福建宁德近岸海域海底浅层气分布特征及成因分析

近年来，在海岸带区域的开发利用过程中，遇到了一系列海岸带地质灾害问题，其中海底浅层气影响尤为严重，严重破坏海底沉积层结构的稳定性，已成为影响近岸海域工程建设施工安全的重要因素。为查明宁德近岸海域浅层气的分布特征及成因，通过单道地震、浅地层剖面、侧扫声呐等工作手段，在宁德近岸海域发现了多处呈层状、团块状分布的浅层气，分布深度一般为20 m以浅。在对该区浅层气分布特征、地震剖面分析的基础上，对比前人在邻区海域浅层气的成因分析，结合宁德海域地质演化以及沉积历史，基本确定宁德海域浅层气的成因为生物成因浅层气，同时讨论了浅层气对近海海洋工程施工的危害及预防措施。

Distribution characteristics and genesis analysis of submarine shallow gas in Ningde coastal area,Fujian Province

In recent years, a series of coastal geohazard problems have been exposed during the development of the coastal area, among which the impact of submarine shallow gas is particularly serious, seriously destroying the structure stability of the submarine sediment layer as an important factor affecting the construction safety of offshore engineering. In order to ascertain the distribution characteristics and geneses of shallow gas in Ningde offshore, by means of single-channel seismic, shallow stratigraphic profile, side-scan sonar and other methods, a number of shallow gas hosted in form of layers and clusters was found in the depth of 20 m underground in the area. Based on the analysis of the distribution characteristics and seismic profiles of shallow gas in this area, in comparison with previous genesis analyses of shallow gas in neighboring areas and in combination with the geological evolution and sedimentary history of Ningde sea, we basically determined that the shallow gas in Ningde sea were derived from biogenic origin, and discussed the harm of shallow gas to offshore engineering construction and its preventive measures.