CANADIAN COILED TUBING HORIZONTAL DRILLING - TECHNOLOGY AND APPLICATIONS

Canada has played a prominent role in the development of horizontal dr illing technology. To date, over 1,400 ''grassroots'' and ''re-entry'' wells have been drilled. Although other countries have experienced gr eater numbers of wells, the number of different types, varieties, and formations tested with this technology in Canada is unparalleled. Due in part to the exponential growth of horizontal well applications sinc e the mid-1980's, coiled tubing (CT) technology in Canada has been ada pted and evolved for more traditional uses such as horizontal well sti mulation, evaluation, workovers, and clean-outs. The principal nontrad itional aspect of CT is its use in drilling operations. This paper wil l deal with the current state and recent advances in CT horizontal dri lling in Canada. A brief historical perspective will be presented that highlights Canada's presence as a pioneer in CT drilling and document s its evolution from vertical re-entries dating back to 1974, grassroo ts vertical wells in 1976, to the industry's current efforts at vertic al and horizontal CTD. The principal Canadian service companies are re viewed in terms of present capabilities in CTD applications and the pe rceived driving forces that are stimulating the development of this em erging technology. The key factors such as diameter and fatigue life o f the coil, length limitations, bottom hole assemblies, surveying meth ods and the economic and market factors affecting CTD relative to more conventional drilling techniques are reviewed. Finally, the future te chnological, market and economic developments necessary for the succes sful implementation of CTD for grassroots vertical and horizontal well re-entry projects are suggested.