自水平井技术发展以来，人们就开始了分支井钻井的尝试。所谓分支井钻井，就是从一个主井眼中侧钻出多个分支井眼的钻井，而主井眼可以是直井，也可以是水平井。主井眼为直井的分支井可以开采不同的油气层，相当于多口开发不同层位的定向井或水平井，能有效开采多层段的油气藏 Since the development of horizontal well technology, people began to try to branch wells. The so-called branch well drilling, that is, from the side of the main borehole drilling a number of branch shaft drilling, and the main borehole can be a vertical well, it can be a horizontal well. The main wellbore is a vertical well whose branch wells can exploit different hydrocarbon reservoirs, which is equivalent to the multi-directional development of directional wells or horizontal wells with different layers, and the effective exploitation of multi-layer reservoirs