Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocity
The accurate morphology identification of gas hydrate-bearing sediments (GHBS) has great significance in practical exploitation and subsequent resource evaluation. Previous studies have disclosed two main morphologies for gas hydrate in sediments: pore- and fracture-filling. However, the existing id...
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| Format: | Article |
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Elsevier
2021-11-01
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| Series: | Energy Reports |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S235248472100456X |
| _version_ | 1819099229110403072 |
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| author | Xiangyu Zhu Xuewei Liu |
| author_facet | Xiangyu Zhu Xuewei Liu |
| author_sort | Xiangyu Zhu |
| collection | DOAJ |
| description | The accurate morphology identification of gas hydrate-bearing sediments (GHBS) has great significance in practical exploitation and subsequent resource evaluation. Previous studies have disclosed two main morphologies for gas hydrate in sediments: pore- and fracture-filling. However, the existing identification methods of gas hydrate’s morphology rarely consider their intrinsic differences in distribution characteristics. In this paper, a new method is proposed to identify the morphology of hydrate according to the scattered distribution of fracture dips for fracture-filling GHBS. Firstly, numerical simulations are performed to study the relationships between the morphology of hydrate and the sonic velocities. Considering the dip variation is within a certain range for fracture-filling hydrate, the theoretical curves show that the resulting mutation degrees between P- and S-wave velocities are inconsistent in fracture-filling GHBS, which is different from pore-filling GHBS. Then the modified estimation method for pointwise Lipschitz exponent α is introduced to capture their differences. The cross plots of Lipschitz exponent for P-wave velocity, α(Vp), and Lipschitz exponent for S-wave velocity, α(Vs), indicate that most of the dots representing pore-filling GHBS are evenly distributed near the line α(Vp)=α(Vs), while the dots representing fracture-filling GHBS are scattered outside the line α(Vp)=α(Vs). Based on these characteristics, a ratio method is put forward to differentiate the two types of hydrate. These hypotheses and methods are verified using the measured P- and S-wave velocities log data at different sites in Leg 204, Ocean Drilling Program (ODP), in the United States. Finally, the results of this new method agree closely with core data. |
| first_indexed | 2024-12-22T00:43:33Z |
| format | Article |
| id | doaj.art-2d8c4106dd76459397416a40bc008179 |
| institution | Directory Open Access Journal |
| issn | 2352-4847 |
| language | English |
| last_indexed | 2024-12-22T00:43:33Z |
| publishDate | 2021-11-01 |
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| series | Energy Reports |
| spelling | doaj.art-2d8c4106dd76459397416a40bc0081792022-12-21T18:44:37ZengElsevierEnergy Reports2352-48472021-11-01780628074Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocityXiangyu Zhu0Xuewei Liu1China University of Geosciences (Beijing), School of Geophysics and Information Technology, No. 29 Xueyuan Street, Haidian District, Beijing 100083, People’s Republic of ChinaCorresponding author.; China University of Geosciences (Beijing), School of Geophysics and Information Technology, No. 29 Xueyuan Street, Haidian District, Beijing 100083, People’s Republic of ChinaThe accurate morphology identification of gas hydrate-bearing sediments (GHBS) has great significance in practical exploitation and subsequent resource evaluation. Previous studies have disclosed two main morphologies for gas hydrate in sediments: pore- and fracture-filling. However, the existing identification methods of gas hydrate’s morphology rarely consider their intrinsic differences in distribution characteristics. In this paper, a new method is proposed to identify the morphology of hydrate according to the scattered distribution of fracture dips for fracture-filling GHBS. Firstly, numerical simulations are performed to study the relationships between the morphology of hydrate and the sonic velocities. Considering the dip variation is within a certain range for fracture-filling hydrate, the theoretical curves show that the resulting mutation degrees between P- and S-wave velocities are inconsistent in fracture-filling GHBS, which is different from pore-filling GHBS. Then the modified estimation method for pointwise Lipschitz exponent α is introduced to capture their differences. The cross plots of Lipschitz exponent for P-wave velocity, α(Vp), and Lipschitz exponent for S-wave velocity, α(Vs), indicate that most of the dots representing pore-filling GHBS are evenly distributed near the line α(Vp)=α(Vs), while the dots representing fracture-filling GHBS are scattered outside the line α(Vp)=α(Vs). Based on these characteristics, a ratio method is put forward to differentiate the two types of hydrate. These hypotheses and methods are verified using the measured P- and S-wave velocities log data at different sites in Leg 204, Ocean Drilling Program (ODP), in the United States. Finally, the results of this new method agree closely with core data.http://www.sciencedirect.com/science/article/pii/S235248472100456XGas hydrateMorphologyP-wave velocityS-wave velocityLipschitz exponent |
| spellingShingle | Xiangyu Zhu Xuewei Liu Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocity Energy Reports Gas hydrate Morphology P-wave velocity S-wave velocity Lipschitz exponent |
| title | Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocity |
| title_full | Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocity |
| title_fullStr | Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocity |
| title_full_unstemmed | Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocity |
| title_short | Morphology identification of gas hydrate from pointwise Lipschitz regularity for P- and S-wave velocity |
| title_sort | morphology identification of gas hydrate from pointwise lipschitz regularity for p and s wave velocity |
| topic | Gas hydrate Morphology P-wave velocity S-wave velocity Lipschitz exponent |
| url | http://www.sciencedirect.com/science/article/pii/S235248472100456X |
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