The first application of coiled tubing (CT) occurred during WWII in a project named PLUTO (pipeline under the ocean). It involved the placement of a continuous pipeline on the seafloor across the English Channel. The pipeline was constructed using smaller individual sections of tubing welded together coiled into a large spool of continuous tubing. Though the project had limited success, it set the stage for further exploration into this new technology. Industry professionals pursed the development of CT with the hopes of it becoming an effective intervention tool for safe and effective work-over operations on wells. By 1962, the California Oil Company and Bowen Tools reached this goal and became the first company to successfully develop the
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Yet, CT primarily serves as a tool for well workovers and other well maintenance services. Since CT revitalization in 1991, CTD has developed enough to become a viable alternative to conventional drilling in certain situations because of its tremendous time reduction incentive (Leising and Newman, 1993; Yang …show more content…
The central advantage of CTD is its ability to drill underbalanced (closed wellbore) safely. Underbalance drilling results in extremely high rates of penetration not attainable in conventional rotary drilling providing a major reduction in overall rig time. Drilling underbalance also increases drilling bit performance and does not run the risk of inflicting formation damage during formation penetration (Kumar, 2011).
Another great asset of CTD is the elimination of the repetitive process of making connections (periodically connecting sections of drill string together). Incidentally, the time need for tripping in and out during operations is significantly reduced when using a continuous spool of drill pipe. Tubing can simply be wound up; it does not require a section-by-section disassembly and re-assembly when tripping. Additionally, making connections requires intermittently interrupting circulation within the wellbore increasing the possibility of creating a build-up of cuttings within the wellbore from particle settling. With CTD, continuous circulation can be maintained at all times (Yang,
Yet, CT primarily serves as a tool for well workovers and other well maintenance services. Since CT revitalization in 1991, CTD has developed enough to become a viable alternative to conventional drilling in certain situations because of its tremendous time reduction incentive (Leising and Newman, 1993; Yang …show more content…
The central advantage of CTD is its ability to drill underbalanced (closed wellbore) safely. Underbalance drilling results in extremely high rates of penetration not attainable in conventional rotary drilling providing a major reduction in overall rig time. Drilling underbalance also increases drilling bit performance and does not run the risk of inflicting formation damage during formation penetration (Kumar, 2011).
Another great asset of CTD is the elimination of the repetitive process of making connections (periodically connecting sections of drill string together). Incidentally, the time need for tripping in and out during operations is significantly reduced when using a continuous spool of drill pipe. Tubing can simply be wound up; it does not require a section-by-section disassembly and re-assembly when tripping. Additionally, making connections requires intermittently interrupting circulation within the wellbore increasing the possibility of creating a build-up of cuttings within the wellbore from particle settling. With CTD, continuous circulation can be maintained at all times (Yang,