Abstract
This paper analyzed the characteristics of managed pressure drilling (MPD) technology and impact of wellhead back pressure on the wellbore annulus pressure profile, and found that the application of this technology provides situation for improvement in the current casing program design. Meanwhile, the equivalent density of drilling fluid in wellbore annulus needs to consider the impact of back pressure. On this basis, casing program design for top-down design approach and multi-pressure system formation in MPD are established. Comparing and analyzing the results of casing program design in MPD and conventional drilling, it can be concluded that for the top-down design method, each layer of casing can reach to a deeper depth. It can also reduce the casing level for the multi-pressure system formation using wellhead back pressure to make the wellbore annulus pressure profiles bend. Thus, it can cleverly pass through the complex formation which needs multi-layer intermediate casings in conventional drilling. In this condition, the well structure can be simplified