泊松比岩性预测方法研究——以准噶尔盆地为例

Lithology prediction by Poisson's ratio—An example from Junggar Basin,NW China

为了研究具有高速泥岩段地层的岩性识别方法,利用实验室数据和全波列测井数据,建立泊松比岩性量板,再应用AVO反演技术获得泊松比数据体,进而利用泊松比值进行岩性预测。不同岩性地层的泊松比差异明显,砂岩与泥岩差别较大,钙质泥岩与砂岩的差异更大,说明采用泊松比数据进行岩性预测比采用纵波阻抗数据的效果更好。泊松比岩性量板分析表明,该方法可以很好地区分砂岩和泥岩,也能够有效地区分砂岩和高速泥岩;对于深度小于3000m的地层,应用泊松比法能够有效地进行含油气性预测。准噶尔盆地石南区块的泊松比反演结果表明,在纵波阻抗上难以分辨的高速泥岩与砂岩在泊松比剖面上区分得非常清楚,预测砂体、油层边界和实际钻探、试油资料相吻合,说明泊松比岩性预测方法可以弥补纵波阻抗反演的不足,提高储集层预测的精度,降低岩性勘探的风险。

This paper puts forward a new method of identifying lithology of high-speed mudstone layers by using Poisson＇s ratio, in which, the Poisson＇s ratio calibration template is set forth based on lab data and full-wave log data, and the Poisson＇s ratio data volume is calculated through the AVO inversion technology. The Poisson＇s ratios of sandstone and mudstone are obviously different and that difference between calcareous mudstone and sandstone is even greater, showing that the method is better in predicting lithology than P-wave impedance. The Poisson＇s ratio calibration template analysis shows that the method can effectively distinguish between sandstone and mudstone, and between sandstone and high-speed mudstone. It can effectively predict the hydrocarbon of formations within 3000m. In the Poisson＇s ratio inversion of the Junggar basin, sandstone and high-speed mudstone can be clearly identified in the Poisson＇s ratio profiles, while it is impossible in P-wave impedance. The predicted sandstone and reservoir boundary match the real drilling and production test, suggesting the method can offset the shortcomings of P-wave impedance inversion, enhance the prediction accuracy, and reduce the lithologic exploration risk.