渝东南地区页岩润湿性的定量表征研究

Research of quantitative characterization based on shale wet-ability in southeast Chongqing area

以渝东南地区五口井页岩为研究对象,采用光学接触角测试方法测试其润湿性,并对比分析页岩润湿性特性与地层压力系数、解析速率、黏土含量、TOC之间的相关性,找出不同页岩储层间润湿性变化特点,总结影响页岩润湿性变化的可能因素。最终得出研究结果:①常压井的白油/岩石的平均接触角相对较低,即更具有亲油性;超压井的水/岩石的接触角较低,即更具有亲水性;②在解析速率方面,发现高解析速率的页岩气井的亲水、亲油的程度均高于低解析速率的页岩气井;③页岩TOC越高,其亲油程度越高,但亲水性影响不大,表明有机质含量与亲油性存在直接联系。最后,利用杨氏方程,通过界面张力来定量表征岩石的润湿性特点,可用于接触角法评价页岩润湿性的应用研究。

Using five shale Wells in southeast of Chongqing area as the research object,by optical contact angle test method to test its wet-ability,and comparatively analysis the correlation between shale wet-ability characteristicsand formation pressure coefficient,resolution rate,clay content and TOC,in order to find out the difference between shale reservoir wet-ability change characteristic,summarizes the possible factors that result in the change of wet-ability of shale.The experimental results show that:①the white oil/rock contact angle of atmospheric pressure wells is relatively low,that is,it is more oleophilic.The over-pressure has a lower contact angle of water/rock,which is more hydrophilic.②In terms of analytical rate,it is found that shale gas wells with high analytical rate are more water-wet and oil-wet than shale gas wells with low analytical rate.③The higher the TOC content,the higher the degree of oil-wet,but the hydrophilic effect is not significant,indicating that the organic matter content is directly related to the lipophilicity.Finally,Young’s equation is used to quantitatively characterize rock wet-ability through inter-facial tension,which can be used to evaluate the wet-ability of shale by contact angle method.