Currently the options for directional drilling of larger hole sizes, such as those greater than 6", with Coiled Tubing Drilling (CTD) are limited. This paper introduces a new system that utilizes a 5.0" BHA with a Rotating Orienter. The BHA is the first drilling tool to utilize a solid state MEMs gyro for directional measurement at all inclinations from vertical to horizontal. This paper aims to show that the use of this type of tool in combination with a Hybrid Drilling Rig can provide a technically and economically feasible alternative, which could expand the size of the CTD market.

The paper reviews a 5-well drilling program that has been carried out in order to assess the capabilities of the tool and the drilling techniques used. The 5 wells consist of directional and horizontal profiles and both mud and an air mist were used as the drilling fluid. Details of the equipment used, the performance of the tools and lessons learnt from the operations are all provided.

All initial aims of the project were met with the tools reaching the target zone on all wells. Accurate, reliable and efficient drilling was demonstrated, whilst drilling hole sizes ranging from 6.25" to 8.5".

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