Lost circulation and wellbore instabilities are major problems in today’s drilling industry like stated in several scientific papers and books. But also the occurrence of sour gases need special attention especially in the planning process. To fight those high technology is required and wells get more complex every time. Several times in spite of improved seismic and geological information the actual formation sequence and characterisation are different than the planned data. After gathering the theory for above mentioned problems, two different wells were analysed from the Akri-Bijeel block in Northern Kurdistan, 74 km north-northwest from Erbil, 76 km east-northeast of Mosul. Those two wells had to face lots of different drilling hazards especially lost circulation was the limiting factor in the well designs. After the analysis, the theory was gathered to help understanding the problems and find proper solutions. The results of the data analysed was then the basis for the well planning process of Bakrman-3 which will be drilled in the same prospect but far away from the offset wells. The designing process of the well should act as exemplar and practical guideline for complex wells in hazardous drilling environments. The planning included the casing design based on a certain contingency plan mainly due to the geological uncertainty, torque and drag analysis, hydraulic calculations and optimisations and recommendations for the cementing and the working in H2S / CO2 environments.