冲砂泡沫流体室内携砂规律研究

摘要

To understand the sand-carrying law of sand washing foam fluid,the relation of sand washing time to sand height,shaft' s dip angle and effects of sand diameter on sand-carrying rate and residence time were studied with the self-made device.The experimental findings show that the sand height first decreases fast,then slowly and finally gently.The sand-carrying rate of sand with a diameter of less than 0.5 mm in foam is greater than 90％.At this moment,shaft' s dip angle basically does not affect sand-carrying rate and residence time.As for sand with a diameter between 1.0 and 1.5 mm,the sand-carTying rate first decreases and then increases,with the increase of the dip angle; the residence time drops with the increase of the dip angle.The sand-carrying rate reaches the minimum when the dip angle is between 45° and 60°.When the dip angle remains the same,the greater the sand diameter,the lower the sand-carrying rate and the longer the residence time.When shaft' s dip angle is different,the movement mode of sand is different.Sand in vertical shaft migrates with foam fluid in an even suspending mode.Sand in inclined shaft migrates in a dancing mode,remarkably sliding toward the lower side.%为了解冲砂泡沫流体的携砂规律,在自制的试验装置上研究了冲砂时间与砂面高度的关系以及井筒倾角和砂粒直径对携砂率和停留时间的影响.试验结果表明,砂面高度首先快速下降,然后缓慢下降直至趋于平缓；直径小于0.5 mm的砂粒在泡沫中携砂率大于90％,此时井筒倾角对携砂率和停留时间基本没有影响；直径1.0～1.5 mm的砂粒,携砂率随倾角的增大先减小后增大,停留时间随倾角的增大而缩短,倾角在45°～60°时携砂率最小.对于相同的倾角,砂粒直径越大,携砂率越低且停留时间越长.垂直井筒中砂粒以均匀悬浮方式随泡沫流体一起运移；倾斜井筒中砂粒以跳跃方式运移,且明显滑向较低一侧.