Pre-stack Simultaneous Inversion of 3D Seismic Data for Velocity Attributes to Delineate Channel Sand Reservoir

Channel sand acts as stratigraphic trap for hydrocarbon accumulation in many parts of the world. Delineation of this type of reservoir is crucial as channel sand may be scarce and inaccurate location of the drilling wells could lose a huge currency. To differentiate channel sand from the host rocks, attributes such as P and S wave velocity ratio plays a vital role in the study area. The velocity ratio showed a negative relationship with the sand percentage in the formation i.e. lower the ratio higher the percentage of sand. After proper data preconditioning, simultaneous inversion of pre-stack angle gathers is performed to get P and S wave impedances and VP/VS ratio. The output ratio from the inversion follows the distribution of the channel sand which is evident from the blind wells penetrated the target reservoir. This finding on the extension of the channel sand reservoir in terms of velocity ratio can be used for quantitative interpretation of the reservoir properties which lead to reservoir management, future planning of the field, and setting location for new wells. Keywords—3D Seismic Data, Channel Sand Reservoir, Data Preconditioning, Pre-stack Inversion, VP/VS ratio.