海底天然气渗漏地震探测方法的研究进展

海底天然气渗漏可以指示沉积层中的烃类聚集带，渗漏出的大量气体（主要是甲烷）还可能影响全球的气候变化。此外，与海底渗漏相关的浅层气改变了海底沉积物的土工性质，可能对海底工程构成威胁。因此对海底天然气渗漏进行研究意义重大。在海底渗漏探测方面，地震是一种有效的方法，它不仅能反映深部构造，为海底渗漏提供气体来源和运移通道信息；而且还可以直接用来寻找渗漏相关特征，为海底观测和取样提供依据。在地震剖面上，与海底天然气渗漏相关的浅层气表现为声混浊、声空白、亮点、多次波、速度下拉、气烟囱等特征，泥火山、泥底辟表现为隆起的地震透明带，而麻坑则表现为“V”字形截面和半透明状地震混浊。

RESEARCH PROGRESS ON SEISMIC DETECTION METHODS OF NATURAL GAS SEEPAGE ON THE SEABED

Marine Gas seepage may indicate the accumulation of hydrocarbon in sediments, and a large amount of venting gas (mainly methane) may result in the global climate change. Additionally, the seepage-related shallow gas accumulation, can significantly alter the geotechnical properties and behavior of seafloor sediments and may threaten marine engineering. So it is essential to study on the natural gas seepage in marine environment. Seismic data are very useful for the detection of marine seepage. Seismic data not only can image the deep structure and provide the conduit and gas source information for seepage, but also can be used to find gas-related features directly and guide on marine observation and sampling. On seismic profiles, seepage-related shallow gas is characterized by acoustic turbidity, acoustic wipeout, bright spots, multiples, velocity-pull down and gas chimney while mud volcanoes/diapirs are characterized by domed seismic transparent zones and pockmarks are characterized by V-shaped section and semi-transparent seismic turbidity.