摘要
海洋可控源电磁探测(MCSEM)是勘查天然气水合物资源的有效方法之一.海洋可控源电磁发射系统是实现MCSEM的重要硬件组成部分.本文以天然气水合物在海底的一维地电模型为例,研究电偶源发射频率、发射偶极侧向漂移、源偶极矩大小对电场响应的影响,进而指导发射系统研制.该系统包括:甲板升压控制单元,可将船载大功率电能升为高压并通过万米光电复合缆输送至海底的发射机;水下变压器,可将深拖缆中的大功率高压转换为低压;拖曳式大功率电磁发射机,其内部的控制电路硬件和嵌入式驱动软件可将水下变压器输出的电能逆变为大功率矩形脉冲,并通过发射偶极将脉冲发送至海水介质中;借助水动力学设计的发射机拖体,用于装载发射系统水下部件和保持拖曳过程中的平衡与稳定;甲板端上位机监控单元,利用万米光电复合缆中的光纤实现船上计算机与海底发射机的远程数据通信.2012年5月和2013年5月海洋试验的结果均表明,所研制的发射系统可作为天然气水合物资源勘探的有效激励场源.
Marine Controlled Source Electromagnetic （MCSEM） is one of the effective exploration methods in exploration of natural gas hydrate resources. The launch system is an important part of the MCSEM hardware. In this work, with the seafloor 1D geo-electric model of the gas hydrate as an example, we study the effects of factors on responses of the electric field, including electric dipole source emission frequency, emission dipole lateral drift and source dipole moment value, which provide guidance for launch system design. The self-developed equipment includes the following components.- A deck boost control unit, which transfers ship-borne high-power electrical energy through a ten-thousand-meter optical-electric composite cable transported to the submarine transmitter; underwater step-down transformer and rectifier unit, that can convert the high-power AC to high＋current DC; the transmitter control circuit hardware and embedded software, that invert underwater transformer output power to high-power rectangular pulse; relying on the emission dipole of the neutral buoyancy, the high-power inverter square waves are sent to the seawater; with the help of the transmitter dynamics design of underwater towed body, used for loading transmitting system of underwater parts and maintain the balance and stability; using the Optical Modem and the fiber in ten-thousand-meter optical-electric composite cable, and remote communication that can be realized between board computer and the submarine transmitter. Marine tests in May 2012 and May 2013 show that the launch system can be used as excitation field source in marine controlled source electromagnetic for exploration of natural gas hydrate resources.
出处
《地球物理学报》
SCIE
EI
CSCD
北大核心
2013年第11期3708-3717,共10页
Chinese Journal of Geophysics
基金
国家高技术研究发展计划(863计划)项目课题(2006AA09A201,2009AA09A201)
中央高校基本科研业务费专项资金(2652011271)联合资助
