Abstract:
Petrological analysis has shown that the low-permeability genesis of Oilfield B mainly includes primary sedimentation, strong compaction, and strong cementation in late diagenesis.However, sedimentary microfacies primarily control the relatively high-permeability dessert layers developed locally in low-permeability reservoirs.In this oilfield, the petrophysical characteristics of the local dessert layers are slightly different from those of tight reservoirs.Therefore, high permeability dessert layers are difficult to distinguish using conventional geophysical methods.Based on the different geneses of sand bodies, this study first summarized the vertical superposition mode of dessert layers in a tight reservoir, established representative models with varying thicknesses of reservoir, dessert thicknesses, dessert locations, and dessert heterogeneity changes, and conducted forward modeling.Theoretical seismic attributes that were relatively sensitive to different superimposed geological models were selected, and a multi-sensitive attribute combination chart was constructed according to the different reflection characteristics.Finally, the superposition pattern of the dessert layers in the tight reservoir was identified by matching the "multi-sensitive attribute combination" chart with the actual seismic attribute.In this way, the dessert layers of Oilfield B were predicted, and the results were in accordance with the drilling.This method improved the accuracy of dessert prediction using seismic attributes and provided a new method for evaluating and developing low-permeability tight oil.