Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan
After a sandstone oilfield enters the high water-cut period, the viscosity of crude oil has an important influence on remaining oil distribution and waterflooding characteristics under the same factors of, e.g., reservoir quality and development methods. Based on a comprehensive interpretation of th...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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De Gruyter
2020-12-01
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| Series: | Open Geosciences |
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| Online Access: | https://doi.org/10.1515/geo-2020-0218 |
| _version_ | 1818587490369404928 |
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| author | Wang Jincai Fan Zifei Zhao Lun Chen Li Ni Jun Wang Chenggang Zhang Xiangzhong |
| author_facet | Wang Jincai Fan Zifei Zhao Lun Chen Li Ni Jun Wang Chenggang Zhang Xiangzhong |
| author_sort | Wang Jincai |
| collection | DOAJ |
| description | After a sandstone oilfield enters the high water-cut period, the viscosity of crude oil has an important influence on remaining oil distribution and waterflooding characteristics under the same factors of, e.g., reservoir quality and development methods. Based on a comprehensive interpretation of the waterflooded layers in new oil wells, physical simulation experiments, and reservoir numerical simulations, we analyzed the waterflooding laws of a high water-cut sandstone reservoir with different oil viscosities in Kazakhstan under the same oil production speed, and we clarified the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The results show that low-viscosity oil reservoirs (1 mPa s) have uniform waterflooding, thick streamlines, small waterflooding areas, and low overall waterflooding degrees because of their homogeneous oil–water viscosities. However, within waterflooded areas, the reservoirs have high oil displacement efficiencies and high waterflooding degrees, and the remaining oil is mainly concentrated in the unwaterflooded areas; therefore, the initial production and water cut in new oil wells vary significantly. High-viscosity oil reservoirs (200 mPa s) have severe waterflooding fingering, large waterflooding areas, and high overall waterflooded degrees because of their high oil–water mobility ratios. However, within waterflooded areas, the reservoirs have low oil displacement efficiencies and low waterflooding degrees, and the remaining oil is mainly concentrated in both the waterflooded areas and the unwaterflooded areas; therefore, the differences in the initial production and water cut of new oil wells are small. Moderate-viscosity oil reservoirs (20 mPa s) are characterized by remaining oil distributions that are somewhere in between those of the former two reservoirs. Therefore, in the high water-cut period, as the viscosity of crude oil increases, the efficiency of waterflooding gradually deteriorates and the remaining oil potential increases. In the later development, it is suggested to implement the local well pattern thickening in the remaining oil enrichment area for reservoirs with low viscosity, whereas a gradual overall well pattern thickening strategy is recommended for whole reservoirs with moderate and high viscosity. The findings of this study can aid better understanding of waterflooding law and the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The research results have important guidance and reference significance for the secondary development of high water-cut sandstone oilfields. |
| first_indexed | 2024-12-16T09:09:41Z |
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| id | doaj.art-dde167e234b84e07a82cfe63714f0de7 |
| institution | Directory Open Access Journal |
| issn | 2391-5447 |
| language | English |
| last_indexed | 2024-12-16T09:09:41Z |
| publishDate | 2020-12-01 |
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| spelling | doaj.art-dde167e234b84e07a82cfe63714f0de72022-12-21T22:37:01ZengDe GruyterOpen Geosciences2391-54472020-12-011211736174910.1515/geo-2020-0218geo-2020-0218Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in KazakhstanWang Jincai0Fan Zifei1Zhao Lun2Chen Li3Ni Jun4Wang Chenggang5Zhang Xiangzhong6Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaAfter a sandstone oilfield enters the high water-cut period, the viscosity of crude oil has an important influence on remaining oil distribution and waterflooding characteristics under the same factors of, e.g., reservoir quality and development methods. Based on a comprehensive interpretation of the waterflooded layers in new oil wells, physical simulation experiments, and reservoir numerical simulations, we analyzed the waterflooding laws of a high water-cut sandstone reservoir with different oil viscosities in Kazakhstan under the same oil production speed, and we clarified the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The results show that low-viscosity oil reservoirs (1 mPa s) have uniform waterflooding, thick streamlines, small waterflooding areas, and low overall waterflooding degrees because of their homogeneous oil–water viscosities. However, within waterflooded areas, the reservoirs have high oil displacement efficiencies and high waterflooding degrees, and the remaining oil is mainly concentrated in the unwaterflooded areas; therefore, the initial production and water cut in new oil wells vary significantly. High-viscosity oil reservoirs (200 mPa s) have severe waterflooding fingering, large waterflooding areas, and high overall waterflooded degrees because of their high oil–water mobility ratios. However, within waterflooded areas, the reservoirs have low oil displacement efficiencies and low waterflooding degrees, and the remaining oil is mainly concentrated in both the waterflooded areas and the unwaterflooded areas; therefore, the differences in the initial production and water cut of new oil wells are small. Moderate-viscosity oil reservoirs (20 mPa s) are characterized by remaining oil distributions that are somewhere in between those of the former two reservoirs. Therefore, in the high water-cut period, as the viscosity of crude oil increases, the efficiency of waterflooding gradually deteriorates and the remaining oil potential increases. In the later development, it is suggested to implement the local well pattern thickening in the remaining oil enrichment area for reservoirs with low viscosity, whereas a gradual overall well pattern thickening strategy is recommended for whole reservoirs with moderate and high viscosity. The findings of this study can aid better understanding of waterflooding law and the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The research results have important guidance and reference significance for the secondary development of high water-cut sandstone oilfields.https://doi.org/10.1515/geo-2020-0218kazakhstanhigh water-cut sandstone reservoiroil viscositywaterfloodingremaining oildevelopment measures |
| spellingShingle | Wang Jincai Fan Zifei Zhao Lun Chen Li Ni Jun Wang Chenggang Zhang Xiangzhong Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan Open Geosciences kazakhstan high water-cut sandstone reservoir oil viscosity waterflooding remaining oil development measures |
| title | Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan |
| title_full | Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan |
| title_fullStr | Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan |
| title_full_unstemmed | Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan |
| title_short | Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan |
| title_sort | effects of oil viscosity on waterflooding a case study of high water cut sandstone oilfield in kazakhstan |
| topic | kazakhstan high water-cut sandstone reservoir oil viscosity waterflooding remaining oil development measures |
| url | https://doi.org/10.1515/geo-2020-0218 |
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