Abstract
The conventional wellhead (WH) system with slip-on weld and slip-type hangers has been in the industry for several decades as it is simple and straightforward. However, the system entails and imposes certain risks and excessive time that cause unnecessary additional costs. This paper will discuss the differences between the conventional wellhead system and the Fluted Mandrel Hanger (FMH) system and the optimization opportunities that FMH system promotes.
The FMH system uses a mandrel that sets once it lands on the load shoulder on the internal profile of the wellhead and has flutes that facilitates returns to the surface. To prevent damaging the internal profile, before drilling, a wear bushing must be installed due to the delicacy of the system. After drilling the hole section to casing point, a rat hole of 5 - 10 ft is maintained to ensure safe and smooth landing of the FMH. After landing, the cementing operation can be commenced and then the Pack-off can be set and tested. The FMH system has proven its efficiency and cost-effectiveness in comparison to the conventional system. To elaborate, in a dual stage cementing job, the WOC time on the first stage to lift the Well Control Equipment (WCE) is eliminated which saves rig time, leading to considerable cost savings especially in offshore rigs. Moreover, the system provides and promotes safer operations by eliminating cutting or dressing since the casing stub of the FMH is a standardized design that fits through the next casing or tubing spool. In addition, it eliminates an extra step of lifting the diverter or Blowout Preventer (BOP) to set the slip-type hanger on the casing.
