Drilling and Completion Challenges in Gas Wells of Iranian Southern Gas Condensate Reservoirs

According to Iran Petroleum Ministry, Iran's proved natural gas reserves are about 1,045.7×10^12 cu ft (29,610 km3) or about 15.8% of world's total reserves, of which 33% are as associated gas and 67% is in non associated gas fields. It has the world's second largest reserves after Russia. This paper reviews drilling challenges in retro grade gas condensate wells in South Zagros area. Important problems in drilling and well completion in this area are: High mud loss, Shale layers existence between reservoir layers or reservoir layers with high shale percentages that can cause problems while drilling operation and also production. Blue-zone layer, inappropriate cementing , sloughing , unstable well wall ,gaining drilling fluid flow and drilling fluid increase , drilling in hard layers , designing liner and casing shoe in production interval and etc… which makes serious challenges in drilling and completion of gas wells in south of Iran.