Geophysical Signature of the Shallow Water Flow in the Deepwater Basin of the Northern South China Sea
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Shallow water flow (SWF), a disastrous geohazard in the continental margin, has threatened deepwater drilling operations. Under overpressure conditions, continual flow delivering unconsolidated sands upward in the shallow layer below the seafloor may cause large and long-lasting uncontrolled flows; these flows may lead to control problems and cause well damage and foundation failure. Eruptions from over-pressured sands may result in seafloor craters, mounds, and cracks. Detailed studies of 2D/3D seismic data from a slope basin of the South China Sea (SCS) indicated the potential presence of SWF. It is commonly characterized by lower elastic impedance, a higher Vp/Vs ratio, and a higher Poisson’s ratio than that for the surrounding sediments. Analysis of geological data indicated the SWF zone originated from a deepwater channel system with gas bearing over-pressured fluid flow and a high sedimentation rate. We proposed a fluid flow model for SWF that clearly identifies its stress and pressure changes. The rupture of previous SWF zones caused the fluid flow that occurred in the Baiyun Sag of the northern SCS.
Key wordsshallow water flow pressure prediction geohazard deepwater hydrocarbons South China Sea
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This work was supported by the National Natural Science Foundation of China (No. 41306037), the China Geological Survey Project (No. DD20160213), and the Strategic Research Center of Oil and Gas Resources Project (No. 2017YQZYPJ0138). We are grateful to the anonymous reviewers for their insightful reviews.
- Dutta, N. C., and Ray, A., 1997. Image of geopressured rocks using velocity and acoustic impedance inversion of seismic data. SEG Annual Meeting, Dallas, Texas, 1929.Google Scholar
- Gong, Z. S., Li, S. T., and Xie, T., 1997. Continental Margin Basin Analysis and Hydrocarbon Accumulation in the Northern South China Sea. Science Press, Beijing, 193–256.Google Scholar
- He, M., Zhu, M., Wang, R. L., Lian, S. Y., and Wu, X. J., 2007. The discussion of time-depth conversion methods in the Baiyun deepwater routgh seafloor area. Progress in Geophysics, 22 (3): 966–971 (in Chinese with English abstract).Google Scholar
- Kok, R. D., Dutta, N., Khan, M., and Mallick, S., 2001. Deepwater geohazard analysis using prestack inversion. SEG Annual Meeting, San Antonio, USA, 0613.Google Scholar
- Lv, S. M., 2003. Seismic characteristic of two deep-water drilling hazards: Shallow-water flow sands and gas hydrate. PhD thesis. University of Texas, Dallas.Google Scholar
- McConnell, D. R., 2000. Optimizing deepwater well locations to reduce the risk of shallow water flow using high resolution 2D and 3D seismic data. Proceedings of Offshore Technology Conference, Houston, Texas, OTC11973.Google Scholar
- Mukerji, T., Dutta, N., Prasad, M., and Dvorkin, J., 2002. Seismic detection and estimation of overpressures Part I: The rock physics basis. CSEG Recorder, 27 (7): 34–57.Google Scholar
- Pang, X., Chen, C. M., Wu, M. S., He, M., and Wu, X. J., 2006. The Pearl River deep-water fan systems and significant geological events. Advances in Earth Science, 21 (8): 793–799.Google Scholar
- Peng, D. J., Pang, X., Chen, C. M., Zhu, M., Huang, X. L., and Shu, Y., 2006. The characteristics and controlling factors for the formation of deep-water fan system in South China Sea. Acta Sedimentologica Sinica, 24 (1): 10–18 (in Chinese with English abstract).Google Scholar
- Qin, G. Q., 2002. Late Cenozoic sequence stratigraphy and sealevel changes in Pearl River Mouth Basin, South China Sea. China Offshore Oil and Gas (Geology), 16 (1): 1–10 (in Chinese with English abstract).Google Scholar
- Rocha, L. S., Junqueira, P., and Roque, J., 2003. Overcoming deep and ultra deepwater drilling challenges. Offshore Technology Conference, Houston, Texas, 1–12.Google Scholar
- Sun, Z., Pang, X., Zhong, Z. H., Zhou, D., Chen, C. M., Hao, H. J., Huang, C. J., and Xu, H. H., 2005. Dynamics of tertiary tectonic evolution of the Baiyun Sag in the Pearl River Mouth Basin. Earth Science Frontiers, 12 (4): 489–498 (in Chinese with English abstract).Google Scholar
- Zhang, G. C., Mi, L. J., Wu, S. G., Tao, W. X., He, S. B., and Lv, J. J., 2007. Deepwater area–The new prospecting targets of northern continental margin of South China Sea. Acta Petrolei Sinica, 28 (2): 15–21 (in Chinese with English abstract).Google Scholar
- Zhou, W., Wang, Y. M., Gao, X. Z., Zhu, W. L., Xu, Q., Xu, S., Cao, J. Z., and Wu, J., 2015. Architecture, evolution history and controlling factors of the Baiyun submarine canyon system from the middle Miocene to Quaternary in the Pearl River Mouth Basin, northern South China Sea. Marine and Petroleum Geology, 67: 389–407.CrossRefGoogle Scholar