METHOD FOR DETERMINATION OF THE BALANCE MUD CAP PLACEMENT TECHNIQUE IN MANAGED PRESSURE DRILLING

Managed pressure drilling is a drilling technique used to efficiently reduce the drilling risk of the formation with narrow safe drilling fluid density and non-productive time.The technique is using the back-pressure compensation system,automated choke manifold and dedicated software to realize continuously control the bottomhole pressure.In order to realize continuous pressure control during trips,the usual method was firstly to trip out to a certain depth,and then to place the balance mud cap.The length of the tripping out with pressure could be easily affected by the proper performance and volume of the balance mud cap which was useful to maintain the constant pressure in the whole process,reduce the labour intensity and improve the drilling efficiency.