复合材料桥塞卡瓦试验研究

Experimental Study of the Bridge Plug Slip of Composite Material

目前常用的各种规格的金属桥塞普遍存在易卡钻以及钻铣困难等缺点,为此,试验研究了复合材料桥塞卡瓦。该卡瓦采用热固性树脂基复合材料模压制作,满足了页岩气井用桥塞的各项指标要求,实现了桥塞整体"无金属化"。研究结果表明,镶嵌碳化硼牙齿的复合材料桥塞适用工作压差为35 MPa,镶嵌氧化铝牙齿的桥塞适用工作压差为50 MPa,陶瓷牙齿在卡瓦上的最佳镶嵌角度为18°。碳化钨牙齿虽然强度很高,其桥塞承载破坏为复合材料卡瓦本体破坏,碳化钨牙齿无损伤,但其密度太大,磨铣困难且容易卡钻,因此不适合用作该复合材料桥塞嵌件。

At present there are universally some weaknesses with frequently used metal bridge plugs of different specifications, such as easy drillpipe sticking, and hard to drill and mill. Therefore, an experimental study of com- posite bridge plug slip was conducted. The easy-to-drill composite slip was produced through mould pressing using thermosetting resin matrix composites, satisfying the index requirements of bridge plugs for shale gas well and avoi- ding use of metal for the bridge plug. The research findings show that the suitable operating pressure difference for composite bridge plug inlaid with boron carbide tooth is 35 MPa; that for the plug inlaid with aluminum oxide tooth is 50 MPa. The optimum inlaying angle of ceramic tooth on slip is 18~. The tungsten carbide tooth is high in strength, but the composite slip body of the plug with these teeth may be damaged. There is no damage to the teeth themselves, but they are fixed too dense that it is difficult to mill and it is easy to get stuck. Therefore, it is not suit- able to use the tungsten carbide tooth as the insert of the composite bridge plug.