青海木里地区天然气水合物三维地震探测

首次在中国祁连山冻土区青海木里地区实施了针对天然气水合物的三维地震探测。根据工区内冻土层厚度、地层岩性、水合物储集空间类型和赋存深度等特 点，设计了三维地震数据采集方案，制定了地震数据处理流程，获得了良好的三维地震探测结果。结果表明，工区内天然气水合物赋存层段地震响应特征与国外冻土区的天然气水合物具有明 显差异；冻土层厚度、岩性、水合物储集空间类型等因素，对该区地震资料振幅、频率、速度等影响显著；水合物层段的地震资料存在低频、中等杂乱振幅等明显的特点，这些特征为该区天然气水合物探测和识别提供了依据。

3D Seismic Detection for Natural Gas Hydrates in Muli Area,Qinghai

The 3D seismic data were firstly acquired to explore gas hydrates in permafrost area in Muli of Qinghai. According to the features of permafrost thickness, formation lithology, the pore type and hydrate-bearing depth of reservoir, the scheme of 3D seismic data acquisition and processing was designed, and a satisfied result was gained. Based on the analysis of these seismic data it is found that the structure and seismic response characteristics of the formation in this area are obviously different from aboard hydrate-bearing permafrost zones. The gas hydrate in Muli area is mainly filled in fractures of reservoirs, occasionally in the pores; in addition, the hydrate formation is also controlled by the depth and lithology of permafrost. As a result, the characteristics of seismic responses, such as amplitude, frequency and speed have some unique features. Combined with the geological data of the study area, it is revealed that the seismic responses of hydrate-bearing intervals manifest low frequency and disorderly medium oscillation amplitude. These characteristics can provide valuable proof to recognize gas hydrates in the study area.