青海木里地区陆域天然气水合物地震波阻抗特征研究

The application of constrained sparse spike impedance inversion to seismic exploration of land gas hydrate

天然气水合物主要分布在海底以下和永久冻土带。海域天然气水合物储层有比较明显的高波阻抗异常特征,但是针对陆域天然气水合物波阻抗特征的研究较少。文中针对青藏高原青海木里地区的陆域天然气水合物储层,结合DK-9井资料对经过DK-9井的L1测线二维反射地震数据进行了井约束的稀疏脉冲波阻抗反演,并分析了DK-9井中四层赋存天然气水合物的储层在波阻抗剖面上的特征,结果显示该地区陆域天然气水合物储层波阻抗特征较围岩差异性较小,无法单独通过波阻抗特征进行识别,需结合其它资料综合考虑进行识别。

Natural gas hydrates are mainly distributed below the seabed and in the permafrost zones.There are obvious characteristics for the impedance of the sea gas hydrate. Nevertheless, very insufficient research has been focused on the impedance characteristics of the land gas hydrate.In this paper, the research aimed at the land gas hydrate in Mull area of the Tibetan Plateau.The authors used the con- strained sparse-spike method to invert the impedance with 2D reflected seismic profile which crossed the DK-9 well.The authors ana- lyzed the features of the impedance profile of the four layers that contain gas hydrate.The results show that the impedance of land gas hydrate reservoir is on the whole the same as things of the surroundings.There are a lot of difficulties in detecting the land gas hydrate with wave impedance individually, and hence the reservoir should be detected in combination with other geological and geophysical data.