MSc Thesis: Well Bore Stability - Principles and Analysis in Geothermal Well Drilling

Samuel Ikinya Nganga successfully defends his master's thesis


REYKJAVIK, May 16 - Recently, Samuel Ikinya Nganga, MSc in Sustainable Energy Engineering successfully defended his master's thesis project, in which he analysed the well bore stability, with respect of principles and analysis in geothermal well drilling. Samuel was supervised by Juliet Newson from Reykjavik University and Björn Már Sveinbjörnsson from Iceland GeoSurvey (ÍSOR), Iceland's consulting and research institute providing services to the nation's power industry, government and other companies. 

Samuel's research focused on analysing the well bore stability, specifically on how to deal with mechanical failure and stresses at the well bore walls in Olkaria geothermal field, Kenya. Additionally, he also studied the drilling fluid circulation, conducted stress analysis of vertical and directional wells and compared the available drilling data and practices in Iceland. The Olkaria geothermal field is crossed by the East African Rift System (EARS) and hence, has a high geothermal capacity. The field has been previously drilled with 300 wells and currently has a power generation of over 650 MW. 

Samuel defined well bore stability as the disturbance of formation balance through materials removal during drilling action. In his research, Samuel focused on studying five wells in Olkaria, and one vertical and four directional wells in Reykjanes geothermal field, Iceland. He chose these wells particularly because they all experience well bore instability during development, such as loss of drilling fluid circulation, collapsed formations and loss of cement. Samuel evaluated the well bore stress in both vertical and directional wells through a series of equations and using the failure theory. He plotted the Mohr's circle diagrams using maximum effective stresses at different depths and drilling fluid densities of 500, 800, 1000, 1200 and 1800 kg/m3.

The results of his analysis indicate that well bore stability increases with increasing drilling weight. This is due to the fact that compressive hoop stresses that induce well bore collapse are reduced. The impact of instabilities can be detrimental to geothermal drilling operations as it adds to the overall drilling costs, increases days, increases material consumption, as well as affects the well output. As such, Samuel's research will add to well bore stability knowledge and contribute towards planning future geothermal drilling projects. To read more about Samuel's work, click on the following link .

Congratulations, Samuel for an excellent thesis!


About Iceland School of Energy

By bringing together the best from industry and academia, Iceland School of Energy provides a unique, and comprehensive training for its students. A wide range of courses taught by the very best in their field open a broad spectrum of possibilities for students and allow for individual study designs. Focus is put on close collaboration with industry experts while maintaining high academic quality of the work.

Full-time graduate studies

Short programmes and professional development