Electric Coiled Tubing Drilling - The First Steps Toward a Smart CT Drilling System

Abstract

This paper describes a joint industry project to develop an electrically powered bottom hole assembly for use in coiled tubing drilling (CTD) applications. Phase I of the project, recently completed in Aberdeen, produced a highly successful prototype assembly that recorded over 190 hours of drilling time without failure. Whilst the prototype was made almost entirely from existing technology, the success of the test has generated confidence to develop a more fit for purpose' motor. A system overview explains the concept behind, and the advantages of, electric coiled tubing drilling (ECTD). The bottom hole assembly is described in detail, along with various surface components and the electrical power transmission system. The testing program and operational procedures are outlined, together with some of the key results. The development plan for the technology is reviewed to highlight the ultimate goal of producing a smart' drilling system. It is envisaged that, based upon feedback from near-bit sensors, such a system would be able to automatically adjust certain parameters to optimize drilling performance. The paper concludes that electric coiled tubing is a feasible and practical alternative to conventional CTD, although there are certain technological barriers that must be overcome. P. 61