Abstract

The problem of imaging the sub-surface accurately is always a challenge to the Geoscientists. This requires a proper understanding of the geology of the area/basin, objective of survey, adequate acquisition geometry to delineate the prospect and overall a smart processing of the data. In this paper, we will discuss the efficacy of time & depth migration in a 2D high resolution dataset of CBM block. The Time Migration algorithm result in events being spatially mispositioned and the results have the obvious drawback being represented by a two way travel time. The depth migration, not only provide an image in depth, but also avoid many assumptions and simplifications that causes mispositioning of events in the time domain. The reflections are positioned correctly and provide precise subsurface images with minute structural discontinuities, i.e. imaging of faults. The depth imaging techniques such as Pre stack depth migration is very much dependent on the interval velocity, which requires more accuracy in velocity model building. In this paper, a 2D high resolution data pertaining to CBM block has been taken as a case study. An integrated Pre-Stack Time & Depth Migration using model based velocity estimation and iterative refinement, reveals better sub-surface configuration and resolution of coal seams in the area.