Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential origin
The micro-nano pore throat system widely developed in tight sandstone is the essential difference between tight sandstone reservoir and conventional sandstone reservoir; it is also the main factor affecting the seepage characteristics and development effect of tight sandstone reservoir. This thesis...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2020-04-01
|
| Series: | Journal of Natural Gas Geoscience |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2468256X20300043 |
| _version_ | 1797764322529640448 |
|---|---|
| author | Wei Wang Yushuang Zhu Caili Yu Le Zhao Dayou Chen |
| author_facet | Wei Wang Yushuang Zhu Caili Yu Le Zhao Dayou Chen |
| author_sort | Wei Wang |
| collection | DOAJ |
| description | The micro-nano pore throat system widely developed in tight sandstone is the essential difference between tight sandstone reservoir and conventional sandstone reservoir; it is also the main factor affecting the seepage characteristics and development effect of tight sandstone reservoir. This thesis analyzed the pore-throat types and distributions of the Chang 6 and the Chang 7 reservoirs in the Jiyuan area of the Ordos Basin and discussed the original causes by cast section, SEM, and constant-rate mercury injection. The results showed that the pore type of the Chang 6 reservoir is predominantly residual intergranular pores wherein the throat is mostly compacted. The pore of Chang 6 is more developed than the throat. The pore type of the Chang 7 reservoir is mainly feldspar solution pores, whereas its throat is mostly dissolution. The throat of Chang 7 is more developed than pore. The pore radius distribution range and the average value of the Chang 6 reservoir are similar to those of the Chang 7 reservoir. The distribution range and average value of the throat radius of the Chang 6 reservoir are obviously larger than that of the Chang 7 reservoir. Meanwhile, the physical property of the Chang 6 reservoir is better than that of the Chang 7 reservoir. The Chang 6 reservoir is located in delta sedimentary with shallow burial depth. The high chlorite membrane content and low compaction strength of the Chang 6 reservoir make it more conducive to maintaining the original sedimentary pore space; the dissolution further enlarges the pore space. The Chang 7 reservoir is located in a semi-deep lake sedimentary with large burial depth. The compaction and cementation of the Chang 7 reservoir are strong, and the original sedimentary pore space is massively compressed. Although dissolution strongly occurs in the later stage, the connectivity and seepage capacity of the throat of dissolution origin are lower than those of compaction origin. Dissolution can increase reservoir space; nevertheless, it cannot significantly improve seepage capacity. Therefore, there is a significant difference in permeability of the two successive layers. |
| first_indexed | 2024-03-12T19:54:43Z |
| format | Article |
| id | doaj.art-86938bfb854f4c30b455ddc280a6ee66 |
| institution | Directory Open Access Journal |
| issn | 2468-256X |
| language | English |
| last_indexed | 2024-03-12T19:54:43Z |
| publishDate | 2020-04-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Journal of Natural Gas Geoscience |
| spelling | doaj.art-86938bfb854f4c30b455ddc280a6ee662023-08-02T02:53:53ZengKeAi Communications Co., Ltd.Journal of Natural Gas Geoscience2468-256X2020-04-01524555Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential originWei Wang0Yushuang Zhu1Caili Yu2Le Zhao3Dayou Chen4School of Chemistry and Chemical Engineering, Yulin University, Yulin, 719000, China; Corresponding author.Department of Geology, Northwest University, Xi'an, 710069, China; Corresponding author.Oil Production Plant No.1, PetroChina Changqing Oilfield Company, Yan'an, 716000, ChinaOil Production Plant No.1, PetroChina Changqing Oilfield Company, Yan'an, 716000, ChinaBailie School of Petroleum Engineering, Lanzhou City University, Lanzhou, 730070, ChinaThe micro-nano pore throat system widely developed in tight sandstone is the essential difference between tight sandstone reservoir and conventional sandstone reservoir; it is also the main factor affecting the seepage characteristics and development effect of tight sandstone reservoir. This thesis analyzed the pore-throat types and distributions of the Chang 6 and the Chang 7 reservoirs in the Jiyuan area of the Ordos Basin and discussed the original causes by cast section, SEM, and constant-rate mercury injection. The results showed that the pore type of the Chang 6 reservoir is predominantly residual intergranular pores wherein the throat is mostly compacted. The pore of Chang 6 is more developed than the throat. The pore type of the Chang 7 reservoir is mainly feldspar solution pores, whereas its throat is mostly dissolution. The throat of Chang 7 is more developed than pore. The pore radius distribution range and the average value of the Chang 6 reservoir are similar to those of the Chang 7 reservoir. The distribution range and average value of the throat radius of the Chang 6 reservoir are obviously larger than that of the Chang 7 reservoir. Meanwhile, the physical property of the Chang 6 reservoir is better than that of the Chang 7 reservoir. The Chang 6 reservoir is located in delta sedimentary with shallow burial depth. The high chlorite membrane content and low compaction strength of the Chang 6 reservoir make it more conducive to maintaining the original sedimentary pore space; the dissolution further enlarges the pore space. The Chang 7 reservoir is located in a semi-deep lake sedimentary with large burial depth. The compaction and cementation of the Chang 7 reservoir are strong, and the original sedimentary pore space is massively compressed. Although dissolution strongly occurs in the later stage, the connectivity and seepage capacity of the throat of dissolution origin are lower than those of compaction origin. Dissolution can increase reservoir space; nevertheless, it cannot significantly improve seepage capacity. Therefore, there is a significant difference in permeability of the two successive layers.http://www.sciencedirect.com/science/article/pii/S2468256X20300043Ordos BasinTight sandstone reservoirMicroscopic pore structureConstant-rate mercury injectionDissolution |
| spellingShingle | Wei Wang Yushuang Zhu Caili Yu Le Zhao Dayou Chen Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential origin Journal of Natural Gas Geoscience Ordos Basin Tight sandstone reservoir Microscopic pore structure Constant-rate mercury injection Dissolution |
| title | Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential origin |
| title_full | Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential origin |
| title_fullStr | Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential origin |
| title_full_unstemmed | Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential origin |
| title_short | Pore size distribution in the tight sandstone reservoir of the Ordos Basin, China and their differential origin |
| title_sort | pore size distribution in the tight sandstone reservoir of the ordos basin china and their differential origin |
| topic | Ordos Basin Tight sandstone reservoir Microscopic pore structure Constant-rate mercury injection Dissolution |
| url | http://www.sciencedirect.com/science/article/pii/S2468256X20300043 |
| work_keys_str_mv | AT weiwang poresizedistributioninthetightsandstonereservoiroftheordosbasinchinaandtheirdifferentialorigin AT yushuangzhu poresizedistributioninthetightsandstonereservoiroftheordosbasinchinaandtheirdifferentialorigin AT cailiyu poresizedistributioninthetightsandstonereservoiroftheordosbasinchinaandtheirdifferentialorigin AT lezhao poresizedistributioninthetightsandstonereservoiroftheordosbasinchinaandtheirdifferentialorigin AT dayouchen poresizedistributioninthetightsandstonereservoiroftheordosbasinchinaandtheirdifferentialorigin |