Hydrocarbon generation and indicator in the western Ulleung Basin

울릉분지 서부에서의 탄화수소 생성 및 지표

  • 류병재 (한국지질자원연구원 석유해저자원연구부) ;
  • 김지훈 (한국지질자원연구원 석유해저자원연구부) ;
  • 이영주 (한국지질자원연구원 석유해저자원연구부) ;
  • ;
  • ;
  • 김일수 (한국석유공사 국내탐사팀)
  • Published : 2007.06.21

Abstract

Piston cores retrieved from the western Ulleung Basin, East Sea were analyzed to examine the potential for hydrocarbon generation and to determine the hydrocarbon indicators. 2D multi-channel reflection seismic and Chirp data were also investigated for mapping and characterizing the geophysical hydrocarbon indicators such as BSR (bottom simulating reflector), blank zone, pock-mark etc. High organic carbon contents and sedimentation rates that suggest good condition for hydrocarbon generation. High pressure and low temperature condition, and high residual hydrocarbon concentrations are favor the formation of natural gas hydrate. In the piston cores, cracks generally oriented to bedding may indicate the gas expansion. The seismic data show several BSRs that are associated with natural gas hydrates and underlying free gas. A number of vertical to sub-vertical blank zones were well identified in the seismic sections. They often show the seismic pull-up structures, probably indicating the presence of high velocity hydrates. Numerous pockmarks were also observed in the Chirp profiles. They may indicate the presence of free gas below the hydrate stability zone as well.