Shale porosity measurement by the saturated oil method: Removing the contribution from oils dissolved in kerogen

作     者：Jin-Bu Li Min Wang Hao-Ming Shao Ming Li Liang Liu Shuang-Fang Lu 

作者机构：National Key Laboratory of Deep Oil and GasChina University of Petroleum(East China)Qingdao 266580ShandongChina Shaanxi Key Laboratory of Petroleum Accumulation GeologyXi'an 710000ShaanxiChina Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences)Ministry of EducationWuhan 430074HubeiChina Sanya Offshore Oil&Gas Research InstituteNortheast Petroleum UniversitySanya 572025HainanChina 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2023年第20卷第6期

页      面：3273-3279页

核心收录：

学科分类：0710[理学-生物学] 0820[工学-石油与天然气工程] 081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 0703[理学-化学] 

基　　金：funded by the National Natural Science Foundation of China(42102154,41922015,42072147) Postdoctoral Research Foundation of China(2021M690168) Postdoctoral Innovative Talent Support Program of Shandong Province(SDBX2021004) Open Fund of Shaanxi Key Laboratory of Petroleum Accumulation Geology(PAG-2021-02) Open Funds of the Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences)(TPR-2021-02) Fundamental Research Funds for the Central Universities(20CX06085A) Qingdao Postdoctoral(ZX20210070). 

主　　题：Shale Porosity Oil saturation Kerogen-dissolved oil Water saturation 

摘      要：Shale porosity measurements have crucial scientific and economical applications in unconventionalpetroleum systems. As a standard technique, liquid saturation methods, including water saturation (WS)and oil saturation (OS), have been widely used to measure the porosity of many rock types. For clay-richshale reservoirs with high organic matter content, it is well known that the WS method may cause clayswelling and induce structural changes in the pore system. The OS method affects the accuracy ofporosity measurements because of some of the oil being dissolved by kerogen within the shale;however,this has not received sufficient research attention. In this study, we compare the previously reported andnewly tested OS porosities with helium (He) expansion porosity. Results show that OS porosity generallyexceeds the He porosity. Furthermore, the higher the total organic carbon (TOC) content and lower thematurity of shale, the greater the difference between the OS and helium porosities. When using the OSmethod, the effect of kerogen-dissolved oil causes an overestimation of the shale porosity by ~30%. To thebest of our knowledge, this is the first time to note the kerogen-dissolve oil effects on OS porosity. Herein,we propose a new, simple, and effective correction method for estimating OS porosity that involvessubtracting the kerogen-dissolved oil content from raw OS porosity. In addition, the quantification modelof kerogen-dissolved oil capacity is established, taking into account the abundance and maturity oforganic matter. Taking the He porosity as the benchmark, the absolute error of the corrected OS porositydoes not exceed 1% and the average relative error is only ~10%. The obtained results can help improve theaccuracy of shale porosity evaluation methods.