Shell has targeted casing and liner drilling as one of five mature technologies for an accelerated uptake within its group E & P companies. A 9 5/8" surface casing drilling job performed onshore Brunei in September 2003 utilized a new design of casing drill shoe that extends the depth range of rotary casing drilling. The convertible drill shoe has a novel feature that allows the cutting structure and blades to be extruded outwards once section TD is reached. By this process, the drill shoe converts to a cementing shoe, allowing the casing to be cemented in place. The cementing shoe and next hole section can then be drilled without interference from the casing drill shoe cutting structure and blades. Application of the extrusion process allows a more aggressive and durable cutting structure on the casing drill shoe and hence allows deeper, more resistant formations to be drilled.
The paper will describe the planning, implementation and subsequent results from this world’s first convertible casing drill shoe job that led to a world record depth achieved for this type of rotary casing drilling, and a cost effective option for setting vertical surface casings.