Genetic source,migration and accumulation of helium under deep thermal fluid activities:A case study of Ledong diapir area in Yinggehai Basin,South China Sea  

作　　者：FENG Ziqi HAO Fang HU Lin HU Gaowei ZHANG Yazhen LI Yangming WANG Wei LI Hao XIAO Junjie TIAN Jinqiang 

机构地区：[1]State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao 266580,China [2]School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China [3]Laboratory for Marine Mineral Resources,Qingdao Marine Science and Technology Center,Qingdao 266237,China [4]Hainan Branch of CNOOC(China)Co.,Ltd.,Haikou 570312,China

出　　处：《Petroleum Exploration and Development》2024年第3期753-766,共14页石油勘探与开发（英文版）

基　　金：Supported by the National Natural Science Foundation of China(41821002,42272163,42072167);Laoshan Laboratory Science and Technology Innovation Project(LSKJ202203403);Hainan Branch Project of CNOOC(KJZH-2021-0003-00).

摘　　要：Based on the geochemical parameters and analytical data,the heat conservation equation,mass balance law,Rayleigh fractionation model and other methods were used to quantify the in-situ yield and external flux of crust-derived helium,and the initial He concentration and thermal driving mechanism of mantle-derived helium,in the Ledong Diapir area,the Yinggehai Basin,in order to understand the genetic source,migration and accumulation mechanisms of helium under deep thermal fluid activities.The average content of mantle-derived He is only 0.0014%,the ^(3)He/^(4)He value is(0.002–2.190)×10^(−6),and the R/Ra value ranges from 0.01 to 1.52,indicating the contribution of mantle-derived He is 0.09%–19.84%,while the proportion of crust-derived helium can reach over 80%.Quantitative analysis indicates that the crust-derived helium is dominated by external input,followed by in-situ production,in the Ledong diapir area.The crust-derived helium exhibits an in-situ 4 He yield rate of(7.66–7.95)×10^(−13)cm^(3)/(a·g),an in-situ 4 He yield of(4.10–4.25)×10^(−4)cm^(3)/g,and an external 4 He influx of(5.84–9.06)×10^(−2)cm^(3)/g.These results may be related to atmospheric recharge into formation fluid and deep rock-water interactions.The ratio of initial mole volume of 3 He to enthalpy(W)is(0.004–0.018)×10^(−11) cm^(3)/J,and the heat contribution from the deep mantle(X_(M))accounts for 7.63%–36.18%,indicating that deep hot fluid activities drive the migration of mantle-derived 3 He.The primary helium migration depends on advection,while the secondary migration is controlled by hydrothermal degassing and gas-liquid separation.From deep to shallow layers,the CO_(2/3) He value rises from 1.34×10^(9)to 486×10^(9),indicating large amount of CO_(2)has escaped.Under the influence of deep thermal fluid,helium migration and accumulation mechanisms include:deep heat driven diffusion,advection release,vertical hydrothermal degassing,shallow lateral migration,accumulation in traps far from faults,partial pressure

关 键 词：deep thermal fluid HELIUM genetic source migration and accumulation mechanism Yinggehai Basin 

分 类 号：P618.13[天文地球—矿床学]