Drilling of a horizontal well to produce petroleum is a task which needs careful planning. The foremost advantage of an openhole horizontal well completion is having the pay zone with the least drilling damage. The first task whether a well can be completed in open hole is by knowing if the formation once drilled is competent enough so that it can remain intact or not. Once the formation is declared and/or proofed to be competent and drilling of the horizontal well is approved there should be enough time to ensure that all equipment and services are going to be available. This study synopsises a brief literature review regarding effects of tool joints during drilling. A diligently planned horizontal well design for Middle East formations is given in this study. The effects of tool joints on the drillpipes are taken into consideration for the calculation of frictional pressure losses in annulus and equivalent circulating density itself. The operational steps while drilling the horizontal well are synopsised in this manuscript, which can be a useful guide for future applications in various petroleum and gas fields. The study also includes frictional pressure calculations for non-newtonian fluids used in drilling operations. The results indicate whether while drilling a horizontal well the fracture gradient of the petroleum reservoir formation is exceeded or not. The study can be improved further by means of considering the effects of temperature on the behaviour of the drilling fluids