Drilling High-Angle Casing Directionally Drilled Wells With Fit-for-Purpose String Sizes

Abstract

TX 75083-3836, U.S.A., fax 1.972.952.9435. AbstractThis paper discusses the design and testing of 10 ¾-in. and 7 5/8-in. casing directional drilling equipment and procedures that ConocoPhillips plans to use on a mature North Sea asset. ConocoPhillips has worked with Tesco Corp. and Schlumberger in building the tools necessary to complete this task. These include: downhole casing drilling tools, underreamers, positive displacement motors, MWD tools, rotary steerable systems (RSS), and high capacity winches for this work. Testing this equipment in commercial North Sea operations is prohibitively expensive. Therefore, tests were conducted at a drilling test facility near Cameron, Texas, where operations were conducted over a wide range of rotating speed, weight and flow conditions as well as inclinations from vertical to horizontal. High frequency surface and downhole drilling mechanics measurements were made that allowed for diagnosing problems and improving the systems.