Open AccessSeismic characterization of hydrates in faulted, fine‐grained sediments of Krishna‐Godavari basin: Unified imaging
Author(s) -
Jaiswal P.,
Dewangan P.,
Ramprasad T.,
Zelt C. A.
Publication year - 2012
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011jb009024
Subject(s) - geology , coring , advection , clathrate hydrate , mineralogy , fault (geology) , structural basin , inversion (geology) , petrology , hydrate , geomorphology , seismology , drilling , materials science , chemistry , physics , organic chemistry , thermodynamics , metallurgy
A combination of diffusion and advection in fine grained sediments can create a patchy Bottom Simulating Reflector (BSR) which has little to no apparent correlation with the overlying hydrate distribution. Using 2D seismic data from faulted, clay‐rich sediments in the Krishna‐Godavari (KG) basin, we show both the hydrate distribution and the BSR structure are fault controlled. Our demonstration hinges upon a kinematically accurate P wave velocity (V P ) model which is estimated using a composite traveltime‐inversion, depth‐migration method in an iterative manner. The flexibility of the method allows simultaneous usage of traveltimes from multiple, discontinuous reflectors. The application begins with a simple V P model from time processing which is reflective of a diffusive, continuous, hydrate– and free gas–bearing system. The application converges in three iterations yielding a final V P model which is suggestive of a patchy distribution of hydrates and free gas possibly developing through a combined diffusive‐advective system. The depth image corresponding to the final V P model can be interpreted for faults that suggest ongoing tectonism. The BSR appears to be truncated at active faults zones. Both the final V P model and the corresponding depth image can be reconciled with the hydrate distribution and BSR depth at logging/coring sites located ∼250 m away from the line by projecting the sites along the strike direction of the regional faults.