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Unformatted text preview: convert the float collar, a ball (in this case an “Allamon ball” because the float collar was manufactured by Allamon) rests in the auto‐fill tube when running the casing into the well and when mud pumping starts it restricts the flow of mud by diverting the mud through two small ports in the auto‐fill tube. Circulation through these ports creates a differential pressure in the float collar, forcing the auto‐fill tube out of the float collar and allowing the check valves to close. In doing so, a float collar, which is set near the bottom of the casing string, acts as a check valve and prevents cement that is pumped down through the casing from flowing back into the shoe track (which is the distance between the float collar and end of the casing) once the cement is in place. If the float collar fails to convert, it is possible for “reverse flow” or “u‐tubing” flow to occur from the bottom of the casing up the wellbore toward the rig. BP‐HZN‐CEC022433. 115 49 Auto-Fill Ball Float Check Valve
Auto-Fill Tube Circulation Port Fig...
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