微孔隙对低孔低渗砂岩储集层测井评价的影响——以苏里格气田A区块盒8段储集层为例

在低孔低渗砂岩储集层中，微孔隙给岩石的导电性及物性参数的评价带来了一定的困难。以苏里格气田A区块盒8段储集层为例，将动力与阻力平衡时所得到的孔隙半径0.15 μm作为微孔隙的上限，通过数值模拟及数理统计等手段解释了研究区的“非阿尔奇”现象。研究表明，孔隙类型决定微孔隙发育比例，孔隙度越大，微孔隙比例越小；随着微孔隙比例增大，渗透率明显降低；微孔隙发育的低孔低渗砂岩储集层具有中子孔隙度明显增大、密度和声波时差变化较小的特点，且随着黏土含量增多，束缚水饱和度增高，导电网络发育，导电性增强，电阻率降低。所以，微孔隙发育是研究区低孔低渗砂岩储集层出现低阻的主要原因。

Influence of Micropores Occurrence on Logging Evaluation in Low Porosity and Low Permeability Sandstone Reservoirs:A Case Study of He-8 Member in Block A of Sulige Gas Field

In low porosity and low permeability sandstone reservoirs, the development of micropores bring some difficulties to the evaluation of rock conductivity and petrophysical parameters. Taking Block A in Sulige gas field as an example, the micropore limit in this field is redetermined as 0.15 μm by means of the principle of balanced dynamics and resistance, and the "non?Archie" phenomenon is explained by numerical simulation and mathematical statistics. The studies show that the pore type determines proportion of micropores, and the big?ger the porosity, the smaller the proportion of micropores; with the proportion of micropores increasing, the permeability is obviously decreased; the sandstone reservoir with low porosity and permeability is characterized by significantly increamental neutron porosity and small changes of the density and the interval transit time, and with the increase of clay content, the irreducible water saturation increases,the conductive network develops, conductivity enhances, and the resistivity decreases. Therefore, the micropores occurrence is the main reason for the low resistivity phenomenon appeared in the low porosity and low permeability reservoirs in this area