This work has clarified the invasion behavior of particles and provided recommendations for the elastomer dynamic seals assembly in particles environment.