辽西金羊盆地大地电磁测深参考道处理效果研究

摘要

Magnetotellurics (MT) is a passive exploration technique that utilizes a broad spectrum of naturally occurring geomagnetic variations as a power source for electromagnetic induction in the Earth.It is widely used in the hydrocarbon exploration as a supplement to seismic exploration because of its portability,low cost and detective depth.The Jinyang Basin in Western Liaoning,with great resources potential,suffers electromagnetic interference of near-field sources,which cannot be ignored.The noise caused by electrical pulse may have significant impact on electric field in limited areas.The noise from charge-discharge would greatly influence the magnetic field in broad areas.Therefore it is important to adopt noise suppression method in MT.The magnetic reference method involves deploying additional sensors at a site remote from the local measurement site.By measuring selected electromagnetic components at both local and remote sites,bias effects arising from the presence of noise that is uncorrelated between sites can be removed.It can maximize the signal-to-noise ratio and improve the quality of magnetotelluric data.The quality of MT data can also be improved with the increasing of acquisition time.%大地电磁测深法是一种利用天然交变的电磁场进行深部地质构造研究的频率域电磁测深方法,因其装备轻便、成本低、勘探深度大等特点,作为地震勘探的有利补充,被广泛应用于油气资源勘查领域.金羊盆地具有良好的油气资源潜力,但因其处于人文电磁干扰严重地区,近场源电磁干扰不可忽视,脉冲噪声虽影响范围小但其对电场信号干扰较大,充放电噪声对磁场干扰较大,且影响区域较广,有效压制噪声对天然电磁场信号的干扰具有重要意义.参考点选择适当,参考道数据处理技术可以有效压制非相关噪声,提高信噪比,改善数据质量.适当增加大地电磁测深数据的采集时长,对提高单点数据处理质量和参考道数据处理质量均有明显作用.