流体注入法定量表征页岩孔隙结构测试方法研究进展

Advances in quantitative characterization of shale pore structure by using fluid injection methods

页岩致密且结构复杂,对其孔隙结构进行定量表征一直是页岩储层研究的重点和难点,因其能够为页岩油气储层评价和甜点确定提供重要信息。通过系统梳理已有研究成果,介绍了以压汞法和气体吸附法为代表的流体注入法,简述了能够影响测试结果的因素,指出了目前页岩全孔径孔隙结构表征的问题及发展方向。分析表明,颗粒样气体吸附法和块(柱)压汞法表征结果的数据匹配性差,整合难度大;同时由上述两种方法联合所获得的表征结果也无法被其他独立测试所验证。进一步指出采用颗粒样代替传统块(柱)样进行页岩压汞测试可以提高数据质量,也是未来方法联用的发展方向,其中样品颗粒堆积孔进汞量校正、颗粒样粒径选择、多方法数据匹配是实现页岩全孔径孔隙结构定量表征的关键。

Shale is compact and has complex structure,which makes it hard to characterize its pore structure quantitatively;however,the pore structure of shale can provide important information for shale reservoir evaluation and sweet spot determination. The fluid injection methods,represented by the gas adsorption method and the mercury injection method,are the most commonly used techniques in shale pore structure characterization,but neither of them can provide the complete pore size range of shale. In this paper,the research results of previous studies were reviewed and summarized,and the key factors affect the test result of gas adsorption method and mercury injection method were analyzed. The problems and future directions in the combined characterization of shale pore structure in the complete pore size were pointed out. It is noted that the characterization results from the gas adsorption using particle samples do not match those from the mercury injection using bulk samples,which makes the data combination impossible. And the combined characterization results are hard to be verified. For mercury injection,the usage of particle samples can improve the data quality compared to the bulk ones,as well as the combined characterization results. The understandings about conformance correction,premium particle size and data compatibility are the key issues to improve the combined characterization of shale pore structure.