Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China Sea
ABSTRACT: Drilling results suggest that the thickness of natural gas hydrates (NGHs) in the Shenhu Area, South China Sea (SCS) are spatially heterogenous, making it difficult to accurately assess the NGHs resources in this area. In the case that free gas exists beneath hydrate deposits, the frequenc...
Main Authors: | , , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
KeAi Communications Co., Ltd.
2022-04-01
|
Series: | China Geology |
Subjects: | |
Online Access: | http://www.sciencedirect.com/science/article/pii/S209651922200115X |
_version_ | 1828040568796610560 |
---|---|
author | Shu-yu Wu Jun Liu Hua-ning Xu Chang-ling Liu Fu-long Ning Hong-xian Chu Hao-ran Wu Kai Wang |
author_facet | Shu-yu Wu Jun Liu Hua-ning Xu Chang-ling Liu Fu-long Ning Hong-xian Chu Hao-ran Wu Kai Wang |
author_sort | Shu-yu Wu |
collection | DOAJ |
description | ABSTRACT: Drilling results suggest that the thickness of natural gas hydrates (NGHs) in the Shenhu Area, South China Sea (SCS) are spatially heterogenous, making it difficult to accurately assess the NGHs resources in this area. In the case that free gas exists beneath hydrate deposits, the frequency of the hydrate deposits will be noticeably attenuated, with the attenuation degree mainly affected by pore development and free gas content. Therefore, the frequency can be used as an important attribute to identify hydrate reservoirs. Based on the time-frequency characteristics of deposits, this study predicted the spatial distribution of hydrates in this area using the frequency division inversion method as follows. Firstly, the support vector machine (SVM) method was employed to study the amplitude versus frequency (AVF) response based on seismic and well logging data. Afterward, the AVF response was introduced as independent information to establish the nonlinear relationship between logging data and seismic waveform. Then, the full frequency band information of the seismic data was fully utilized to obtain the results of frequency division inversion. The inversion results can effectively broaden the frequency band, reflect the NGHs distribution, and reveal the NGHs reservoirs of two types, namely the fluid migration pathway type and the in situ self-generation self-storage diffusion type. Moreover, the inversion results well coincide with the drilling results. Therefore, it is feasible to use the frequency division inversion to predict the spatial distribution of heterogeneous NGHs reservoirs, which facilitates the optimization of favorable drilling targets and is crucial to the resource potential assessment of NGHs.©2022 China Geology Editorial Office. |
first_indexed | 2024-04-10T16:57:35Z |
format | Article |
id | doaj.art-96ced0218b8842a6a13c447a34d0661f |
institution | Directory Open Access Journal |
issn | 2096-5192 |
language | English |
last_indexed | 2024-04-10T16:57:35Z |
publishDate | 2022-04-01 |
publisher | KeAi Communications Co., Ltd. |
record_format | Article |
series | China Geology |
spelling | doaj.art-96ced0218b8842a6a13c447a34d0661f2023-02-07T04:22:53ZengKeAi Communications Co., Ltd.China Geology2096-51922022-04-0152251266Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China SeaShu-yu Wu0Jun Liu1Hua-ning Xu2Chang-ling Liu3Fu-long Ning4Hong-xian Chu5Hao-ran Wu6Kai Wang7School of Engineering, China University of Geosciences, Wuhan 430074, China; Yantai Coastal Zone Geological Survey Center, China Geological Survey, Yantai 264001, China; Chinese Academy of Geological Sciences, Beijing 100037, China; Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China; First author: E-mail address: hnwushuyu@163.com (Shu-yu Wu).Yantai Coastal Zone Geological Survey Center, China Geological Survey, Yantai 264001, China; Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China; Corresponding author: E-mail address: vnlj@163.com (Jun Liu).Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China; The Key Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266071, ChinaLaboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China; The Key Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266071, ChinaSchool of Engineering, China University of Geosciences, Wuhan 430074, ChinaYantai Coastal Zone Geological Survey Center, China Geological Survey, Yantai 264001, ChinaYantai Coastal Zone Geological Survey Center, China Geological Survey, Yantai 264001, ChinaYantai Coastal Zone Geological Survey Center, China Geological Survey, Yantai 264001, ChinaABSTRACT: Drilling results suggest that the thickness of natural gas hydrates (NGHs) in the Shenhu Area, South China Sea (SCS) are spatially heterogenous, making it difficult to accurately assess the NGHs resources in this area. In the case that free gas exists beneath hydrate deposits, the frequency of the hydrate deposits will be noticeably attenuated, with the attenuation degree mainly affected by pore development and free gas content. Therefore, the frequency can be used as an important attribute to identify hydrate reservoirs. Based on the time-frequency characteristics of deposits, this study predicted the spatial distribution of hydrates in this area using the frequency division inversion method as follows. Firstly, the support vector machine (SVM) method was employed to study the amplitude versus frequency (AVF) response based on seismic and well logging data. Afterward, the AVF response was introduced as independent information to establish the nonlinear relationship between logging data and seismic waveform. Then, the full frequency band information of the seismic data was fully utilized to obtain the results of frequency division inversion. The inversion results can effectively broaden the frequency band, reflect the NGHs distribution, and reveal the NGHs reservoirs of two types, namely the fluid migration pathway type and the in situ self-generation self-storage diffusion type. Moreover, the inversion results well coincide with the drilling results. Therefore, it is feasible to use the frequency division inversion to predict the spatial distribution of heterogeneous NGHs reservoirs, which facilitates the optimization of favorable drilling targets and is crucial to the resource potential assessment of NGHs.©2022 China Geology Editorial Office.http://www.sciencedirect.com/science/article/pii/S209651922200115XGas hydratesHeterogeneityFrequency division inversionSelf-generation and self-storage diffusion typeNGHs exploration trial engineeringOil and gas exploration engineering |
spellingShingle | Shu-yu Wu Jun Liu Hua-ning Xu Chang-ling Liu Fu-long Ning Hong-xian Chu Hao-ran Wu Kai Wang Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China Sea China Geology Gas hydrates Heterogeneity Frequency division inversion Self-generation and self-storage diffusion type NGHs exploration trial engineering Oil and gas exploration engineering |
title | Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China Sea |
title_full | Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China Sea |
title_fullStr | Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China Sea |
title_full_unstemmed | Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China Sea |
title_short | Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area, South China Sea |
title_sort | application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the shenhu area south china sea |
topic | Gas hydrates Heterogeneity Frequency division inversion Self-generation and self-storage diffusion type NGHs exploration trial engineering Oil and gas exploration engineering |
url | http://www.sciencedirect.com/science/article/pii/S209651922200115X |
work_keys_str_mv | AT shuyuwu applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea AT junliu applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea AT huaningxu applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea AT changlingliu applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea AT fulongning applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea AT hongxianchu applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea AT haoranwu applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea AT kaiwang applicationoffrequencydivisioninversioninthepredictionofheterogeneousnaturalgashydratesreservoirsintheshenhuareasouthchinasea |