Modeling Coiled Tubing Drag Forces – Small Factors Have a Big Impact

摘要

A significant limitation in the application of coiled tubing technology is the ability of the coiled tubing to push. Push may be required to move a heavy bottom hole assembly (BHA) along a highly deviated or horizontal well. Push may simply be required to push against the drag forces induced by the coiled tubing’s own weight, as it is run into a well. Either way, it is often important to know how far coiled tubing can be pushed into a well, or what weight/length of BHA can be pushed to a certain depth. Accurate modeling is required to avoid a costly mis-run with coiled tubing that fails to get to the necessary depth. Recent projects carried out offshore Brunei illustrate how critical accurate force modeling is and how small well factors can greatly affect the depth that coiled tubing can reach. This paper will also demonstrate how difficult it is to infer down hole drag conditions from surface readings unless the coiled tubing is nearing its point of maximum reach.