The evolution of casing while drilling (CwD) illustrates the economic, efficiency and health, safety and environment benefits achievable with the seamless integration of downhole tools and surface drilling equipment. However, several technology gaps have restricted CwD from reaching its full potential to optimise the well construction process.
This paper describes the integrated development and application of a retrievable Enhanced Casing Installation (ECI) system, engineered to take directional (Level 3) casing drilling technology to another level and further expand the functionality of both specialised and standard land drilling rigs. The system, which enables directional drilling with composite casing and standard mud motors, differs from typical Level 3 CwD methodologies in that the composite option allows bottom hole assembly (BHA) placement inside the shoetrack, thus helping reduce vibrations and wear on the reamer and other downhole tools. Along with increased well stability and allowing simultaneous logging/measuring while drilling, the ECI device is configured with a comparably lightweight BHA, requiring fewer components, such as jars and roller reamers, making it easily retrievable with cable. As discussed, the cost-effective integration of downhole and surface equipment is clearly reflected in the capacity to rerun the retrieved bit and reamer – a marked difference between the sacrificial bits required for the commonly used Level 2 (vertical) CwD technique.
Moreover, the authors will present results of a specialised test stand evaluation and subsequent field trial, where the system was integrated on a fit-for-purpose rig and used for casing drilling at a 45° angle with the BHA pulled intact from 1800 m MD.
