CACT-OG is a joint operating company consisting of CNOOC, ENI, and Chevron as its Principal Companies. CACT- OG is the operator of Huizhou HZ 25-4 oilfield in South China Sea, which was discovered in December of 2005 as multiple oil bearing zones found in the vertical exploratory well drilled by a semisubmersible rig. HZ 25-4 field is located in block 16/19 in central area of Pearl River mouth basin, located 6 km southwest of the HZ 19-2 platform in a water depth of 102 meters. After discovery, extensive studies were conducted for the development of this field. It was decided to upgrade the existing drilling rig on the nearby HZ 19-2 field platform and drill extended reach (ERD) wells from the platform. Three of five ERD wells were drilled and completed with 6" horizontal laterals and stand alone screens for sand control. A number of challenges appeared while drilling these wells including: ERD drilling experience level, excess torque and drag, hole instability, hole cleaning and resulting pack off, high side force and casing wear, high ECD due to shallow TVD, losses due to high ECD and fault encounter, and shock and vibration. The result of these challenges was long times to complete the wells and excess budget overruns. After the completion of the third well, it was been decided to suspend the operations and perform detailed analysis on the challenges with extensive lessons learned in order to approach the remaining two ERD wells in the Plan of Development with a different strategy. Following the studies and drilling analysis, the revised final plan included a new engineering design, revised operations procedures and monitoring, new approach for team building and training, and implementation of newer technologies such as utilization of Aluminum Drill Pipe and Continuous Circulating Devices. The result of the new plan applied has been a dramatic improvement in performance and consistent savings in budget. It has been observed that this different drilling approach and technology has opened a new window on how to drill challenging ERD, and that is a key to improved drilling performance.