双壁钻杆在空气潜孔锤反循环钻进中的应用研究

Application study of dual-wall drill pipe on DTH reverse circulation drilling

针对现有压力计算模型难以满足指导大直径潜孔锤反循环钻进所需双壁钻杆选型工作的问题,采用现场对比试验方法,在最大注气量为35 m3/min、额定工作压力为3 MPa的空压机设备条件下,依托多个钻井工程项目,对Φ127/70 mm双壁钻杆、Φ178/113 mm双壁钻杆分别进行了2组试验。结果显示:Φ127/70 mm双壁钻杆压降大,孔深至197.5 m时注气压力已达到3 MPa;Φ178/113 mm双壁钻杆压降小,孔深至295 m时注气压力仍不超过1.3 MPa。试验表明,Φ178/113 mm双壁钻杆排渣能力强,更适合大直径潜孔锤反循环快速钻进工艺。

For the problem that the existing pressure calculation model is difficult to meet the double-wall drill pipe selection guidance work of large diameter DTH reverse circulation drilling, field contrast test method was adopted under the condition of air compressor with maximum gas injection volume of 35 m3/min and rated working pressure of 3 MPa; two groups of tests were carried out on Ф127/70 mm double-wall drill pipe and Ф178/113 mm double-wall drill pipe. The results show that： Ф127/70 mm dual-wall drill pipe has a large pressure drop, the gas pressure had been reached 3 MPa when the hole depth was 197.5 m,while the Ф178/113 mm dual-wall drill pipe had a small pressure drop,the gas pressure had not still exceeded 1.3 MPa when the hole depth was 295 m. It indicates that Ф178/113 mm dual-wall drill pipe is more suitable for large diameter DTH reverse circulation drilling with fast slagging capacity.