Abstract This paper presents the results of a five-well extended reach drilling (ERD) sidetrack program in offshore California. The challenges of drilling the ERD sidetracks were compounded by potential drilling hazards, the limited capability of rig equipment, and extensive activities required to restart a cold stacked platform rig. Despite these challenges, the program was delivered 138 days ahead of schedule and 44% under budget. This case history describes the key elements of the project that contributed to execution success, including:Early identification of technical challenges and solutionsPlanning processes that ensure alignment across functionsAn active goods and services quality initiative to maximize equipment reliabilityIncorporation of key learnings from other teams around the worldContinual redesign from well to well based on lessons learned during the execution phaseTechnical solutions that balance potential risk and reward Specific cold start and ERD sidetrack practices are discussed, as well as the work processes that were effective in establishing a mindset of continuous improvement and flawless execution. Introduction Due to the significant cost of drilling, it is critical to apply a rigorous and disciplined approach to planning and execution. Maintaining a mindset of flawless execution facilitates improved performance by identifying optimization opportunities while balancing potential risk exposure (Newman 2005). The success of the operator's platform drilling campaign can be attributed to having the right team of people in place using proven planning and execution processes. These processes drove an understanding of the technical challenges and potential solutions early in the project, and ultimately delivered a five-well ERD sidetrack program ahead of schedule and under budget. Field Overview The Santa Ynez Unit (SYU) is located approximately 20 miles west of Santa Barbara, California. Operations in SYU comprise an oil and gas processing plant at Las Flores Canyon and three offshore platforms located in federal waters in the Santa Barbara Channel, as illustrated in Fig. 1. The three production platforms (Hondo, Harmony, and Heritage) range from 5 to 9 miles offshore and lie in water depths of 850, 1,200, and 1,075 ft, respectively. Each platform has a company-owned drilling package installed. All electricity for the drilling and production equipment is generated onshore and transmitted offshore through subsea power cables. The oil and gas produced offshore is transported through subsea pipelines to the Las Flores Canyon processing plant. These fields produce primarily low-gravity 12- to 20º-API sour crude from the highly fractured Monterey chert formation (Walker 2008).