剪切帽技术对PDC切削齿的保护原理及应用

套管开窗侧钻施工或套管钻井结束后,需要使用专门的钻头或磨铣工具磨铣套管或钻穿浮鞋、套管钻头等套管组件,然后才能进行后续地层的钻进。传统工艺是采用两趟钻或一趟钻完成,两趟钻浪费时间和成本,一趟钻对PDC切削齿的伤害较大。Varel钻头公司研发的剪切帽技术,其原理是在套管开窗或钻穿浮鞋、套管钻头等套管组件时可提供剪切作用,同时保护主PDC切削齿面。进入地层后,剪切帽快速磨损脱落,使切削齿高效钻进地层。现场测试结果表明,剪切帽可有效保护PDC切削齿不受损坏,提高机械钻速。介绍了剪切帽技术原理及其现场测试情况,以期推动我国用于套管开窗和套管钻井施工的一趟钻系统的发展。

Protecting Principle of PDC Cutter Technology Using Shearing Cap and Its Application

When the window milling operation or casing drilling is over,to drill the next section of the wellbore,the casing or casing component such as casing drill bit and float equipment must be drilled out by using specially designed drill bit or milling tool.Traditionally,this is done by using two trips or one trip.With the two trips,additional time and costs are required,while the one trip has the potential to damage the PDC cutters.Varel International developed shearing cap technology,the technology provides a shearing action during the window milling or casing component such as casing drill bit and float equipment drill out process while protecting the primary PDC face cutters.Once in the formation,the shearing caps wear away quickly to expose cutter in virtually pristine condition.Field testing result shows that shearing cap can effective protect PDC cutter from damage and improve rate of penetration.In this paper,the technology principle and field testing situations are presented in order to promote the development of our country's single trip system used for window milling and casing drilling operation.