The of these systems, as spelled out in API RP 53, are to confine well fluids to the wellbore, provide a means to add fluid to the wellbore, and allow controlled volumes to be withdrawn from the wellbore. Diverter systems are also addressed, although their primary purpose is to safely divert flow rather than to confine fluids within the wellbore. For more detailed diverter guidance, the document refers users to API Recommended Practice 64.
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