An Innovative Technique to Sustain Well Performance

In the case study field, most of the wells are being completed with dual strings where there is no accessibility in the upper zone (short string). This leads to no well intervention in the future if there is any gas or water breakthrough or in some cases the formation collapse. However, formation collapse was recently observed in the certain dense (impermeable) layers which are liable to hole collapse when in contact with HCl acid during stimulation operation hence resulting in hole plugging. This leads to losing the production / injection from the upper zone and requires rig workover to clean out and recomplete the well. This phenonmenon was further confirmed by several experiments performed on different core samples in the Lab. A quick and cost effective solution was looked into and found that 4-1/2" liner, called "drop-off", can be run and set in the upper drain of the well to avoid any future breakthroughs or hole collapse. 4-1/2" drop-off liner was successfully run in multiple wells and proved to be very efficient. This cost effective innovative technique resulted in restoring the wellbore stability and help in sustaining the production from the upper drain.