零半径水射流径向钻井技术的研究与应用

新型水射流径向钻井技术以零半径(套管外)从现有井筒内径向钻入地层,可为老油田、边际油田、低渗透油气藏和煤层气开发提供一种能有效恢复或提高单井产量的经济手段。采用集成式井下工具的水力深穿透技术,水平钻孔长度可达2m,能有效穿透近井带污染区,用定向穿透辅助压裂可有效改造低渗透裂缝性油藏。采用分步作业方式的水射流钻径向分支井技术,利用连续管起下钻具,水平钻孔长度可达20～50m或更长。最后指出喷嘴的牵引能力和钻孔性能是对水平钻孔长度及适应地层范围影响最大的关键因素。

Research and application of the zero-radius water jet radial drilling technology

The new-type water jet radial drilling technology conductsa radial drilling into the formation from the present wellbore outside the casing. It can provide an economical method for effectively recovering or improving per-well production rate in development of old oilfields,marginal oilfields,low permeability oil-gas reservoirs and coal-bed gas. Adopting the hydraulic deep penetrating technology which utilizes the integrated wellbore tools,the horizontal boring length can reach 2 m,with an effective penetration of the pollution zone near the well. Adoption of oriented penetration and auxiliary fracture can effectively reconstruct low permeability fissured oil reservoirs. The water jet drilling radial branch well technology characterized by step-by-step operation mode,together with the technology of using the coiled tubing to trip the drill tool,can make the horizontal boring length reach 20 to 50 m or even longer. The constitution of the technological equipments and operating techniques are introduced in this paper and the major factors influencing the technical parameters and the scope of application are also discussed.