in operation the gas lift system of this invention the system can be operated as a typical gas lift system as shown in fig2 or fig6 at the early stage of the well life should the well still has high reservoir pressures or has low percentage of water cut in the well fluids also it can be converted for operating as fig3 or fig7 to utilize the bypass gas lift system for injecting lifting gas to the wellbore at the bottom hole later on once the reservoir pressures in the perforation intervals 15 16 deplete or the percentage of water cut increases if operating like the embodiment as shown in fig3 it just requires changing the dummy valve installing inside the u201c tk bypass mandrel u201d 17 with the orifice valve by wireline intervention with respect to fig3 the lifting gas is injected to the first part tubing string 6 a above the dual port packer 12 as gas bubbles and it is delivered passing thru the said packer 12 by the operation of the u201c tk bypass mandrel u201d 17 cooperating with the tube 18 used as a conduit for delivering lifting gas to the u201c jp bypass nipple sub u201d 22 the u201c jp bypass nipple sub u201d 22 receives lifting gas from the tube 18 and delivers such lifting gas down to the bottom hole for injecting to the wellbore proximate at perforation intervals 15 and perforation intervals 16 otherwise if operating like another embodiment shown in fig7 the lifting gas.