Well drilling in weak clay-claystone rocks: challenges and remedies

Abstract

The maintenance safety of the wellbore in clay-claystone formations is important aim for modern investigations for companies in Western Siberia as usual. There is a lot of non-productive time to do sidetrack due to weak clay rocks. The analysis was done to solve these true challenges of the sidetrack into the different production zones. There is a lot of non-productive time for the accident responses because of wellbore lose control. For example, 50 % of drilling time has non-productive time to stabilize wellbore. There are the most effective ways to prevent losing control of wellbore: control of mud density and pressure drop variation, using of inhibitors with high effectivity, applying stabilizing bath in dangerous zones.