The SuperFill surge-reduction system allows wellbore fluids to enter the casing freely and exit the drillpipe, effectively reducing surge pressures and helping prevent expensive drilling-fluid losses.

SuperFill AFE assembly consists of an outer case or collar with holes through which wellbore fluids can freely pass, thus reducing surge pressures. An internal sliding sleeve made from steel or other drillable material is held in position to ensure that the ports in the collar remain open. After the casing string has been run into the hole, the sliding sleeve can be shifted into the locked position to cover the ports in the outer collar.

Under normal circumstances, conventional floating and guiding equipment fitted with special valves allows wellbore fluids to enter the casing; however, on liners of subsea completions,

The SuperFill system diverts well fluids to a point above the liner, helping avoid formation damage from surging wellbore fluid. (Graphic courtesy Halliburton)
the casing is run into the hole on the end of drillpipe. Although the wellbore fluid freely enters the casing through the AFE collar, the restricted inside diameter of the drillpipe still increases surge pressures. In these situations, SuperFill diverter can be installed below the drillpipe and just above the top of the liner. Wellbore fluids enter the casing through the collar and exit through the SuperFill diverter.

The SuperFill Collar/Shoe installed on the lower end of the liner or casing allows the wellbore fluid to enter the liner or casing and exit the drillpipe directly above the liner. This arrangement reduces the pressure drop and the surge pressure on the formation when the liner or casing is being run, reducing mud loss into the formation.

The surge-reduction system helps to:
• Reduce lost circulation problems;
• Prevent fluid damage to producing formations;
• Assure achievement of a good primary cement job;
• Reduce the need for remedial cement jobs;
• Minimize loss of expensive drilling fluids; and
• Reduce risk of differential-pressure sticking of pipe.

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