砂砾岩电阻率与岩石力学参数相关性研究

为研究电阻率与岩石力学参数之间的相关关系，以准噶尔盆地西北缘某区块致密砂砾岩储层为研究对象，在岩石波速与力学参数之间具有确定关系的基础上，对比了常规测井资料中3条电阻率曲线与声波时差的相关性，提出了基于原状地层电阻率的砂砾岩储层岩石力学参数计算模型。研究结果表明:电阻率与声波时差的相关性较好，钻井液的侵入会影响二者的相关性，适宜采用原状地层电阻率预测岩石的力学参数；采用新模型得到的全井段岩石力学参数预测结果均方差和平均相对误差均小于法斯特公式和对数模型，特别是在纯砂砾岩段，采用新模型得到的预测结果误差比法斯特模型降低了50%以上，拟合效果显著提升。应用实例表明，采用新模型与采用声波时差及密度获得的岩石力学参数进行对比，误差小于10%。研究表明该模型能够在无声波测井条件下为致密砂砾岩储层岩石力学参数评估提供参考。

Study on correlation between glutenite resistivity and rock mechanical parameters

In order to study the correlation between resistivity and rock mechanical parameters, a tight glutenite reservoir in some block on the northwestern margin of the Junggar Basin was taken as the research object. On the basis of the definite relationship between rock wave velocity and mechanical parameters, the correlations between the three resistivity curves in conventional logging data and the acoustic interval transit time were compared, and a model calculating rock mechanical parameters for glutenite reservoirs based on the in-situ resistivity of the formation was proposed. The research results show that the correlation between resistivity and acoustic interval transit time is good, and the invasion of drilling fluid will affect the correlation between the two, so it is suitable to use the in-situ resistivity of the formation to predict the mechanical parameters of the rock; the mean square error and average relative error of the predicted rock mechanical parameters obtained by the new model are smaller than those of the Faust formula and the logarithmic model, especially in the pure glutenite section, the error of the predicted results obtained by the new model is reduced by more than 50% compared with Faust model, with significant improvement in fitting effect. The case application shows that when comparing with the mechanical parameters obtained by acoustic interval transit time and density, the error of the mechanical parameters obtained by the new model is less than 10%. The research shows that the model can provide a reference for evaluating rock mechanical parameters of tight glutenite reservoirs under the conditions of lacking sonic logging.