Performance Step Change: 3 Years of Advances in CNS Britannia Field, UK

摘要

This paper describes advanced PDC technologies applied to the challenging 12-1/4 inch section in the Britannia field in UK Central North Sea (CNS) that significantly reduced the number of bit trips and associated drilling costs. The 12-1/4” section is generally drilled in three main intervals with RSS/PDM. New PDC bit technology was developed to efficiently drill two of these sections with controllable torque response and consistent directional behavior while achieving maximum ROP and durability. Several new bit designs were implemented and tested at the manufacturer’s surface simulator with good results. The upper interval from the 13-3/8” shoe originally used 8-bladed 13mm cutter PDC down to the Maureen limestone (USC c.15,000psi). A 19mm 7-bladed PDC featuring reduced exposure and advanced cutter technology was introduced. This design achieved a drilling record from the 13-3/8” shoe to the top Tor in one run where previously two bits had been required. In addition there was improved steerability on a motor through the Lista Formation; previously this had been considered directionally challenging. The same section on the next well with this bit design achieved a field footage record of 9,534ft.