Wellbore Instability Mechanism and Its Application in Wei12-1 N B Oilfield

The wellbore stability is affected by mechanics factors and physical chemistry factors,which is resulted from rock mechanics and mud chemical.There are many researches on chemical anti-caving mechanism,but little on mechanic mechanism,mechanic and chemical mechanism.It cannot satisfy engineering for short of a systemic wellbore stability theory and control technology.The article explores the mechanic mechanism of wellbore stability,and introduces the findings used in Wei12-1 N B oilfield.