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| A model-based study of the filtering effects of thin-interbedded reservoirs on seismic reflection waves |
LUO Jing( ), SUN Cheng-Yu() |
| School of Geosciences,China University of Petroleum (East China),Qingdao 266580,China |
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Abstract The exploitation of thin-bedded and thin-interbedded hydrocarbon reservoirs has garnered increasing attention.However,seismic data of thin-bedded reservoirs exhibit low resolution,and conventional convolution models fail to simulate the complex wave field propagation phenomena in thin-bedded reservoirs,complicating the seismic prediction of such reservoirs.Hence,based on the transfer matrix method for layered media,this study developed a normal-incidence reflectance method.Using the new method,it conducted forward modeling on several typical thin-interbedded reservoir models.Then,the forward modeling results were analyzed through frequency spectrum analysis to explore the filtering effects of thin-interbedded reservoirs on seismic reflection waves.Compared to the transfer matrix method for layered media,the normal-incidence reflectance method is more applicable to the investigation of thin-interbedded reservoirs under longitudinal wave incidence,significantly enhancing the forward modeling efficiency.Moreover,studying the reflection filtering effects of thin-interbedded reservoirs in the frequency domain somewhat eliminates the shortcomings of insufficient resolution in the time domain.The frequency spectrum analysis of thin-interbedded reservoir models shows that the normal-incidence reflectance method can effectively preserve the interbed information of thin-interbedded reservoirs.As revealed by the frequency spectrum analysis of the forward modeling results based on this method,the changes in the amplitudes and notch points of frequency spectrum curves can reflect the changes in the number of interbeds and sandstone-mudstone ratios in thin-interbedded reservoirs.This finding is critical for determining the spatial distributions and properties of thin-bedded reservoirs in the fine-scale exploration of oilfields.
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Received: 01 November 2023
Published: 19 September 2024
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Layered media model
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Rhythmic thin interlayer models
the thickness of thin interlayer is:a—21×1 m;b—21×2 m;c—42×1 m;d—42×2 m
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Incremental thin interlayer models
the thickness of thin interlayer is:a—21×1 m;b—21×2 m;c—42×1 m;d—42×2 m
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Decreasing thin interlayer models
the thickness of thin interlayer is:a—21×1 m;b—21×2 m;c—42×1 m;d—42×2 m
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Sandstone cumulative thickness invariant thin interlayer models
the stratification of sandstone is:a—1×18 m;b—2×9 m;c—3×6 m;d—6×3 m;e—9×2 m;f—18×1 m
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Total thickness invariant thin interlayer models
the stratification of thin interlayer is:a—1×15 m;b—3×5 m;c—5×3 m;d—15×1 m
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Sand to mud ratio in a single set of sand and mud layers variant thin interlayer models
the sand to mud ratio of a single set of sand and mud layer is:a—0.3;b—1;c—3;d—9
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Forward shot record of stratigraphic structure variant thin interlayer models
a—forward shot record of rhythmic thin interlayer models;b—forward shot record of incremental thin interlayer models;c—forward shot record of decreasing thin interlayer models;the thickness of the thin interlayer from left to right is:21×1 m;21×2 m;42×1 m;42×2 m
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Forward shot record of sand to mud ratio variant thin interlayer models
a—forward shot record of sandstone cumulative thickness invariant thin interlayer models,the stratification of sandstone from left to right is:1×18 m,2×9 m,3×6 m,6×3 m,9×2 m,18×1 m;b—forward shot record of total thickness invariant thin interlayer models,the stratification of thin interlayer from left to right is:1×15 m,3×5 m,5×3 m,15×1 m;c—forward shot record of sand to mud ratio in a single set of sand and mud layers variant thin interlayer models,the sand to mud ratio of a single set of sand and mud layer from left to right is:0.3,1,3,9
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Reflected waveform of stratigraphic structure variant thin interlayer models
a—rhythmic thin interlayer models;b—incremental thin interlayer models;c—decreasing thin interlayer models
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Reflected waveform of sand to mud ratio variant thin interlayer models
a—sandstone cumulative thickness invariant thin interlayer models;b—total thickness invariant thin interlayer models;c—sand to mud ratio in a single set of sand and mud layers variant thin interlayer models
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Spectrogram of stratigraphic structure variant thin interlayer models
a—rhythmic thin interlayer models;b—incremental thin interlayer models;c—decreasing thin interlayer models
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Spectrogram of sand to mud ratio variant thin interlayer models
a—sandstone cumulative thickness invariant thin interlayer models;b—total thickness invariant thin interlayer models;c—sand to mud ratio in a single set of sand and mud layers variant thin interlayer models
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