冷泉气体渗漏过程海洋多电极电阻率法探测效果模拟分析

为分析评价一种新型海洋多电极电阻率法对海底沉积物中冷泉气体渗漏过程的探测能力，根据前人理论研究，结合具体实例构建沉积物中快速及慢速冷泉气体汇聚、渗漏、喷发阶段地电模型，模拟采用海洋多电极电阻率法进行探测，利用数值计算方法得到理论剖面图像，并和室内实验实测剖面图像进行对比分析。研究结果表明，在快速冷泉探测剖面图像中，含气层和渗漏通道会因冷泉气体扩散状态不同表现为不同的电阻率异常特征，但易于识别。在慢速冷泉探测剖面图像中，浅层沉积物中气体富集区呈明显的高阻异常区，随着气体渗漏异常区逐步消失。两种喷发过程形成的微地貌特征也可在探测图像中得到反映。海洋多电极电阻率法是一种可以图化描述沉积物中含气层、渗漏通道及气液界面空间分布位置的有效方法。

Detecting cold spring gas leakage in seabed sediment with marine multi-electrode resistivity method: numerical simulation and experiment

Ability of marine multi-electrode resisitivity method to detect the process of cold spring gas leakage in seabed sediment would been analysed and evaluated in this paper. In order to meet this object, on the base of predecessors'' research results and some concrete examples, the geoelectric models of sediments were built, then theoretical electrical resisitivity sections were calculated while marine multi-electrode resisitivity method was used to detect the gathering, leaking and erupting of fast or slow cold spring gas in seabed sediment. Compare the numerical simulation resisitivity images and experimental ones, some results have been generalized. In the detected section images of rapid cold spring. Gas bearing layer and leakage passages in different phases of leakage performanced for different anomaly resistivity image characteristics, but they were easy to identify. In the detected section images of slow cold spring, gas enrichment region in shallow sediment showed obvious high resistivity anomaly. As the gas leaked, abnormal area gradually disappeared. Two types of landforms formed by gas eruption process could also be reflected in the detected images. Marine multi-electrode resisitivity method was proved to be an effective method which could describe the gas bearing layer, leakage passage and spatial distribution of gas and liquid interface position with measured anomaly images.