Sharif Digital Repository

The wellbore instability is one of the challenging problems in the oil industry, which entails huge costs for the industry every year. This phenomenon not only causes numerous problems in drilling and completion of wells, but also reduces production and loss of wells. In recent years, this problem has become much more serious in the Kupal oilfield. As a result, a large number of wells drilled in the field shortly after completion face with the problem of instability, integrity and casing collapse. According to the studies, one of the main causes of such a problem is the Gachsaran high pressure formation. Despite the complexity and importance of this issue, there is not a comprehensive study...