ECD Management Toolbox for Floating Drilling Units
- John-Morten Godhavn (AGR Enhanced Drilling) | Espen Hauge (AGR Enhanced Drilling) | Dag Ove Molde (AGR Enhanced Drilling) | Ivar Kjøsnes (AGR Enhanced Drilling) | Sturle Gaassand (AGR Enhanced Drilling) | Statoil Børre Fossli (AGR Enhanced Drilling) | Roger Stave (AGR Enhanced Drilling)
- Document ID
- Offshore Technology Conference
- Offshore Technology Conference, 05-08 May, Houston, Texas
- Publication Date
- Document Type
- Conference Paper
- 2014. Offshore Technology Conference
- 4.2.4 Risers, 4.1.2 Separation and Treating, 1.7.6 Wellbore Pressure Management, 4.2 Pipelines, Flowlines and Risers, 1.10 Drilling Equipment, 1.7.2 Managed Pressure Drilling, 1.10 Drilling Equipment, 4 Facilities Design, Construction and Operation, 4.1 Processing Systems and Design, 1.6 Drilling Operations
- Managed Pressure Drilling, Dual Gradient Drilling, ECD Management, Controlled Mud Level
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This paper presents ongoing work as well as plans and ideas for future development of a toolbox of managed pressure drilling systems that solves major challenges when drilling in both mid- and deep waters. The toolbox contains three applications based on field proven Controlled Mud Level (CML) technology. Additional benefits can be achieved by combining controlled mud level technology with other technology elements such as a fast closing annular or a sealing element in the riser, usually referred to as a rotating control device (RCD).
The first application is called CML. A subsea pump module (SPM) is used to pump the mud returns to surface in a separate mud return line (MRL). The SPM is used to regulate and manage the bottomhole pressure by adjusting the mud level in the riser. High bottomhole pressure or Equivalent Circulating Density (ECD) due to friction and other effects can be avoided by reducing the mud level in the riser accordingly. One of the objectives with this technology is to avoid or reduce losses both during drilling and other operations such as cementing.
In the second application called ECD-Management, CML is combined with a fast closing annular installed in the riser just above the SPM. This enables extending the operating envelope of the technology to a point where loss of circulating capability could potentially cause an underbalance scenario in the well. The hydrostatic pressure from the drill string or MRL can be trapped within a few seconds by closing the fast closing annular element, e.g. on unplanned rig pump stops or formation pack off situations. A second annular will also be installed to be used during connections in order to save time filling up the riser to compensate for the ECD effect (friction losses in the annulus).
The third application in the toolbox is called ECD-Control. Here a subsea RCD or a sealing element is installed in the riser and the SPM can then be used to manipulate the pressure below the RCD to compensate for ECD variations. The riser is always topped up with mud and hydrostatic overbalance is maintained.
The paper will present simulation results comparing the different technologies and address benefits and challenges with the different methods.
|File Size||5 MB||Number of Pages||23|
Godhavn, J.-M., Control Requirements for High-End Automatic MPD Operations, SPE 119442, SPE/IADC Drilling Conference and Exhibition, Amsterdam, 2009. Journal version: Control Requirements for Automatic Managed Pressure Drilling System, SPE Drilling & Completion Journal, Volume 25, Number 3, pp. 336-345, September 2010.