| 天然气水合物开采过程甲烷气泄漏海床基高密度电阻率法监测效果模拟与分析 |
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| 引用本文： | 吴景鑫,郭秀军,贾永刚,孙翔,李宁.天然气水合物开采过程甲烷气泄漏海床基高密度电阻率法监测效果模拟与分析[J].吉林大学学报(地球科学版),2018,48(6):1854-1864. |
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| 作者姓名： | 吴景鑫 郭秀军 贾永刚 孙翔 李宁 |
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| 作者单位： | 1. 中国海洋大学环境科学与工程学院, 山东 青岛 266100;2. 山东省海洋环境地质工程重点实验室, 山东 青岛 266100;3. 海洋环境与生态教育部重点实验室, 山东 青岛 266100 |
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| 基金项目： | 国家重点研发项目（2017YFC0307701）；国家自然科学基金项目（41772307，41427803） |
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| 摘 要： | 为实现天然气水合物开采过程沉积物内甲烷气泄漏过程有效监测，设计了一种海床基原位电学监测方法。为界定该方法对不同模式泄露甲烷气的探测能力，以南海神狐海域天然气水合物试采区为研究区，构建相应地质及电阻率模型，模拟利用设计电学系统对其进行监测，计算得到不同采集参数的电阻率剖面，并对其进行对比分析。研究结果表明：海水层会在探测剖面上某深度区间内形成层状低阻异常带，对该深度区间有效电信号形成压制。将该异常带顶界深度定义为系统有效探测深度后，发现该深度受电极距直接影响，10 m极距偶极装置有效探测深度约为50 m。电学探测剖面对有效探测深度内分布的层状和团状甲烷气聚集区、慢速甲烷气泄露区、沿断层泄露的甲烷气区具有良好反映能力，数据处理得到的相对电阻率剖面与电学探测剖面相比能更好地反映甲烷气聚集区边界。该监测方法能够实时监测含气区空间变化。
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| 关 键 词： | 天然气水合物 甲烷气泄漏 电阻率成像法 探测剖面异常特征 |
| 收稿时间： | 2018-09-07 |
Numerical Evaluation of Electrical Resistance Tomography Monitoring of Sea Bed Basement Effect on Methane Leaks During Hydrate Production |
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| Wu Jingxin,Guo Xiujun,Jia Yonggang,Sun Xiang,Li Ning.Numerical Evaluation of Electrical Resistance Tomography Monitoring of Sea Bed Basement Effect on Methane Leaks During Hydrate Production[J].Journal of Jilin Unviersity:Earth Science Edition,2018,48(6):1854-1864. |
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| Authors: | Wu Jingxin Guo Xiujun Jia Yonggang Sun Xiang Li Ning |
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| Institution: | 1. College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, Shandong, China;2. Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering(Ocean University of China), Qingdao 266100, Shandong, China;3. Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, Shandong, China |
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| Abstract: | In order to effectively detect methane leakage of a sedimentary layer, we designed an in situ electricity monitoring system used in sea floor. The Shenhu gas hydrate production area in South China Sea was selected as the target area, and the corresponding geological models and resistivity models were established to evaluate the detection the capability of the system for methane leakage. The resistivity profiles with different acquisition parameters were calculated and analyzed by simulating and monitoring them with the designed electrical system. The simulation results indicate that the seawater forms a low-resistance stripe concomitant anomaly in a depth range of the detection profile, which suppress electrical signals in corresponding to its position. The top position of the concomitant anomaly can be defined as the effective monitoring depth. The effective monitoring depth is directly affected by the electrode distance, and the effective monitoring depth of the 10 m dipole-dipole array is about 50 m. Within the effective monitoring depth, the detection profile has a good reflection in a layered, agglomerate methane gathering area and a slow methane leaking area. The relative resistivity profiles obtained from the data processing can better reflect the boundaries of methane accumulation zones than electrical profiles. This in situ electricity monitoring system can effectively monitor the spatial variation of a methane leakage area in real time. |
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| Keywords: | gas hydrate methane leakage electrical resistivity tomography abnormal characteristics of detection profile |
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