论文详情
复电阻率/电导率是电磁勘探描述地下岩石电性的重要参数之一,但地层条件下(高温、高压环境)的岩石电导率会发生显著变化。为研究页岩复电导率在温度、压力作用下的变化规律,根据电导模型及界面双电层等理论建立了页岩电导率频散模型,推导了岩石电导率随地层深度变化的关系。并通过一组页岩模拟地层环境的复电导率,结合模型和数据拟合确定了该组页岩的模型参数,建立了研究靶区页岩随地层温度、压力变化的电导率模型。提出了岩石特征孔隙度,可用于预测岩石电导率随深度变化的趋势。综合理论分析和实验结果认为,随地层压力和温度变化的电导率模型可以有效提高实验数据对实际地层的适用性,理论模型对页岩的实验数据具有较高的拟合度,也为该模型应用于其它岩性或地区提供了实验基础。
Complex resistivity(or conductivity) is an important parameter to describe the electrical properties of underground rocks in electromagnetic exploration.The conductivity of rock will change significantly under stratigraphic conditions(i.e.,at high temperature and high pressure).To study how the complex conductivity of shale varies under the action of temperature and pressure,a shale conductivity dispersion model was established based on the conductance model and the interface double electric layer.Based on the dispersion model,the relationship between rock conductivity and formation depth was then deduced.Moreover,a complex conductivity experiment was carried out to simulate the formation environment in shale.The model parameters were determined by fitting the model and experimental data,and the model of conductivity in shale according to temperature and pressure in the study area was established.The characteristic porosity of rock was proposed,which can be used to predict the trend of rock conductivity with depth.The model of conductivity in the formation according to temperature and pressure can effectively improve the applicability of experimental data to actual strata.The theoretical model has a high fitting degree for experimental data of shale,but also provides an experimental basis for the application of the model to other lithologies or regions.
国家重点研发计划项目(2018YFC0603302)资助。