PDC钻头落井打捞方法分析与应用

随着PDC钻头的广泛应用，同样面临很多复杂的钻井问题，钻头落井问题尤为棘手。如果钻头落井事故处理方法不正确，将造成工期延误，甚至报废井眼等后果，造成巨大的经济损失，寻找能够保证PDC钻头打捞成功率的打捞方法刻不容缓。文章提出适用于井底钻头歪斜、不居中等复杂情况的两趟钻打捞技术，显著提高了打捞成功率，并深入分析了传统PDC钻头落井打捞方法，明确传统的磨铣、公锥打捞方法对常规落井钻头打捞的可用性。首先引鞋扶正、引导落鱼，通过旋转将钻头转活并居中，提高捕捉落鱼的成功率；然后利用改进的打捞工具“一把抓”将落鱼捞出。通过应用此技术，成功将渤海地区某油井落井PDC钻头打捞出井。实践表明，该两趟钻打捞技术，可保证PDC钻头打捞成功率，大幅缩短作业工期，降低成本，同时为后续钻头打捞作业提供参考与借鉴。

The Analysis and Application of Salvage Method for the Fallen PDC Bit

With the wide application of PDC bit, facing with many complicated drilling problem, the drill bit falling accident is particularly serious, so it is very urgent to find a salvage method that can ensure the success rate of PDC bit salvage. This paper proposes two-drill salvage technology, which is especially suitable for the fallen drill bit in skew in the wellbore, which significantly improves the success rate of salvage; besides the paper has deeply analyzed the salvage method of the fallen drill bit to clear that the traditional mill and tap salvage method is effective for the conventional fallen drill bit. Firstly, the guiding shoe adjusts and guides the crooked drill bit to the middle of the well bore, mainly by rotating to drive the drill bit and improve the success rate of catching fallen drill bit; secondly, the improved salvage tool takes the fallen drill bit out. By using this technique, the fallen PDC bit of an oil well in Bohai sea area was successfully recovered. Practice indicates that the two-drill salvage technology can ensure the success rate of PDC bit salvage, and obviously shorten the operation period and reduce the cost, besides the successful salvage work for the fallen PDC bit will provide reference for the follow-up drilling work.