似海底反射层BSR的地震精细特征及控制因素研究-----------------------.docx

Research detailed seismic features of the bottom simulating reflection (BSR) and controlling factors Abstract Natural gas hydrates are regarded as a potential clean energy resource, the base of which is marked by a bottom simulating reflection (BSR) on seismic profiles. Normally BSR is thought to the seismic indicator of gas hydrates，which has been confirmed by drilling in marine sediments. The interpretation of the high resolution 3D seismic data from offshore Mauritania reveals detailed seismic features of the bottom simulating reflection (BSR) and the controlling factors the BSR features are analyzed. The BSR is approximately parallel to the seafloor, characterized by high reflection amplitude and negative polarity. Research shows temperature and pressure conditions control the distribution of BSR, thus BSR is also characterized by crosscutting stratigraphy； high thermal conductivity or advective heat transport being concomitant of diaper may cause the up‐domed shape of the BSR; Dislocation effects of faults and landslides may cause BSR interruption or Discontinuous; cooling effect of a canyon on surrounding sediments, causing downward shift of the BSR. Temperature, pressure, salinity of pore water and gas composition jointly affect the formation of gas hydrates, and control the distribution of BSR. Thus, in the evolution of geological such as sedimentation, erosion, sea-level change, tectonics and seafloor topography, the change of temperature and pressure conditions lead to the vertical depth of the BSR change . Keywords：gas hydrates；BSR；seismic features；controlling factors Interpretation of the high resolution 3D seismic data from offshore Mauritania reveals detailed seismic features of the bottom simulating reflection (BSR) and underlying free gas zones (FGZs). The blanking zone above the BSR is interpreted to be caused by hydrate-bearing strata, and the abnormally high amplitude zone below the BSR represents a free gas zone (FGZ) sealed by hydrates. BSR is