• Shallow water flow may occur during or after cement job • Under water blow out has happened • Gas flow may occur after a cement job in deepwater environments that contain major hydrate zones. • Destabilization of hydrates after the cement job is confirmed by downhole cameras. • The gas flow could slow down in hours to days if the de- stabilization is not severe. • However, the consequences could be more severe in worse cases.
Page 13 lists the design objectives but then concedes they can’t all be met at once:
Deepwater Well Objectives
• Cement slurry should be placed in the entire annulus with no losses • Temperature increase during slurry hydration should not destabilize hydrates • There should be no influx of shallow water or gas into the annulus • The cement slurry should develop strength in the shortest time after placement Conditions in deepwater wells are not conducive to achieving all of these objectives simultaneously