A case history will be presented on the use of synthetic oil based muds as completion fluids for horizontal wells. The subject wells were located in the UK North Sea at ChevronTexaco’s Captain field. The 5000 - 6000 ft horizontal wells in this field were completed with stand alone screens using a cleaned synthetic oil based mud. The completion fluid used was the mud used to drill the horizontal section screened over 270 or 325 mesh screens. The presentation will deal with pertinent field background information, completion procedures, completion fluid properties, well productivity results, remedial treatment used and conclusions.