Experimental study and dynamic characteristics analysis of partially liquid-filled annulus tubes

• DOI: 10.1371/journal.pone.0209011
• Publication Date: 2018-12-18T18:34:00Z
• Authors: Hongyuan Sun; Ao Zhang; He Li
• Keywords: Annulus (botany); Eccentricity (behavior); Natural frequency

As a useful technology, the horizontal drilling for underground coalmine has been applied in many fields such as gas drainage, water control, exploration and accurate borehole engineering. In this paper, annulus tubes are used to simulate fluid transportation process between rod casing tube when horizontally. The main goal of research is analyze effects eccentricity, velocity, outer length volume fraction on dynamic characteristics partially liquid-filled drillstring system. According Euler-Bernoulli beam model, inner model established respectively considering effect transport inside tubes. Based vibration tube, added mass coefficient proposed calculate natural frequencies And frequency at which system tends oscillate absence any driving or damping force. compared results experiments simulations, depend design parameter (outer length) liquid filled tube. Furthermore, have verified that can be directly calculated from Therefore, it feasible propose method attaching obtain results, concluded that: (i) decrease increases; (ii) increase significantly reduce tube; (iii) velocity eccentricity less (ⅳ) not fixed value, varies with work, models four factors compared, concept reasonable frequencies.