Oil Heterogeneity Characteristics of Low Oil Saturation Sandstone Reservoirs in M Area of Junggar Basin
The second member of Sangonghe formation in M area, Junggar basin is a typical sandstone reservoir with low oil saturation. The oil heterogeneity in the upper vertical sandstone body is obvious, and the relationship between four properties is unclear, which increases the difficulty of reservoir effe...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Office of Well Logging Technology
2023-08-01
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| Series: | Cejing jishu |
| Subjects: | |
| Online Access: | https://www.cnpcwlt.com/#/digest?ArticleID=5516 |
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| Summary: | The second member of Sangonghe formation in M area, Junggar basin is a typical sandstone reservoir with low oil saturation. The oil heterogeneity in the upper vertical sandstone body is obvious, and the relationship between four properties is unclear, which increases the difficulty of reservoir effectiveness evaluation and fluid identification. Based on the oil test results, oil-bearing description, thin section of rock, physical property test, high pressure mercury injection and well logging data, oil heterogeneity is characterized and oil-bearing strips are divided. The relationship between different oil strips and their lithology, physical property and electrical response is analyzed and determined. The results show that the strips of different oil-bearing levels in a single sandstone body in the second member of the Sangonghe formation are frequently interbedded. According to the information of oil test results and oil-bearing level, three categories and five subcategories of oil-bearing strips (I1, I2, II1, II2 and III) can be divided. Type I strips are mainly pure fine sandstone and coarse sandstone, with high structural maturity, large pore throat radius, good physical properties, porosity is greater than 11.0%, permeability is greater than 7.0mD; the type II strips fine sandstone and medium-fine sandstone are in the majority, and the porosity and permeability are distributed in 6.0% ~ 11.0% and 0.2 ~ 7.0mD; the type III strips is mostly fine sandstone (containing calcareous/argillaceous/silty), and the pores structure are not developed. Acoustic and deep induction resistivity are used to identify the differences in physical properties and fluid between the strips. Among them, the type I strips acoustic is greater than 68.5μs/ft, the I1 class strips deep induction resistivity range from 14.0to 18.5Ω・m, class I2 strips with less than 14.0Ω・m. The fine division of oil-bearing strips can effectively characterize the oil-bearing heterogeneity in low oil saturation sandstone reservoirs, and clarify its relationship with lithology, physical properties and electrical response, which also provides a basis for reservoir effectiveness evaluation, fluid property identification and reserve calculation. |
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| ISSN: | 1004-1338 |