Abstract
There are some problems in coiled tubing drilling in deep horizontal wells, such as large buckling friction and difficult extension drilling. At present, a friction reduction tool based on Coanda effect is used to improve the problems existing in coiled tubing drilling. However, there are few systematic studies on the working characteristics of the tool, and the tool power matching is poor. Therefore, based on the basic theory of wall attached jet, the numerical model of friction reducing tool is established. The effects of the working parameters (inlet flow rate, drilling mud density) and the structural parameters (thickness of the flow channel, outlet diameter) on the working characteristics of the tool are analyzed. The results show that, the working pressure drop increases with the increase of working parameters, and decreases with the increase of structural parameters. The cleft tip, vortex chamber and outlet are vulnerable to erosion. The erosion rate is positively correlated with the working characteristics. Among them, the inlet flow rate has the most significant effect on the working performance and erosion rate of the tool. The research results provide a theoretical basis for the field application and parameter selection of friction reduction tools.
NSTL
Elsevier