Experimental Analysis and Mechanistic Modeling of Wellbore Strengthening

Mostafavi Toroqi, Seyyed Vahidreza

Experimental Analysis and Mechanistic Modeling of Wellbore Strengthening

atmire.migration.oldid	432
dc.contributor.advisor	Hareland, Geir
dc.contributor.advisor	Aadnoy, Bernt
dc.contributor.advisor	Husein, Maen
dc.contributor.author	Mostafavi Toroqi, Seyyed Vahidreza
dc.date.accessioned	2012-10-04T14:50:21Z
dc.date.available	2012-11-13T08:01:31Z
dc.date.issued	2012-10-04
dc.date.submitted	2012	en
dc.description.abstract	Wellbore strengthening refers to the science and technology of increasing the pressure level at which circulation loss to the formation occurs. Although a fairly wide range of technologies have been proposed and tested, the application of engineered drilling fluids has proven to be the most promising approach. Circulation loss, which is one of the most troublesome issues occurring in drilling operations, is experienced at varying levels of severity. It is most expected in highly permeable formations, fractures and caverns. Lost circulation may have several consequences including fluid inflow, wellbore collapse, formation damage, non-productive rig time and environmental contamination. In order to mitigate the risks of circulation loss, a broad range of treatments and preventive methods have been practiced such as application of Lost Circulation Materials (LCM), cement plugs, squeeze gunk, gels and technologies like aerated drilling and stress caging. It has been observed that lost circulation occurs at varying pressure levels dependent on drilling fluid properties. This observation builds the foundation for drilling fluid based wellbore strengthening. Wellbore strengthening has been described previously but a general model to take into account the effects of fluid properties and its constituents does not exist. In addition, the governing mechanisms of this process are not well understood and explained in the literature. In this study a comprehensive literature survey and an extensive experimental analysis was completed to determine the mechanism of and contributing factors to wellbore strengthening. Next, a mechanistic model was developed and verified to predict the formation resistance prior to allowing drilling fluid loss. A field case of wellbore strengthening was also studied where the developed model exhibited a very good agreement. Results from this research are mostly directed towards circulation loss prevention via tensile fractures. However, they might be applicable for pore scale seepage loss through gravels and natural fractures. In the first chapter, an introduction to the circulation loss issue and its consequences is presented. Chapter two is dedicated to a brief review on wellbore stability analysis and a thorough survey on wellbore strengthening. In chapter three, the experimental part of this research is explained and its results are discussed. In chapter four, the experimental results are applied to build a mechanistic model. The model is analyzed and verified using a field case of wellbore strengthening. Conclusions of this research and some recommendation for future studies are presented in Chapter five.	en_US
dc.identifier.citation	Mostafavi Toroqi, S. V. (2012). Experimental Analysis and Mechanistic Modeling of Wellbore Strengthening (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26049	en_US
dc.identifier.doi	http://dx.doi.org/10.11575/PRISM/26049
dc.identifier.uri	http://hdl.handle.net/11023/300
dc.language.iso	eng
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary	en
dc.publisher.place	Calgary	en
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Engineering--Petroleum
dc.subject.classification	Wellbore Strengthening	en_US
dc.subject.classification	Circulation Loss	en_US
dc.subject.classification	Drilling Fluid	en_US
dc.subject.classification	Resilience Modulus	en_US
dc.subject.classification	Strengthening model	en_US
dc.title	Experimental Analysis and Mechanistic Modeling of Wellbore Strengthening
dc.type	doctoral thesis
thesis.degree.discipline	Chemical and Petroleum Engineering
thesis.degree.grantor	University of Calgary
thesis.degree.name	Doctor of Philosophy (PhD)
ucalgary.item.requestcopy	true