Change search
ReferencesLink to record
Permanent link

Direct link
Simulating Underbalanced Drilling: Development of a GUI flow simulator to evaluate UBD operations for aerated fluids and foams
Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, Department of Petroleum Engineering and Applied Geophysics.
2014 (English)MasteroppgaveStudent thesis
Abstract [en]

As more oil fields mature, new methods are required to be able to drill additional wells without damaging the reservoir and to limit pressure related drilling problems. This can in most cases be solved by drilling underbalanced, intentionally lowering the pressure below the reservoir pressure, allowing the well to flow. Systems available to drill underbalanced include; air, gas, mist, stable foam, foam with back-pressure, aerated mud and oils. The thesis focuses mainly on foam drilling and drilling with aerated systems. Both systems are pneumatic drilling fluids, this means they are a mixture of a liquid- and a gas phase. The main difference between foam and aerated systems is how the fluid structure is built up. When drilling with aerated fluids, no emulsifier or stabilization agent is added to the fluid, so the gas phase will normally travel faster than the liquid phase due to gravitational forces. Foams are added foaming agents so that the fluid system remains stable by trapping the gas bubbles inside a liquid film, making the fluid act as normal onephase flow. The thesis explains the theory behind, usage, design and operational procedures for these fluid systems. In this master thesis an advanced fluid simulator was developed in MATLAB to simulate drilling with these fluids, and to design operational limits in the planning phase. The finished program is presented in a graphical interface which easily allows the user to run even complex simulations regarding; well path, reservoir model, tubular- and fluid design. For the two-phase flow modeling eight different empirical pressure correlations were implemented in the simulator. The first two-phase flow model described in the literature on flow modeling, was developed by Poettmann & Carpenter, and is one of the simplest models available. This model was included in two versions. Besides this model, two other models are included from each of the three main categories; neither slippage nor flow regimes considered, only slippage considered, and; both slippage and flow regimes considered. The models that consider both slippage and flow regimes, such as Beggs & Brill, are complex models which require much computational force. However these models will often produce very reliable results. For foam modeling, six different empirical viscosity models were implemented. Einstein was the first to describe foam rheology mathematically, and his model is the simplest model included in the simulator. Some of the simpler models included in the simulator produces output with much uncertainty, however more complex models such as Sanghani produce more trustworthy results. Multiple simulations were run for foam and aerated system utilizing these models with a large range of varying inputs. The results from simulations proved to provide reliable outputs, with deviations well within the expected range.

Place, publisher, year, edition, pages
Institutt for petroleumsteknologi og anvendt geofysikk , 2014. , 167 p.
URN: urn:nbn:no:ntnu:diva-25585Local ID: ntnudaim:10850OAI: diva2:736818
Available from: 2014-08-08 Created: 2014-08-08 Last updated: 2014-08-08Bibliographically approved

Open Access in DiVA

fulltext(4427 kB)1206 downloads
File information
File name FULLTEXT01.pdfFile size 4427 kBChecksum SHA-512
Type fulltextMimetype application/pdf
cover(184 kB)1 downloads
File information
File name COVER01.pdfFile size 184 kBChecksum SHA-512
Type coverMimetype application/pdf
attachment(2349 kB)21 downloads
File information
File name ATTACHMENT01.zipFile size 2349 kBChecksum SHA-512
Type attachmentMimetype application/zip

By organisation
Department of Petroleum Engineering and Applied Geophysics

Search outside of DiVA

GoogleGoogle Scholar
Total: 1206 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: 110 hits
ReferencesLink to record
Permanent link

Direct link