基于MIP-CPT技术的海底浅层气探测方法——以东海舟山海域为例

A new method for detecting submarine shallow gas based on MIP-CPT technology:a case study of Zhoushan sea area,East China Sea

国际上MIP-CPT技术在陆域环境污染监测领域得到了较成功的应用。为了准确识别海底浅层气,避免其对海洋开发的影响,采用MIP-CPT技术,辅以其他多种地球物理探测方法,在东海舟山海域进行了海上试验。基于得到的MIP数据识别了测试海域海底面以下30 m内的游离气和溶解甲烷,将典型孔位的FID信号与同位置的浅地层剖面进行对比,基本符合地球物理勘察的结果;结合同时得到的多项CPTU数据对MIP数据进一步分析发现测试海域的浅层气主要来源于较深部地层,并得到了多道地震勘探数据的旁证。研究表明相对于传统浅层气探测手段,MIP-CPT技术具有快捷性、直观性和多数据的优势,这种技术很适合研究海底浅层气的成因机制。

Membrane Interface Probe and Cone Penetration Technology(MIP-CPT)have been successfully applied in the field of environmental pollution monitoring around the world.To accurately identify submarine shallow gas and avoid its interference in ocean development,MIP-CPT technology was adopted together with multiple geophysical detection methods for experiments in Zhoushan sea area,East China Sea.Based on available MIP data,the free gas and soluble methane within30 meters below the seafloor were identified;a comparison was performed on FID signals of typical hole sites and sub-bottom profiles at the same locations,and the results are basically consistent with those of geophysical survey.In combination with the obtained multiple CPTU data,a further analysis was conducted on MIP data to reveal that the shallow gas in this sea area was sourced from deeper strata,which was also verified by multi-channel seismic prospecting data.The research indicates that compared with conventional shallow gas detection methods,MIPCPT technology has the advantages of rapidity,visualization and multi-data,which was suitable for studying the genetic mechanism of submarine shallow gas.