渝东南五峰—龙马溪组优质页岩储层脆性评价

Brittleness evaluation of Wufeng and Longmaxi formation highquality shale reservoir in southeast of Chongqing

在渝东南地区五峰组-龙马溪组优质页岩储层的脆性评价过程中,单纯力学参数计算的脆性指数精确性不足,针对此问题需考虑矿物含量的相对影响。在岩石力学实验基础上,首先通过脆性矿物和黏土矿物等分析计算,分别利用岩石物理参数和矿物组分求取了脆性指数,比较了二者的优缺点;进而,组合岩石物理参数和矿物组分,得到新的脆性指数求取公式;最后,对南川地区优质页岩储层段脆性进行了综合评价。评价结果表明:与实测脆性对照,新公式具有良好效果;南川地区五峰—龙马溪组一段平均脆性大于70%,横向分布稳定,具有良好的压裂条件。

In the process of evaluating the brittleness of the Wufeng Formation-Longmaxi Formation high-quality shale reservoirs in southeastern Chongqing,the accuracy of the brittleness index calculated by mechanical parameters is insufficient,and the relative influence of mineral content needs to be considered.Through the analysis and calculation of brittle minerals and clay minerals in reservoir,the brittle index is calculated by using rock physical parameters and mineral composition,and the advantages and disadvantages of the two are compared.Then a new formula for calculating brittleness index is obtained by combining rock physical parameters and mineral composition.Finally,the brittleness of high quality shale reservoir in Pengshui area is evaluated comprehensively.Compared with the measured brittleness,the new formula has good effect.The average brittleness index of the Wufeng-Long Section 1 is more than 70%in Nanchuan area,China.The lateral distribution is stable and the fracturing conditions are good.