Active water or light oil is sent downhole through hollow rod to reduce oil flow resistance, thus producing heavy oil from deep formation through screw pump.
利用空心杆向井筒内掺入活性水或稀油，降低油流阻力，实现应用螺杆泵开采深层稠油。
2
With the increase of the anchorage length of the anchor rod, the ultimate pull - out resistance of the anchor rod does not increase linearly, but is less and less obvious by gradual increase.
锚杆随着锚固长度的增加，极限抗拔力并不是线性增加的，而是增加得越来越不明显。
3
Method Large diameter oil tube and weighting rod are adopted to decrease lifting resistance of crude oil and to increase lowering-in energy of the string.