基于岩石物理模型的页岩孔隙结构反演及横波速度预测

发布时间：2018-10-13 11:28

【摘要】：准确预测储层的等效孔隙纵横比对页岩储层岩石物理建模及横波速度预测具有重要意义。为分析页岩储层孔隙纵横比及预测横波速度,提出了基于岩石物理模型的页岩孔隙纵横比反演及横波速度预测方法。本文首先通过岩石物理模型建立岩石的纵、横波速度与孔隙纵横比、孔隙度和矿物组分等参数之间的定量关系,寻找最佳孔隙纵横比;然后通过使理论预测与实际测量的纵波速度之间误差达到最小的方式反演孔隙纵横比,并以此为约束预测横波速度。实际测井数据反演结果表明,龙马溪组页岩地层的孔隙纵横比稳定,而围岩的孔隙纵横比变化范围较大;说明与围岩相比,页岩的孔隙结构更为稳定。同时,预测得到的页岩横波速度与实测横波速度的误差较小,另外对于缺少矿物组分资料的页岩层段,用平均矿物组分预测得到的横波速度误差仍较小;说明与矿物组分相比,龙马溪组页岩的纵、横波速度对孔隙纵横比参数更敏感。综上所述,利用该方法可预测到较为准确的等效孔隙纵横比和横波速度。
[Abstract]:It is of great significance to accurately predict the equivalent porosity aspect ratio of shale reservoir rock physical modeling and S-wave velocity prediction. In order to analyze the ratio of porosity to shear and predict shear wave velocity in shale reservoir, a method of inversion and prediction of shear wave velocity based on rock physical model is proposed. In this paper, the quantitative relationship between the longitudinal and shear wave velocities of rocks and the parameters such as the ratio of vertical to transverse porosity, porosity and mineral composition is first established by means of the rock physical model, and the optimum ratio of vertical and horizontal porosity is found. Then the porosity ratio is inversed by minimizing the error between the theoretical prediction and the measured longitudinal wave velocity, and the shear wave velocity is predicted as a constraint. The inversion results of actual logging data show that the pore aspect ratio of the Longmaxi formation shale formation is stable, while that of the surrounding rock is larger, indicating that the pore structure of the shale is more stable than that of the surrounding rock. At the same time, the error between the predicted shale shear wave velocity and the measured shear wave velocity is relatively small. In addition, the prediction error of the average mineral component is still relatively small for the shale formation which lacks the mineral component data, which shows that compared with the mineral component, the predicted shale-wave velocity error is smaller than that of the measured shear wave velocity. The longitudinal and shear wave velocities of the Longmaxi formation shale are more sensitive to the porosity parameters. In conclusion, the method can be used to predict the equivalent porosity ratio and shear wave velocity.
【作者单位】：吉林大学地球探测科学与技术学院;中国石油化工股份有限公司石油勘探开发研究院;
【基金】：国家自然科学基金重点项目(41430322);国家自然科学基金青年科学基金项目(41404090)~~
【分类号】：P631.4;P618.13

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