Abstract: With low permeability but thick and widespread distribution,the pay sands in the upper Triassic Yanchang Series_6-8 in Ordos basin merit attention.Experiments for the increase of production have been conducted in the pilot area with the application of mercury-injection for pore structure study,examination of thin sections and infrared spectra and differential thermal and x-ray diffraction analyses for clay minerals determination,and wettability test and fissure counting of core samples,etc.These experiments reveal the structural characteristics of the Yanchang pay sands,on the basis of which the authors propose that hydraulic fracturing treatment of the sands is an effective measure for increasing production.

摘要： 鄂尔多斯盆地上三迭系延长统长_6-8为一套低渗油层,厚度大,分布广,但产油量很低。为采取相应的措施提高油井产量,开辟了一个试验区,进行了油层研究工作:用压汞法进行了孔隙结构研究;通过薄片、红外光谱、差热和X衍射等分析进行了粘土矿物鉴定;对岩心作了微细裂缝观察和润湿性试验;用图像分析仪对一些薄片进行了孔隙数量及面积的测定;通过电镜扫描对比了样品在不同液体注入前后孔隙结构的变化。通过这些工作揭示了长_6-8低渗油层的孔隙结构特征,为进行压裂增产试验提供了依据。