水平井煤岩界面方位电磁波测井仪器探测性能

煤岩界面的预先、精准识别是实现智能化开采，提高开采效率和降低成本的关键技术之一，方位电磁波测井已在石油测井岩性界面识别中获得较好效果，但对煤岩界面识别情况的研究较少。为了研究方位电磁波在煤田测井环境中的适用性和探测性能，使用一维广义反射系数法计算磁场分量，并使用快速Hankel变换加快积分计算速度，模拟线圈系组合方式、频率、源距、线圈系半径、电阻率对比度、发射电流和电阻率各向异性对煤田方位电磁波测井响应的影响。结果表明:方位电磁波测井仪器能够分辨煤岩界面，对煤岩界面识别具有较大的应用潜力。线圈系半径和发射电流主要影响仪器响应信号的大小；在一定电阻率对比度范围内，幅度比和相位差在界面附近的幅值随电阻率对比度增大而增大，高阻地层电阻率各向异性对幅度比和相位差影响较小；仪器发射频率、源距、电阻率对比度同时影响方位信号最大探边深度。 

Detection performance of the azimuthal electromagnetic wave logging instrument at coal-rock interface in horizontal wells

The advance and accurate identification of coal-rock interfaces is one of the key technologies to realize intelligent mining, improve mining efficiency and reduce cost. Azimuthal electromagnetic wave logging has achieved good results in lithologic interface identification of petroleum logging, but the identification of coal-rock interface is seldom studied. For the purpose of studying the applicability and detection performance of azimuthal electromagnetic wave in the coalfield logging environment, the one-dimensional generalized reflection coefficient method is used to calculate the magnetic field component, and the fast Hankel transform is used to accelerate the integral calculation speed. What is more, the effects of coil system combination mode, frequency, source distance, radius of coil system, resistivity contrast, emission current and resistivity anisotropy on azimuth electromagnetic logging response in the coal field are simulated. The results show that the azimuthal electromagnetic wave logging instrument can distinguish the coal-rock interface and has a great application potential in coal-rock interface recognition. The radius of the coil system and the emission current mainly affect the size of the instrument response signal. In a certain range of resistivity contrast, the amplitude ratio and phase difference near the interface increase with the increase of resistivity contrast, and the resistivity anisotropy has little effect on the amplitude ratio and phase difference in high resistivity formation. The transmitting frequency, source distance and resistivity contrast of the instrument simultaneously affect the maximum edge depth of the azimuth signal.