石油实验地质2025，Vol.47Issue(4)：742-753,12.DOI:10.11781/sysydz2025040742
川东南林滩场五峰组—龙马溪组深层页岩气储层脆性定量评价
Quantitative evaluation of brittleness of deep shale gas reservoirs of Wufeng-Longmaxi formations in Lintanchang area,southeastern Sichuan Basin
摘要
Abstract
With the increase in rock plasticity of deep shale gas reservoirs,their brittleness characteristics become difficult to be accurately characterized using traditional evaluation methods.Taking the deep shale gas reservoirs from the upper Ordovician Wufeng Formation to the first member of Lower Silurian Longmaxi Formation in the Lintanchang area of the southeastern Sichuan Basin as a case study,triaxial rock mechanics and fracture tough-ness experiments on shale samples were conducted.Based on the experimental results,a comprehensive quantita-tive evaluation of reservoir brittleness was carried out using deep learning.The experimental results showed that with the increasing temperature and pressure,the Young's modulus,Poisson's ratio,and compressive strength of the shale samples all increased.The brittleness of shale samples from layer①was significantly lower than that of samples from layer③.Shale samples with better brittleness exhibited obvious fluctuations in the stress-strain curves,showed nonlinear deformation characteristics,and had relatively small residual strain values.The fracture toughness of shale samples was closely related to the content of brittle minerals,and the fracture toughness values of typeⅠand typeⅡsamples with laminations perpendicular to bedding planes were relatively lower.Based on the shale characteristics of mineral composition,triaxial rock mechanics,and fracture toughness,a deep learning weight analysis model was developed using brittleness indices Bel and Bmine3 and fracture toughness index IKIC as data inputs.The cumulative risk value was less than 5,indicating the high reliability of the model.A comprehen-sive brittleness index B was established based on the model,and its correlation with the measured brittleness index BS of core samples was significantly improved(R=0.852 7).The quantitative brittleness evaluation results truly reflect the vertical profile of brittleness characteristics in deep shale reservoirs.The reservoirs at layer ③bottom and layer②in the Wufeng-Longmaxi formations of the study area exhibit relatively better brittleness and lower fracture toughness index,making them preferred target layers for future exploration and development.关键词
深层页岩储层/三轴岩石力学/断裂韧性/深度学习权重分析法/综合脆性指数/五峰组—龙马溪组/四川盆地Key words
deep shale reservoir/triaxial rock mechanics/fracture toughness/deep learning weight analysis method/comprehensive brittleness index/Wufeng-Longmaxi formations/Sichuan Basin分类
能源科技引用本文复制引用
冯少柯,熊亮,尹帅,董晓霞,魏力民..川东南林滩场五峰组—龙马溪组深层页岩气储层脆性定量评价[J].石油实验地质,2025,47(4):742-753,12.基金项目
中国石化科技部项目(P21042-1、P23221)资助. （P21042-1、P23221）
