Woodford Shale of Oklahoma is emerging as one of the fastest growing natural gas fields in North America because it has all the characteristics required for a profitable shale-gas play. More than $2 billion were spent in 2008 on some of the major productive intervals in this field. Although the upside potential is tremendous, efficient extraction of natural gas from the Woodford Shale poses several drilling and completion challenges. Low porosity and permeability limits well productivity. Complex well profiles and extended length laterals are required to maximize productivity. Long laterals posed several drilling challenges such as excessive slide drilling time, difficulty controlling well trajectory, unacceptably low penetration rates, high torque, and high drag. Engineers determined that wellbore tortuosity and high friction factors caused inefficient transfer of weight on bit and reduced rate of penetration (ROP). Existing rotary steerable systems available are typically cost prohibitive for this application/environment. To overcome these challenges, research, field testing and several years of experience gained with other automated rotating and non-rotating rib steering systems has culminated in the development of a new state-of-the-art rotary steerable closed-loop system (RCLS). This system, specifically designed for 3D wellbores for rotary steerable directional drilling in low spread cost land-drilling applications uses an automated rib-steering closed-loop system. Since the introduction of this innovative system, many wells have been drilled in North America with build/drop of 8°/100 ft. Bottomhole assembly (BHA) modeling software with finite element analysis was used to optimize BHA design. This strategy has been implemented to drill several wells in the Woodford Shale with excellent results. The new design of RCLS coupled with advanced BHA modeling software has significantly improved the drilling performance. The results achieved are excellent control over the well trajectory in the curve and lateral, improved transfer of weight to the bit, minimum torque and drag. Drilling complex well profiles have increased the length of laterals by several hundred feet. This has enabled additional recovery of gas, and the days required to drill the lateral interval have been reduced by more than five days.
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