中东YL-DS油田高含泥质灰岩储层(泥质含量3,~8,)电阻率低,常规解释的含水饱和度较高,按纯灰岩储层段流体评价标准常被判定为水层.本研究避开对难以量化表征的纯灰岩骨架中束缚水的直接求取,通过计算储层中的泥质束缚水孔隙度来直接校正常规含水饱和度,简单易行,在实践中取得了良好的效果.具体方法为:根据纯泥岩的简化模型计算纯泥岩孔隙度,然后采用能谱测井资料计算干黏土的密度值,计算泥质灰岩储层中的泥质束缚水孔隙度,对常规阿尔奇公式计算的水饱和度进行泥质束缚水饱和度校正而获得视纯灰岩含水饱和度,最后采用校正后的含水饱和度和纯灰岩段标准解释图版综合判断储层流体性质.

Argilliferous limestone reservoirs usually are of high argillaceous content (3,~8,) but low logging resistiv-ity values in YL-DS Oil Field,Middle East.Interpreted as high water saturation by the conventional logging method,they are likely mistakably judged as aquifers according to the evaluation standard for the pure carbonate reservoirs.A simple available method of correctly identifying what the fluids are in argilliferous limestone reservoirs according to spectral log data and other calculations is put forward and successfully applied in this oil field.The method is:(1) ana-lyze clay types by spectral log data and estimate density of dry clay;(2) calculate porosity of pure mudstone by the simplified mudstone model,and then calculate the porosity related with argillaceous bound water in the argilliferous limestone reservoirs; (3) correct argillaceous bound water saturation with the water saturation calculated by normal Archieˊs formula to obtain water saturation in apparent pure limestone; and (4) comprehensively identify fluid types by the corrected pure limestone saturation and the standard cross-plot of pure limestone reservoirs.