基于纵横波弹性阻抗联合反演的储层流体检测方法

Reservoir fluid detection method based on joint PP- and PS-wave elastic impedance inversion

冷雪梅 杜启振 孟宪军2

中国石油大学（华东）地球科学与技术学院，山东 青岛 266580 中国石化胜利油田分公司物探研究院，山东 东营 257022

School of Geosciences, China University of Petroleum, Qingdao 266580, China Geophysical Research Institute, Shengli Oilfield Company, SINOPEC, Dongying 257022, China

叠前弹性阻抗反演是储层含油气检测的重要方法，仅用叠后纵波资料反演存在反演过程不稳定、精度低等问题。为此，文中提出了基于叠前纵横波弹性阻抗联合反演的储层流体检测方法。首先，通过敏感性对比分析选取了流体因子F?籽，该流体因子敏感性与Russell流体因子接近，避免了计算纵横波速度比产生的误差；其次，借鉴Connolly弹性阻抗方法，推导了基于流体因子和岩性指示因子E?籽的纵波和转换横波弹性阻抗方程；最后，通过弹性阻抗反演直接提取F?籽及E?籽进行流体检测。模型测试验证了该方法具有较好的稳定性，提高了反演精度。实际资料测试表明，该方法得到的F?籽和E?籽可以较好地区分岩性并识别流体，从而有效地进行储层流体检测。

Pre-stack elastic impedance inversion is an important method for oil and gas reservoir detection. Inversion only using the three parameters of post-stack PP-wave data can lead to instability and low accuracy. In this paper, a fluid detection method based on joint inversion of PP- and PS-wave elastic impedance is proposed. First, fluid factor Fρ is selected through sensitivity comparison and analysis. Selection of this fluid factor can avoid the error from calculating the ratio of P-wave velocity and S-wave velocity, while it has a comparable sensitivity with Russell fluid factor. Then, elastic impedance equations of PP-wave and PS-wave based on fluid factor Fρ and lithology indicator Eρ are derived with reference to the Connolly elastic impedance principle. Finally, fluid factor Fρ and lithology indicator Eρ can be directly extracted for fluid detection with the elastic impedance inversion method. Model test shows that the proposed method presents good stability and can improve the accuracy of inversion results. Tests on real data also indicate that fluid factor and lithologic indicator obtained from this inversion method perform better in identifying fluid and distinguishing lithology, which contributes to effective reservoir fluid detection.

10.6056/dkyqt201903010