Determination of organic and inorganic hydrocarbon saturations and effective porosities in shale using vacuum-imbibition method

作者：Sang, Qian; Zhang, Shaojie; Li, Yajun; Dong, Mingzhe^*; Bryant, Steven

来源：International Journal of Coal Geology, 2018, 200: 123-134.

DOI：10.1016/j.coal.2018.10.010

• Vacuum-imbibition
• Organic oil saturation
• Inorganic oil saturation
• Organic porosity
• Inorganic porosity
• Total organic carbon

Shale oil is a significant unconventional energy resource worldwide. Shale formations are complex systems, with both inorganic and organic content and porosities. Oil saturation in a shale oil formation consists of two components: inorganic saturation (free oil-dominated) and organic saturation (ad- and absorbed oil-dominated). Shale porosity includes inorganic and organic porosities. There is no reported research that identifies the two porosities and saturations. We therefore recently performed, for the first time, two types of vacuum-imbibition tests - water imbibition and oil imbibition - on 20 shale oil rock samples to distinguish these two porosities and two saturations. In case of 100% oil saturated, the final imbibed oil volume in oil imbibition test represents the total oil content that a sample can hold, the final imbibed water volume in water imbibition test represents the inorganic content, and the difference between the two represents the organic content. Helium saturation tests were conducted to determine the total pore volume in shale rock samples. The content of ad- and absorbed oil is obtained from the difference between the total imbibed oil volume and the pore volume. The difference between the organic content and the ad - /absorbed oil content represents the organic pore volume, thereby obtaining the organic and inorganic porosities. Our results indicate that, for the shale rock samples tested, the maximum possible oil content in organic matter ranges from 6% to 55% of the total oil content, and 50% to 90% of the organic oil content is ad- and absorbed in kerogen. The organic porosity ranges from 2% to 50% of the total porosity. Both the organic oil saturation and the organic porosity exhibit a growing trend with total organic carbon of shale rock samples.

• 出版日期2018-12-1
• 单位中国石油大学（华东）