基于高分辨率波形指示反演方法在“甜点”预测中的应用:以四川盆地焦石坝地区页岩储层为例

Inversion Method Based on High-resolution Waveform and Its Application on Predicting Sweet Spots:An Example from Shale Gas Reservoirs in Jiaoshiba Area of Sichuan Basin

针对常规叠后稀疏脉冲反演方法分辨率不足,以及传统叠后地质统计学反演方法缺乏横向地质意义的局限,应用基于高分辨率波形指示反演方法刻画了四川盆地焦石坝地区龙马溪组页岩薄储层段波阻抗剖面展布及其优质页岩储层段时间域厚度平面展布情况。通过对焦石坝地区龙马溪组页岩薄储层段波阻抗剖面展布进行"盲井"检测,与常规叠后稀疏脉冲反演方法的刻画精度相比,高分辨率波形指示反演方法计算结果的刻画精度提高了一倍。进一步应用高分辨率波形指示反演方法模拟了焦石坝地区龙马溪组页岩薄储层段有机碳含量(TOC)剖面展布,为后期页岩储层精细评价以及"甜点"预测奠定了基础。

The resolution of the conventional post-stack sparse pulse inversion method is low,and the traditional geostatistical inversion method also lacks the lateral geological significance. For these limitations,this paper proposed an inversion method based on high-resolution waveforms. This inversion method was employed to por-tray the distribution profile of wave impedance of the thin shale reservoir on Longmaxi Formation in Jiaoshiba area of Sichuan Basin,and to describe the plane distribution profile of thickness of high quality shale reservoirs in time domain. In the performance for random-well detection on the distribution profile of wave impedance in target reservoirs,the accuracy of this method had doubled comparing with the conventional post-stack sparse pulse inversion method. This inversion method was further applied to simulate the distribution profile of TOC in the target reservoir,and the results laid a foundation for the later‘sweet spots＇ evaluation and fine evaluation of shale reservoirs.