利用激发极化确定泥质砂岩渗透率的实验研究

An Induced Polarization Method for Estimating Permeability of Shaly Sand Reservoir

激发极化衰减谱与泥质砂岩储层的孔隙结构有密切的关系,因此可以用来求取渗透率,这个参数是油气生产的关键参数。本文的目的就是建立合理的模型,从而可以通过激发极化求取地层渗透率。采用四电极法测量了大庆油田123块岩心的激发极化衰减谱,通过反演得到相应的弛豫时间谱,建立了不同的渗透率求取模型,并对这些模型进行了讨论。结果表明与传统的通过孔隙度或者地层因素方法求取渗透率的模型相比,所建立的模型具有更高的精度,因而更适合于求取渗透率。

Time-domain Induced Polarization （IP） decay curve depends on pore structure of shaly sand reservoir and it can be used to estimate the permeability which is a determining factor for making production decision in petroleum industry. The purpose of this paper is to establish an ap- preciate model to estimate the permeability. IP decay curve measurements have been performed on 123 samples from Daqing oilfield using four-electrode technique. A singular value decomposition method was used to transform the IP decay data into the spectrum. Different models were established to estimate the permeability. The results of the research indicate that the IP measure- ments greatly improve statistical significance of permeability correlations. Compared to the tradi- tional method using porosity only or formation factor only, the constructed models which contain the IP relaxation time spectra have lower error factor. It is concluded that the models using the geometric mean time constant of the IP relaxation time spectrum combining with the porosity or the resistivity formation factor will be better to estimate the permeability of the shaly sand reser- voir in the downhole.