Change search
ReferencesLink to record
Permanent link

Direct link
Simulations of Dual Gradient Drilling: Analytical and Theoretical Studies of tripping- and pressure trapping operations when using Dual Gradient Drilling in deep waters
Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, Department of Petroleum Engineering and Applied Geophysics.
2012 (English)MasteroppgaveStudent thesis
Abstract [en]

To cover the world’s future consume of hydrocarbons, technological improvements are needed, turning currently unreachable and unprofitable reservoirs into the opposite. The main focus of this thesis, Dual Gradient Drilling (DGD), is a drilling technology that is ideal for drilling in ultra-deep waters, and could prove vital in drilling the reservoirs that are currently undrillable. This will increase the possible supply of hydrocarbons available for consumption. DGD is not fully accepted in the drilling industry, and DGD is still considered unconventional. In this thesis, simulations investigating pressure control in a DGD system are done, showing possibilities and limitations when using DGD. Also, it is done a study of how the challenges faced on the Macondo prospect in the Gulf of Mexico could have been solved better by using DGD instead of the conventional drilling methods. MATLAB was used for mathematical simulation of the control of the hydraulic pumping system. The program reads field- and equipment specific input data from an excel sheet. The different input parameters are changed separately, and simulations are run for each parameter change, showing each parameter’s effect caused to the system abilities. Criteria for approved well control are set, and by trial and error with the program, requirements for pump rates, well bore design and pressure safety margins needed are found, presented and discussed. It is here shown that the currently available pumping rates are not able to control the pressure as agile as other available drilling technology can, using the marine riser size currently developed. A subsea pump producing rates of more than 13000LPM, the double of what can be produced today, is needed. Utilizing a narrower marine drilling riser, with an inner diameter (ID) of 12¼” instead of the conventional riser with 19½” ID, can increase the speed of a pressure change with 171%; from 0.045bar/s to 0.121bar/s, when other parameters are kept constant. Because of linearity, a doubling of pumprates will result in a doubling of pressure change speed. It is here concluded that sufficiently agile wellbore control, depends on the development of a narrower riser and higher subsea pump rates. Other unconventional drilling currently available, like Managed Pressure Drilling (MPD), is far superior to DGD when it comes to quickness and accuracy in keeping the BHP at a desired level.

Place, publisher, year, edition, pages
Institutt for petroleumsteknologi og anvendt geofysikk , 2012. , 106 p.
Keyword [no]
ntnudaim:8099, MTGEOP Geofag og petroleumsteknologi, Boreteknologi
URN: urn:nbn:no:ntnu:diva-19360Local ID: ntnudaim:8099OAI: diva2:566978
Available from: 2012-11-11 Created: 2012-11-10 Last updated: 2013-06-07Bibliographically approved

Open Access in DiVA

fulltext(2117 kB)2897 downloads
File information
File name FULLTEXT01.pdfFile size 2117 kBChecksum SHA-512
Type fulltextMimetype application/pdf
cover(184 kB)39 downloads
File information
File name COVER01.pdfFile size 184 kBChecksum SHA-512
Type coverMimetype application/pdf
attachment(51 kB)45 downloads
File information
File name ATTACHMENT01.zipFile size 51 kBChecksum SHA-512
Type attachmentMimetype application/zip

By organisation
Department of Petroleum Engineering and Applied Geophysics

Search outside of DiVA

GoogleGoogle Scholar
Total: 2897 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 263 hits
ReferencesLink to record
Permanent link

Direct link