海底宏渗漏气体走航式海洋电阻率法探测效果模拟与观测系统设计

为实现海底宏渗漏气体连续调查，提出了一种走航式海洋电阻率探测技术。根据前人原位观测资料和含气水体电阻率特征构建地电模型；采用数值模拟和室内试验方法获得不同参数电阻率映像剖面，分析确定探测剖面异常特征，评价探测效果。在此基础上进一步进行了探测系统设计和实验测试。研究结果表明，走航式海洋电法探测电缆可由2个供电电流极和8个电位测量极组成，电位极距需小于0.05 m；测量可采用偶极装置通过并行采集方式实现。气体分布区表现为高阻异常，异常模式由走航速度、排列长度和气体分布区横向宽度共同决定，可分为7种情形；探测电阻率极大值和气体喷出流速存在正相关指数关系。该技术可实现气体分布范围和喷出速率快速探测。

Simulation analysis of the detection effect of navigation marine direct current resistivity to seabed macro seepage and a system's design

To achieve continuous survey of seabed macro seepage, the application of a navigation marine direct current resistivity survey method is initiated in this paper. To guarantee the feasibility of the proposed method, geoelectric models have been built based on the existing in-situ observation and resistivity characteristics of gas-bearing water. In this case, resistivity sections imagine with different design parameters are obtained by numerical simulation and laboratory tests; the anomaly characteristics of resistivity sections are analyzed and the detection effect of the method is evaluated. And on this basis, the design of detection system design and experimental test are further carried out. The study results indicate that the cable of navigation 2D electrical imaging system could be composed of 2 current electrodes and 8 voltage electrodes, and the spacing between electrodes must be less than 0.05 m; then measurement can be achieved by means of parallel acquisition of dipole-dipole array. Gas distribution area shows obvious high-resistivity anomaly. The pattern of this anomaly can be categorized into 7 types, which were jointly determined by the factors of travel speed, the length of the arrangement and the lateral width of the gas distribution area. There is a positive exponential relation between the maximum value of resistivity can be detected and the rate of gas eruption. Conclusively, the navigation 2D electrical imaging method is an demonstrated method which could effectively detect the range of gas distribution and the rate of gas eruption in a quick manner.