A PRELIMINARY STUDY OF GAS HYDRATES IN DONGSHA REG...

A PRELIMINARY STUDY OF GAS HYDRATES IN DONGSHA REGION NORTH OF SOUTH CHINA SEA

SONG Haibin1，2　GENG Jianhua2　WONG How-Kin3　ZHANG Wensheng4　FANG Yinxia5　HAO Tianyao1　JIANG Weiwei1

（1.Institute of Geology and Geophysics，CAS，Beijing，100029，China；2.Key Lab of Marine Geology，Tongji University，Shanghai 200092，China；3.Institute of Biogeochemistry and Marine Chemistry，Hamburg University，Hamburg D-20146，Germany；4.Institute of Computational Mathematics and Scientific/Engineering Computing，CAS，Beijing 100080，China；5.Key Lab of Submarine Geosciences，SOA，Hangzhou 310012，China）

Abstract：Seismic，sonic logging and geothermal data are analyzed for distribution characteristics of gas hydrates in Dongsha region north of the South China Sea.Bottom simulating reflectors（BSRs）and amplitude blanking zone are discovered in seismic profiles.And high-velocity interval and velocity reverse are distinguished by sonic logging.The BSR depth is compared with thickness of gas hydrates stability zone from geothermal gradient data.The BSR at ODP site 1144and 1148occur at 654and 475meters below sea floor respectively.The top of the amplitude blanking zone may be related with gas hydrates-bearing strata in a region adjacent to ODP site 1144，at about 450meters below the sea floor.(https://www.daowen.com)

Key words：Gas hydrates North of South China Sea Bottom-simulating reflectors Amplitude blanking zone　Sonic logging　Temperature-pressure condition

Originally Published in：Chinese Journal of Geophysics，2001，44（5）：684～691