Drilling extended lateral sections to maximize reservoir exposure is key to optimizing field productionand data recovery. However, it presents peculiar challenges not limited to hole-cleaning, wellbore stability,narrow drilling windows, and excessive torque and drag. Thus, customizing the fluid system to drill lateralsections requires information to understand the formation characteristics, including geomechanical data todetermine the correct mud weight window, a precise selection of optimal fluid rheological properties, goodinhibition, and lubricity, which are of foremost importance for extended-reach drilling (ERD) wells. The reservoir section of the well presented in this paper was previously drilled unsuccessfully twice, asthe targeted zone was not reached. During the drilling phase, a large amount of non-productive time (NPT)was observed due to stuck pipe incidents, hole collapse, and then, hole cleaning issues were encounteredwhile drilling. Another critical concern is the narrow mud weight window range, which causes the formationto break when Equivalent Circulating Density (ECD) increases beyond the pore pressure or fracture pressureof the formation. A new generation of High-Performance Non-Aqueous Based Mud (HPNBM) was engineered to drillthese types of complicated, long horizontal intervals matching the drilling performance required to drillsuch sections and deliver a perfect gauge hole. This HPNBM provides high shear-thinning properties, anexcellent low-end rheological profile, and rapid-set/easy break gels. This paper presents a successful welldelivery of drilling the longest horizontal section in the country within a record amount of time. The previousattempts were carefully studied to identify the challenges associated during drilling and considered whiledesigning this HPNBM. The high-performance non-aqueous based mud system proposed with stress cagingtechnique was successful, economic, and drilled successfully with zero non-productive time (NPT) relatedto drilling fluids. Engineering software was utilized as hole cleaning is critical for drilling the horizontalsections to reach the targeted depth and run casing to the bottom. This paper presents the longest horizontal section (4,200 ft) to be drilled to the targeted depth asplanned in Turkey. A comprehensive analysis that includes the planning phase, application, techniques, andperformance of the mud system will be presented.
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