Various factors controlling the accumulation of natural gas hydrates (NGHs) form various enrichment and accumulation modes through organic combination. This study mainly analyzes the geological and geophysical characteristics of the NGHs occurrence in the uplifts and their slope zones within the deep-water area in the Qiongdongnan (QDN) Basin (also referred to as the study area). Furthermore, it investigates the dominant governing factors and models of NGHs migration and accumulation in the study area. The results are as follows. (1) The uplifts and their slope zones in the study area lie in the dominant pressure-relief direction of fluids in central hydrocarbon-rich sags in the area, which provide sufficient gas sources for the NGHs accumulation and enrichment through pathways such as gas chimneys and faults. (2) The top and flanks of gas chimneys below the bottom simulating reflectors (BSRs) show high-amplitude seismic reflections and pronounced transverse charging of free gas, indicating the occurrence of a large amount of gas accumulation at the heights of the uplifts. (3) Chimneys, faults, and high-porosity and high-permeability strata, which connect the gas hydrate temperature-pressure stability zones (GHSZs) with thermogenic gas and biogenic gas, form the main hydrate migration system. (4) The reservoir system in the study area comprises sedimentary interlayers consisting of mass transport deposits (MTDs) and turbidites. In addition, the reservoir system has developed fissure- and pore-filling types of hydrates in the pathways. The above well-matched controlling factors of hydrate accumulation enable the uplifts and their slope zones in the study area to become the favorable targets of NGHs exploration.

Yu-lin He;Jin-qiang Liang;Zeng-gui Kuang;Wei Deng;Jin-feng Ren;Hong-fei Lai;Miao-miao Meng;Wei Zhang

Southern Marine Science and Engineering Guangdong Laboratory,Guangzhou 511458,China;Guangzhou Marine Geological Survey,China Geological Survey,Ministry of Natural Resources,Guangzhou 510075,China;National Engineering Research Center of Gas Hydrate Exploration and Development,Guangzhou 511458,China

中国地质（英文）

[1]Yu-lin He;Jin-qiang Liang;Zeng-gui Kuang;Wei Deng;Jin-feng Ren;Hong-fei Lai;Miao-miao Meng;Wei Zhang-.Migration and accumulation characteristics of natural gas hydrates in the uplifts and their slope zones in the Qiongdongnan Basin, China)[J].中国地质（英文）,2022(02):234-250

NGHs,QDN,Chimneys,GHSZs,turbidites

Migration,accumulation,characteristics,natural,gas,hydrates,uplifts,their,slope,zones,Qiongdongnan,Basin,China,Various,factors,controlling,form,various,enrichment,modes,through,organic,combination,This,study,mainly,analyzes,geological,geophysical,occurrence,within,deep,water,area,also,referred,Furthermore,investigates,dominant,governing,models,migration,results,follows,pressure,relief,direction,fluids,central,hydrocarbon,sags,which,provide,sufficient,sources,pathways,such,chimneys,faults,top,flanks,below,bottom,simulating,reflectors,BSRs,show,high,amplitude,seismic,reflections,pronounced,transverse,charging,free,indicating,large,amount,heights,porosity,permeability,strata,connect,temperature,stability,thermogenic,biogenic,system,reservoir,comprises,sedimentary,interlayers,consisting,mass,transport,deposits,MTDs,In,addition,has,developed,fissure,pore,filling,types,above,well,matched,enable,become,favorable,targets,exploration

0.485948