Abstract This paper describes the challenges addressed during testing, completion and subsequent re-entry for Jurassic prospects in an ultra-deep HPHT exploratory well in highly sour environments. The approach and methodology adopted to address the problems related to perforation, Coiled Tubing, stimulation and well testing operations are also discussed in this paper. The exploration activities for gas in North Kuwait are in progress at high pace. An exploratory well, second deepest in the State of Kuwait, drilled in Mutriba field to a depth of 22, 094 feet to cover Triassic and Paleozoic sections. All these deeper formations have very low porosity and permeability. Two formations, Kra-Almaru and Khuff were perforated and tested, which showed the presence of feeble gas. Based on the study, later it was decided to test and complete this well in Jurassic formation through re-entry. The re-entry in this ultra-deep well was full of challenges due to HPHT conditions, high surface pressure and well killing issues. The re-entry was planned under the supervision of highly skilled task team. A snubbing unit was utilized to isolate the open perforations of the Triassic zone with cement. Subsequently a workover rig was deployed to test the prospect of Jurassic reservoir. Several severe mechanical problems like fishing, isolation and retrieving the tubing were encountered prior to well testing, which were efficiently addressed. Testing the Jurassic reservoir behind two heavy walled casings(7" 46.4 ppf and 8-5/8" 40 ppf), combined with extreme sour and HPHT environment warranted high HSE and technical precautions. Special software was run to simulate the depth of penetration in two walled casings. The targeted Jurassic interval was perforated with suitable TCP guns at a depth of around 16, 260 feet. During testing, the formation fluid showed presence of unexpectedly high concentration of 20% H2S and 2% CO2.In this extreme sour environment, Coiled tubing operations, stimulation, flowing the well, and fluid disposal were of utmost challenge. By overcoming all the challenges, this well was successfully perforated, stimulated and tested, which led to the first commercial discovery of Oil & Gas within the Jurassic Reservoir in Mutriba field.