节水钻探系统井下工况判断水力模型

Hydraulic Model for Downhole Drilling Condition Judgment with Water-saving Drilling System

节水钻探是基于解决干旱地区和漏失地层钻探严重缺水问题而发展起来的一项最新技术,其通过实现钻井液的孔底局部循环,使钻进过程中的用水量降为原来的5%～20%。节水钻探系统在使用过程中,由于孔内不返水,在地表只能通过观察压力表的变化量来判断孔内工况,精度不高。通过研究,最终解决通过地表压力变化值来判断孔内工作情况的量化问题,建立初步理论模型,从而更加准确地判断孔内的工况,使这套钻具更快地应用到实际工程中。

Water-saving drilling system is a newest technique, which was developed to deal with the serious water scarcity for drilling in arid area and leaking formation. The water consumption in the drilling process was only 5% - 20% of the original amount by drilling fluid local circulation at downholc. In the application of water-saving drilling system, in-hole drilling condition can only be judged by observing pressure change in pressure gauge on the surface with low precision. By study, the quantization of working condition in the hole could be observed through the surface pressure variation value and the preliminary theoretical mode was established to have more accurate judgment on in-hole drilling condition.