分频迭代宽频反演方法在储层预测中的应用

Application of iterative frequency-divided broadband inversion method in reservoir prediction

鄂尔多斯盆地A区块目的层为致密砂岩储层,具有低孔、低渗、非均质性强且厚度薄等特点.常规资料无法分辨薄储层,为满足研究需求,研究区通过提高分辨率处理,获取了宽频地震资料.如何应用宽频资料预测含气有利区成为该区天然气开发面临的主要难题之一.在岩石物理分析的基础上,探索"两步法"分频迭代宽频反演含气性预测方法,首先应用分频反演方法预测泥质含量,在此基础上充分利用地震的高频信息,探索分频迭代约束稀疏脉冲反演方法预测纵波阻抗.将以上结果相结合,预测出A区块本溪组的致密砂岩储层含气有利区.实际应用结果表明,该方法能够有效地预测含气有利区,在一定程度上减少了多解性.

The target formation of block A in Ordos Basin is tight sandstone reservoir, which is characterized by low porosity, low permeability, strong heterogeneity and thin thickness. Conventional data can’t distinguish thin reservoir. In order to meet the research needs, the research area obtained broadband seismic data by improving seismic resolution. How to use broadband data to predict the favorable gas bearing area has become one of the main problems in the development of natural gas in this area. On the basis of rock physics analysis, the "two-step" iterative frequency-divided broadband inversion gas bearing prediction method is explored. Firstly, the frequency-divided inversion method is applied to predict the shale content. On this basis, the high-frequency information of the seismic data is fully utilized in the use of iterative frequency-divided constrained sparse pulse inversion method to predict the P-impedance. Combining the above results, the favorable gas bearing area of tight sandstone reservoir of Benxi Formation in block A is predicted. The practical application results show that this method can effectively predict the favorable gas bearing area and reduce the results’ multi-solution to a certain extent.