In article 10.43 of SY/T 53 13-93 "drilling engineering terminology", dogleg is defined as the angular change of borehole axis per unit interval length in three-dimensional space, and the unit interval length depends on the needs of inclinometer in production practice. It includes both the change of inclination angle and azimuth angle. Commonly used "/100 m". The bending of pipe rod caused by dog leg reduces the freedom of drill pipe, and the stress will be released centrally, which will make the fixed valve open in the next stroke, causing leakage and reducing pump efficiency. Too large dogleg will cause serious friction between drill string and borehole wall, and metal will consume a lot of energy in the process of friction, which will increase the difficulty of drilling and oil production and easily lead to downhole accidents.