CQ-EMWD电磁波随钻测量系统

CQ-EMWD System

电磁波随钻测量仪(EM-MWD)采用低频电磁波作为信号载体,信号传输不依赖钻井循环介质,可用于气体钻井、欠平衡钻井、井漏复杂井。但低频电磁信号在地层中传输受地层电阻率影响较大,信号衰减较快,导致随钻测量垂深一般不超过3000m,限制了推广应用。为此,攻关开发了低频电磁信号自适应高效发射技术、微弱信号接收及解码技术、高抗振测量技术和"测量总成+中继电缆+发射总成"模块化接力传输技术,研制了CQ-EMWD电磁波随钻测量系统,并在气体钻井、欠平衡钻井、水基钻井液及油基钻井液中试验应用21口井。该系统测量垂深达到4326m,解决了气体、欠平衡钻定向井、水平井随钻测量技术瓶颈和井漏复杂井随钻测量难题,为钻井提速、提效和降低随钻测量费用提供了良好的技术支持。

Electromagnetic measurement while drilling （EM-MWD） system uses low frequency electromagnetic wave as signal carrier and does not depend on drilling cycling medium for signal transmission. It can be used for gas drilling, underbalanced drilling and complicated well status. However, low frequency electromagnetic signal, when transmitted in formation, is easily affected by formation resistivity, leading to a fast attenuation of the signal. As a result, the vertical depth of MWD is usually less than 3000 meters. A series of technology is developed for settlement of this problem, such as low frequency electromagnetic signal efficient emission technology, weak signal reception and decoding technology, high anti-vibration measurement technology and “measuring assembly ＋ relay cable ＋ emission assembly” modular relay transmission technology. CQ-EMWD electromagnetic measurement while drilling system is developed , which is tested in 21 wells for gas drilling, underbalanced drilling, water base drilling fluid and oil base drilling fluid. The vertical depth of measurement by using this system reaches 4326 meters, solving the MWD technological bottlenecks for gas drilling and underbalanced drilling of directional wells and horizontal wells as well as complicated well status. It provides good technological support for improvement of drilling rate and drilling efficiency and reduction of MWD cost.