Abstract: Daniudi Gas Field is a low porous, low permeable, low pressure and multizones gas field, single zone fracturing stimulation cannot meet the need of effective production so that a new method has to be used, i.e. fracturing two zones with double packers and putting the both zones into production without moving the string after stimulation. In consideration of the problems existing in separating zones fracturing string with hydraulic packer combination, a string system fitting to Daniudi Gas Field is developed which makes use of mechanical packers combination and puts the fractured zones into production after stimulation, thus the reliability of the fracturing string is enhanced. The prominent point about the combination is the use of double sliding sleeve sand injection valve, which makes the communication between upper zone and lower zone after fracturing treatment, therefore two zones can be produced together without tripping out of the string. From 2005 to 2006, 114 layers of 57 wells in Daniudi Gas Field were treated by using this string combination with a success rate of 97%, remarkable economical effect is achieved.

Key words: Daniudi Gas Field, separating layer fracturing, low permeability, fracturing string, packers