CEC比值法在凝灰质砂岩储层测井评价中的应用——以海-塔盆地X凹陷凝灰质砂岩储层为例

Application of the CECratio method in evaluation of tuffaceous sandstone reservoirs:an example in the X depression of Hailar-Tamtsag basin

凝灰质砂岩储层一直是测井评价中的难点.凝灰质的存在使储层的孔隙结构和物性变化都很大,其含量直接影响储层参数的求取,对储层饱和度的影响不容忽视.本文以海-塔盆地X凹陷的凝灰质砂岩储层为例进行测井评价研究.基于泥质和凝灰质的测井响应差异利用粒子群和细菌觅食的混合优化算法计算储层中两者的含量,然后通过阳离子交换量(CEC)的实验数据验证了凝灰质具有导电性,进而利用CEC与电阻率之间的关系得到凝灰质电阻率的计算方法,并且应用到饱和度的计算,最终得到了一种新的计算凝灰质砂岩储层饱和度的方法——CEC比值法,并取得了良好的应用效果.

The logging evaluation of tuffaceous sandstone reservoirs remains a challenge in hydrocarbon exploration.The existence of tuff results in great variations in reservoir pore structure and associated physical properties,strongly influencing the formation parameters.Therefore,the effect of tuff on saturation models cannot be ignored.This study takes the tuffaceous sandstone reservoirs in the X depression of the Hailar-Tamtsag basin as an example to analyze this problem.Based on the differences of response characteristics between tuff and shale,the component content is calculated with the method which combines bacterial foraging algorithm and particle swarm optimization algorithm.The experimental data of cation exchange capacity（CEC）proves that tuff has conductivity.And then the resistivity of tuff is obtained by using the relationship between CECand resistivity,which is used to calculate the saturation.Finally,the new method is proposed to calculate the saturation of tuffaceous sandstone reservoirs,which isnamed the CECratio method.The calculation results of this method have a good application effect.