Rotary Steerable System With Optimized Functionally Integrated System-Specific Drill Bits Reduces Drilling Days and Extends Laterals in Northeastern US Horizontal Shale Plays

摘要

In the Marcellus and Utica shale plays in the northeastern United States, operators are continually seeking to optimize drilling performance and reduce overall drilling days of horizontal shale wells. This paper describes how several operators have maximized drilling performance and reduced drilling time per well by an average of two days in the Marcellus and Utica shales by adopting a new technology and employing drill bits that are specifically designed for the specific technology and application. The latest fleet of system-specific bit designs has enabled operators to repeatedly achieve more than 4,000 ft of footage drilled in a 24-hr period (well above the average footage per day achieved with conventional BHAs). Most horizontal wells drilled in the Marcellus utilize conventional bent motor BHAs to drill the curve and lateral sections. However, the adoption of a new "pus-the-bit" rotary steerable system (RSS) by some operators has enabled them to reduce overall days per well and extend the length of the lateral sections. The unique aspect of the RSS is the customized complimentary fleet of drill bits designed in conjunction with the RSS, thereby, functionally integrating the bit into the tool. The new custom drill bits used with the RSS incorporate system-specific features to compliment the tool's drilling dynamics and optimize its drilling performance. Bit features such as cutter profile, gage cutter count configuration, polished cutters, cutter exposure and gage pad geometry were developed to improve build-up rates (BURs), rate of penetration (ROP), steerability and durability as well as to mitigate vibrations and any shale-balling tendencies specific to the RSS tool. Through successive bit design iterations, drilling performance with the RSS has steadily advanced with every horizontal job by reducing days spent drilling the curve and lateral sections. This paper will present increased efficiency and monetary savings from the development of drill bits carried out in parallel with improving the RSS drilling system. The paper will show the improvements in comparison to offset wells and highlighting the money saved and reduced non-productive time (NPT).