Causes of destruction and instability of deep water wells of Kohgilouyeh

Today, the most applied way to access underground in Iran and the world is digging water wells. In addition to exploit advantages, pumping wells have always have several problems such as degradation and instability of their structure, reducing the discharge, forming masses of sand clogging and loss of equipment. According to current statistics, 60% of deep wells drilled in the Kohgiluyeh have a shelf life less than 4 years. The high costs of drilling deep wells and geological sensitivity and degradation and successive failure of wells, deep wells need to study about effective life and affective Factors on wells destruction and preventive methods and appropriate utilization of wells would be inevitable. A sample of 18 wells in the area was used for chemical analysis and preparing and grading tests. Laboratory and field studies and available information, the main causes of destruction and instability of wells in the studied zone were detected as poor design of wells, thin layers of granulated in saturated layer, use of screens with inappropriate size and pores and excessive removal and fouling.