利用测井资料计算阳离子交换量Q_v的方法对比

Comparation of Calculating Methods of Cation Exchange Capacity Q_v Using Logging Data

为了准确计算泥质砂岩储层的Qv,提出了利用核磁共振测井计算Qv的方法,通过对56块同时具有阳离子交换量和孔隙度、渗透率数据的岩心样品的分析,建立了阳离子交换量与综合物性指数的关系模型。为了解决准确而连续地计算综合物性指数的问题,提出了利用核磁共振测井横向驰豫时间几何平均值求取Swanson参数、进而利用Swanson参数获取综合物性指数的方法。同时利用核磁共振测井法、自然伽马测井相对值法、自然电位测井图版法3种计算Qv的方法对准噶尔盆地南缘4口井资料进行了处理,并对处理结果作了对比分析。结果表明:在泥质砂岩厚层段,3种方法都可以简单而有效地计算Qv。与岩心资料相比,核磁共振测井法计算的相对误差为13%,自然伽马测井法计算的相对误差为19%,自然电位测井法计算的相对误差为22%;在砂泥岩薄互层,用核磁共振测井法计算的Qv比其它两种方法计算的结果更为可靠,更能反映地层的真实情况。

In order to accurately calculate the cation exchange capacity Qv of shaly sand reservoirs,a Qv calculating method using NMR logging data was presented,a correlation model between Qv and synthesized index was established by analyzing 56 core samples with porosity,permeability and CEC,considering the problem that it was difficult to accurately calculate synthesized index,the novel method was presented to calculate Swanson parameter from NMR T2 geometric mean value and to obtain the synthesize index from Swanson parameter.At the same time the data of four wells at the southern margin of Junggar Basin were processed using Qv calculated by three different methods of NMR logging,natural gamma ray logging and spontaneous potential logging,and comparative analysis was carried out.It is showed that Qv can be simply and efficiently calculated by these three methods in thick layers of shaly sand,compared with the core analysis results,the relative error based on NMR logging,natural gamma ray logging and spontaneous potential logging respectively is 13%,19% and 22%;in thin alternating layers of shale and sandstone,Qv calculated using NMR logging is more reliable than that calculated by the other two methods,and better reflects the true situation of formations.