The Shenhu submarine canyon group is the main target area for gas hydrate exploration in the northern South China Sea.This paper utilizes multi-channel seismic data from the region,along with results from gas hydrate exploration and trial production,to detail the sedimentary facies characteristics of the Shenhu canyon area.The submarine canyon sedimentary system is divided into two subfacies:canyon filling and canyon edge.The canyon filling subfacies comprises four microfacies:turbidity channel,lag deposit,laterally inclined deposit,and mass-flow transport deposit(MTD).The canyon edge subfacies includes three microfacies:natural levee deposit,turbidite fan,and MTD.Analysis of sedimentary units and BSR distribution in the Shenhu canyon group reveals that natural levee deposit and MTD microfacies are favorable for hydrate enrichment in the canyon sedimentary system since the Pliocene.Based on the position and characteristics of BSR in these facies belts,three BSR types are identified:A-type(ridge dome pattern),B-type(ridge edge straight pattern),and C-type(canyon edge gradient change pattern).Considering the geological hazard mechanism of potential submarine landslides caused by gas hydrate decomposition,C-type BSR is identified as a high-risk area for hydrate-induced collapse.This is due to its increasing apparent dip angle and thinning overlying strata.The research results provide important data and technological support for the next phase of gas hydrate pilot production,especially in evaluating and predicting environmental stability in the Shenhu area.
关键词
南海北部/神狐峡谷/天然气水合物/沉积体系/BSR/滑坡
Key words
northern South China Sea/Shenhu canyon/gas hydrate/sedimentary system/BSR/landslide
维普
万方数据