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... 

Casing failure is one of the mainly problems of hydrocarbon fields that may cause wells out of service and impose heavy costs on oil companies. There exist many theories that may cause casing failure including: the plastic behavior of surrounding formations, the effects of reservoir depletion, over-pressured formations, weak cementing operations, fault activation, and local stresses applied on casing. In salt-rich formations, creep behavior can be the main cause of casing failure, too.The purpose of this study is to evaluate the causes affecting casing failure via experimental studies and numerical simulation with the focus on the conditions governing south-west Iranian oil fields, where the...