海底瞬变电磁探测技术的装置参数研究及实验

可控源时间域电磁法应用在海底探测,需要确定装置参数,通过实验和理论计算确定了发射频率的最大值;分析了发射线圈的电性对发射电流后沿的影响,确定了作为发射线圈的导线的时间常数应尽量小;对接收线圈的参数及过渡过程进行了理论分析和室内模型实验,理论计算了接收线圈电路模型在发射电流斜阶跃下降和关断后在欠阻尼、临界阻尼和过阻尼状态的一次感应电动势解的情况,确定了采用并联匹配电阻消除振荡的方法,并依据所分析的装置参数设计实施了海上实验,探测出海底低阻体的准确位置.

Equipment parameters and experiment of sea-floor transient electromagnetic method

For a sea-floor transient electromagnetic exploration system, its maximum transmitting frequency may be chosen as 200 Hz by supposing the sea-floor as horizontal thin conductive plates. By analyzing the parameters of the transmitting loop and the effect of late-time of transmitting current, a small time constant of wire of transmitting loop is determined. By calculating the response curve of the receiver loop circuit in the cases of different damp coefficients, a parallel matched resistance is employed to remove the vibrating phenomenon. Based on the analysis, the field experiment on the sea is accomplished and the body of low resistivity is detected.