Spud to Reservoir—With Casing While Drilling (CWD)/Polycrystalline Diamond Compact (PDC) Drill-out Technology Using an Automated Drilling Rig

Abstract

AbstractThe first well drilled on any newly commissioned rig is fraught with challenges. This paper describes how these challenges were met with the successful introduction of Casing while Drilling (CwD) and polycrystalline diamond compact (PDC) drill-out bits, employed over the entire length of a vertical exploration well.The operator planned to drill a 12 1/4-in. hole from surface using a CwD bit conveyed on 9 5/8-in. casing. The intermediate casing (7-in.) would also include a CwD bit to ensure casing was set at the correct depth. The intermediate hole (8–1/2-in.) and reservoir section (6-in.) would entail drilling-out the previously run CwD bits and then continuing to drill to section Total Depth (TD).CwD and PDC drill-out technologies were used to successfully drill from surface down into the reservoir (2,418m total length). CwD was used to drill and simultaneously case the 12–1/4-in. hole section with 9 5/8-in. casing to a depth of 780m. The 8 1/2-in. bit drilled-out the 12 1/4-in. CwD bit and drilled on to section TD at 2,075m. The 7-in. casing with an 8 1/2-in. CwD bit was successfully set at depth even though the casing stood up at 1,924 m and had to be drilled to bottom using the CwD bit. A 6-in. PDC bit successfully drilled out the 8 1/2-in. CwD bit and continued on to drill to 2,418 m. The well was completed and suspended inside the budget Authorisation for Expenditure (AFE).This was the first well drilled with a newly commissioned state-of-the-art semi-automated drilling rig using CwD and PDC drill-out technology. The well included the first CwD run in the Netherlands. The 12 1/4-in. CwD run was the longest run in the Eastern Hemisphere with this system, drilling from surface to 780 m. The first 2,418 m (90%) of the well was drilled with CwD and PDC drill-out technology. Included in this paper are the application, technologies involved, results and lessons learned. It also summarises the performance witnessed on the second well using the same methodology.