BSR meaning in oil and gas

The seismic reflector associated with the base of the hydrate stable layer in the marine subsurface. The BSR commonly imaged on seismic reflection profiles, is an acoustic impedance marker associated with the base of the clathrate blanket. Where free gas occurs beneath the clathrate layer, a strong negative impedance contrast occurs because of the pronounced velocity and density change. The BSR is usually subparallel to the sea floor. See also Clathrates