Beach-bar reservoirs in the Sanhebei area of the North Jiangsu Basin are complex for thickness-varying caprocks shielding the underlying lithofacies-varying reservoir with weak signals.Fine characterization of such reservoirs is more challenging than conventional beach-bar reservoirs.In this paper,well-seismic calibration was conducted for the area of interest to clarify the features of three sand zones in the second member of Funing Formation(Fu-2 Member).On this basis,an approach of frequency enhancement by compressed sensing+strong reflection deshielding by multi-trace matching pursuit+90° phase shift was proposed for sandstone prediction.The results of model tests and field data application are obtained in four aspects.First,the composite reflections from thickness-varying caprocks could be separa-ted effectively using frequency enhancement through sparse reflectivity inversion based on compressed sensing.Second,using the amplitude-modulated multi-trace matching pursuit method,reflection energy from caprocks could be partially mitigated under a controlled manner,so that the reflection events of the sand zone in the reservoir are consistent with the thickness of the sand zone.Third,favorable sands can be visually interpreted after 90° phase shift.Fourth,the distribution of beach-bars in the study area can be well identified through combining dominant seismic attributes with T0 structure map and seismic facies.The proposed characterization method is theoretically and practically significant for complex beach-bar reservoirs.
维普
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