火山岩含气储层有效孔隙度确定方法

火山岩储层矿物成分复杂多样,岩性对常规测井影响很大,又由于储层含气,应用常规测井曲线计算孔隙度难度大。而核磁共振测井受骨架影响小,克服了以体积模型为基础的传统测井方法受岩性影响的缺陷。由于储层含气含氢指数小,导致气层核磁共振测井计算的有效孔隙度小于地层孔隙度,含气显示越好的储层核磁测井解释的有效孔隙度越小。而密度曲线由于储层含气密度值降低,导致密度孔隙度偏高。应用上述两参数组合可以对火山岩含气储层的有效孔隙度进行含气校正。通过岩心刻度测井的方法进行权系数标定,校正储层含气对孔隙度的影响。

A METHOD TO DETERMINE EFFECTIVE POROSITY IN VOLCANIC RESERVOIR

Because mineralogical components in volcanic reservoirs are complex, lithology has much impact on conventional logging menthods, and the reservoirs contain gas, it is difficult to calculate porosity with conventional logs.The matrix has little impact on nuclear magnetic resonance logging, which can overcome the shortcomings of conventional logging methods that are based on the volume model.As small gas and hydrogen index causes the calculated effective porosity of a gas zone smaller than that of formation, the more gas there is, the smaller effective porosity is through nuclear magnetism logging interpretation .Whereas density value of a density curve in gas reservoir decreases as density porosity increase.The effective porosity of a volcanic gas reservoir can be calibrated with combination of these two parametere.The weight coefficient can be defined through core calibration to correct the effect on porosity.