绳索取心钻进技术在松散盐岩地层中的应用探讨

Discussion on the Application of Wire-line Coring Drilling Technology in Unconsolidated Salt Strata

摘要:

地质岩心钻探中，岩心采取率一直是地质找矿、地学科研工作者重点关注的对象，也是岩心钻探重要的考核指标。传统的钻探取心方法在松散、软弱、含盐地层，特别是含易溶盐地层的取心质量不佳；绳索取心钻探在完整地层取心效果较为理想，同时可大大提高劳动生产率、降低劳动强度，而对于松散、软弱地层，其取心难度比起传统钻探有时更为复杂。通过柴达木盆地达布逊干盐湖科学钻探工程，对钻遇的地表层、松散地层如何采取技术方法提高岩心采取率进行了探索和研究。实践证明，通过改善冲洗液性能、改进取心卡簧特性及钻头出水方式3个方面技术措施，可大大提高绳索取心钻进在松散、软弱、弱固结、含盐地层的岩心采取率，由改进前的平均30%提高为平均96%。

Abstract:

Core recovery has always been focused on in geological core drilling, which is also an important evaluation index for core drilling. It is difficult to have good core quality by traditional core drilling method in loose, soft and salt formations, especially in those formations containing soluble salt. By the use of wire-line coring drilling, ideal coring effect can be achieved in complete formation; at the same time, the labor productivity can be greatly improved with labor intensity reduction. For the loose and soft layers, coring drilling is sometimes more difficult than traditional drilling. Taking the case of scientific drilling project in Dabuxungan salt playa, exploration and research were made on how to improve core recovery in the drilled surface layer and loose layer. The practice proved that wire-line core recovery can be largely improved in loose, soft, unconsolidated and salt bearing formations by the improvement of flushing fluid performance, property of core lifter and bit water way. The average core recovery is raised from original 30% up to 96%.