Mohsen Ghorbankhani - Young Research Club, Omidieh Branch
Mehdi Ali Mohammadi - Islamic Azad University, Omidieh Branch
Mahdi Bakhtbidar - Young Research Club, Omidieh Branch
Amin Safaei - Islamic Azad University Omidieh Branch

Coiled Tubing Drilling (CTD) as performed today is generally considered to have begun in 1991 with a horizontal sidetrack re-entry drilled by Oryx Energy in the Austin Chalk of Texas. From that time to the present, the technology advanced rapidly, with on the order of 4000 CTD operations completed (Figure 1). Currently, about 900-1000 CTD wells are completed a year, including about 120 directional re-entries and 800 new shallow vertical wells (many of these vertical wells are in Canada). Several key factors have contributed to the rapid rise in activity[1]: - The CT service industry has achieved a level of maturity capable of providing necessary equipment and basic techniques with the required degree of reliability.- Technical advantages exist for CTD that enable it to compete in and sometimes dominate certain niche markets.

Coiled Tubing Drilling,Directional drilling