易破损疏松砂岩的数字岩心构建新方法

A new method of digital core construction for easily damaged unconsolidated sandstone

由于疏松砂岩的胶结程度较差,实验过程中容易破坏岩心的孔隙结构,实验结果可靠性较差;常规数字岩心构建流程包含的洗油、钻取小样等步骤依然会破坏疏松砂岩的孔隙结构。为解决疏松砂岩岩心实验难度大的问题,提出了一套数字岩心构建新方法。该方法通过冷冻保存疏松砂岩地层密闭取心,对含油岩心柱塞开展微米CT扫描、聚焦扫描,避免对岩心孔隙结构的破坏,在此基础上完成数字岩心的建立;该方法能够精确测试疏松砂岩物性及流动参数,实验结果与油田实际开发情况吻合较好,特别是与密闭取心饱和度分析结果基本一致,该方法减少了常规方法带来的实验误差并缩短了实验周期,可应用于类似储层的岩心分析。

Due to the poor cementation of unconsolidated sandstone,the pore structure of core is easy to be damaged in the process of experiment,but the reliability of experimental results is poor.The conventional digital core construction process includes oil washing,drilling small samples and other steps,which will still destroy the pore structure of unconsolidated sandstone.In order to solve the big difficulty existed in unconsolidated sandstone core experiment,a new method of digital core construction is proposed.With this method,the sealed coring of the unconsolidated sandstone formation is cryopreserved,and the micron CT scanning and focusing scanning are carried out on the oil-bearing core plunger to avoid the damage to the core pore structure.On this basis,the establishment of digital core is completed.This method can accurately test the physical properties and flow parameters of unconsolidated sandstone.The experimental results are in good accordance with the actual development of the oilfield,especially with the analysis results of closed coring saturation.This method not only reduces the experimental error caused by the conventional method,shortens the experimental cycle,but can be applied to the core analysis of similar reservoirs.