Kuwait has been drilling and producing from the deep, sour Jurassic reservoirs in the West Kuwait area during the past 25 years. The wells, which are mainly vertical, penetrate heavily fractured, highly pressured reservoirs and produce high quality light oil. New wells are planned to be added with more complex deviated and horizontal well profiles, in an attempt to intersect multiple fractures and fracture swarms.
Selective production has contributed to the depletion of certain reservoir intervals, which in addition to the pressure reversals in the lower reservoirs and their fractured nature presents increased complications and challenges to the drilling of these wells. The difficulty of drilling such depleted / fractured formations has presented the operator with new and complex challenges, especially in deviated and horizontal wellbores. These include partial / total losses, gas kicks, and mechanical / differential sticking, resulting in some instances in having to sidetrack the wellbore.
A case history of two recent West Kuwait directional wells, DF-15 and MN-159, is presented to explain the nature of the problems that have been encountered and the solutions that were successfully developed to handle them. The challenges of drilling in these environments were analyzed, with practices and materials being developed and adapted to enable drilling to continue through these troublesome zones. The new solutions and methodologies provide a basis for future optimization in subsequent wells.