套管欠平衡一体化钻井技术在老油田的钻进试验表明,该技术不但可以成功钻进不同压力层,还可达到如下效果:1)使钻进引起的地层伤害减到最小并取得最大注入能力;2)使诱导性漏失减到最小,从而减少了压差卡钻;3)减少了油井准备、起下钻柱和下套管等非生产作业时间,提高了钻进效率。若使用地面闭环加压分离系统来控制流体和压力,再应用该钻井技术钻井,和常规钻井技术相比,还具有以下优点:1)下套管柱 Bored underbalanced drilling technology Drilling tests in old fields show that this technique can not only successfully drill into different pressure zones but also achieve the following effects: 1) Minimize formation damage caused by drilling and achieve maximum injection Ability; 2) minimize induced leakage, thereby reducing the pressure differential stuck; 3) to reduce the preparation of the well, from the drill string and under casing and other non-production operations, improve drilling efficiency. If the ground closed-loop pressurized separation system is used to control the fluid and pressure, and then drilling using this drilling technology, compared with conventional drilling technology, has the following advantages: 1) The lower casing string