电缆湿接头在小口径定向孔中的应用

Application of Waterproof Cable Joint in Small Diameter Directional Hole

小口径地质勘探不断向深部发展,受地层条件、孔内事故和孔斜要求等因素影响,很多钻孔需要定向钻进施工。而小口径钻孔一般采用50、60 mm钻具无法满足随钻仪器的下入要求。通过技术攻关及数次现场试验和改进,研制成功了一套小直径电缆湿接头,较好地解决了小通孔钻杆随钻受控定向钻进的关键技术及难点。具体方案为:把测量探管和传输电缆分开,定向测量探管事先与钻具连接,随钻具下放到预定深度,电缆连接信号上接头由钻杆内腔下入,与探管顶部的信号下接头在钻井液中实现电气连接和信号传输,完成定向作业。该方法在国投新集杨村煤矿DF33断层地面探测及注浆工程和莲塘李井田煤炭勘探中进行了试验并成功应用。具有一定的推广应用价值。

Along with the development of small diameter geological exploration and under the influence of formation conditions, hole accidents and hole inclination requirements, more directional drilling construction is needed. In small diameter borehole, the MWD instrument can not be put down through drill pipe of 50 or 60mm in diameter. By technical research, field tests and the improvement, a set of small diameter waterproof cable joint was developed, which solved the key technical difficulty of controlled directional drilling. The concrete steps are as following： separate the measuring probe tube and the transmission cable; connecting directional measuring probe tube and the drill pipe in advance, then put it to the predetermined depth together; through the drill pipe, the top and lower joints being connected in drilling fluid to realize electrical connection and signal transmission to complete the directional operation. This method was tested in ground detection and grouting project in a coal mine of DF33 fault and coal exploration with successful application.