页岩气储层Ramirez体积物理模型的改进

Improvement of Ramirez's petrophysical model for volume of shale gas reservoir

通过分析Ramirez等提出的页岩气储层体积物理模型,针对该模型没有划分黏土矿物的缺点,建立了黄铁矿含量与有机碳含量(TOC)的关系,并把利用多元统计方法评价的TOC结果作为模型输入参数的方式,进一步将该模型的无机矿物直接划分为黏土矿物、黄铁矿和其他矿物,弥补了该模型在黏土矿物变化大的层段计算精度低的缺陷,并简化了通过对无机矿物骨架与无机矿物孔隙中流体测井响应同时进行迭代的复杂求解过程。利用改进的Ramirez体积模型对实际资料进行了处理,计算结果表明:改进的模型比原模型计算的有机碳含量、孔隙度及含水饱和度更接近相应的岩心分析数据;其评价的黏土含量同样与岩心分析数据吻合良好,从而验证了改进的Ramirez体积模型的准确性与可靠性,为页岩气勘探、开发和储量计算提供了可靠资料。

Ramirez＇s petrophysical model for volume of shale gas reservoir is disadvantageous for no division of the clay mineral matrix.This study establishes a relationship between the contents of pyrite and total organic carbon （TOC） in core samples and then takes TOC estimated by multivariate statistical analysis as the input parameter of Ramirez＇s model.The mineral matrix of the model is further divided into clay,pyrite,and other minerals.This offsets the defect of the model regarding the low calculation accuracy when used for shale gas reservoir intervals with substantial changes in the clay mineral matrix.It also simplifies the complex solution iteratively by incorporating logging responses of inorganic mineral skeleton and fluids in inorganic mineral pores.The effectiveness and reliability of the improved petrophysical model are verified by core measurements.The TOC,porosity,and water saturation estimated by the improved model are closer to the measured core data,as well as the clay content.The results provide reliable information for shale gas exploration,development,and reserve calculation.