TY - THES

T1 - Investigation of the Effect of Modern Drilling Technology on Wellbore Stability in the Tertiary and Jurassic in North-Western Germany

AU - Mikula, Melanie

N1 - no embargo

PY - 2007

Y1 - 2007

N2 - Borehole stability is a main contributor to the successful drilling of a well within a planned time and budget frame. The task of this work is to investigate the influence of modern drilling technologies on wellbore stability in Tertiary and Jurassic formations in North-Western Germany. Initially, changes in applied drilling technologies are identified which were implemented in the past two decades: the replacement of kelly and rotary table by topdrive systems, directional drilling in the tophole section, shale inhibition by oil-based mud substitutes instead of KCl-containing water-based muds, reduced roundtrips due to high-performance bits as well as improved borehole hydraulics. Those serve as basis for the comparison of old and recent wells. The findings of this comparison are then evaluated regarding their influence on wellbore stability. In the next step, parameters termed positive are excluded, leaving only those with a negative effect on borehole instability. This way the reasons for problems with wellbore stability in a specific well can be identified. Finally project-specific recommendations on how to avoid future stability problems are given.

AB - Borehole stability is a main contributor to the successful drilling of a well within a planned time and budget frame. The task of this work is to investigate the influence of modern drilling technologies on wellbore stability in Tertiary and Jurassic formations in North-Western Germany. Initially, changes in applied drilling technologies are identified which were implemented in the past two decades: the replacement of kelly and rotary table by topdrive systems, directional drilling in the tophole section, shale inhibition by oil-based mud substitutes instead of KCl-containing water-based muds, reduced roundtrips due to high-performance bits as well as improved borehole hydraulics. Those serve as basis for the comparison of old and recent wells. The findings of this comparison are then evaluated regarding their influence on wellbore stability. In the next step, parameters termed positive are excluded, leaving only those with a negative effect on borehole instability. This way the reasons for problems with wellbore stability in a specific well can be identified. Finally project-specific recommendations on how to avoid future stability problems are given.

KW - Wellbore stability Drilling technology Tertiary Jurassic North-Western Germany

KW - Bohrlochstabilität Bohrtechnologie Tertiär Jura Nordwestdeutschland

M3 - Master's Thesis

ER -