Mohammad Hussein Dalvand - Petroleum Department, Islamic Azad University, Omidieh Branch, Omidieh, Khuzestan, Iran
Davoud Malekshahi - Petroleum Department, Islamic Azad University, Omidieh Branch, Omidieh, Khuzestan, Iran
Amir Mohammadi - Petroleum Department, Islamic Azad University, Omidieh Branch, Omidieh, Khuzestan, Iran
Shahram Alghasi - Young Researchers Club, Omidieh Branch, Islamic Azad University, Omidieh, Khuzestan, Iran

Shale gas is an unconventional type of natural gas; having the same composition as a conventional one, but produced from low permeability sediments and rich in organic matter. In shale gas natural fractures canusually do not provide adequate pathways for sufficient flow of hydrocarbons into a well and because of their low permeability, they are rarely economic. Now production of shale gas is currently possible where shale is fractured. Natural gas from shale is developed using horizontal drilling and multi-stage hydraulic fracturing. Horizontal drilling is used to provide greater access to the gas trapped in the producing formation. Hydraulicfracturing pumps fluid (water with a small amount of additives) and sand or other proppants down along thewell at high pressure. The pressure causes the surrounding brittle rock to fracture. Hydraulic fracturing cansignificantly increase the yield of a well. When it is combined with horizontal drilling, unprofitable and uneconomical rock formations are often converted into productive natural gas fields. In this paper we initially describe shale gas, properties needed for economical shale gas production, shale gas reservoirs evaluation and its production methods. Finally we lead and end shale gas topics to Iran and describe shale gas in Iran

Unconventional Resource, Shale Gas, Tight Gas, Hydraulic Fracture, Horizontal Drilling