Citation: | Zaisheng Gong, Jiaming Yang, Jianwu Hu, Fang Hao. Development of Diapirs and Accumulation of Natural Gases in Yinggehai Basin. Journal of Earth Science, 2001, 12(2): 127-131. |
Overpressure developed throughout most of the Yinggehai basin. The burial depth to top overpressure varied from about 1 600 m to 4 500 m, with the shallowest top overpressure occurring in the depocenter. The main cause of the overpressure was disequilibrium compaction resulting from rapid sedimentation of fine-grained sediments. The overpressure was strengthened by the retention of fluids including gases due to lack of faults before diapir development. The diapirism in the Yinggehai basin was a combined result of the strong overpressure and the tensile stress field caused by the right-lateral slip of the boundary-fault. The diapirism, a product of the movement of overpressured fluids and plastic shales, shaped the vertical conduits from source to traps that would be absent without overpressured fluid release. Natural gas accumulation in traps in the diapir structure zones was also intermittent, which can be inferred from the inter-reservoir compositional heterogeneity, transient thermal effect of fluid flow and migration fractionation.
Curiale J A, Bromley B W, 1996. Migration Induced Compositional Changes in Oils and Condensates of a Single Field. Organic Geochemistry, 24: 1097-1113 doi: 10.1016/S0146-6380(96)00099-X |
Gong Z, Li S, 1997. Continental Margin Basin Analysis and Hydrocarbon Accumulation of the Northern South China Sea. Beijing: Science Press. 510 (in Chinese) |
Hao F, Li S, Dong W, et al, 1998. Abnormal Organic Matter Maturation in the Yinggehai Basin, Offshore South China Sea: Implications for Hydrocarbon Expulsion and Fluid Migration from Overpressured Systems. Journal of Petroleum Geology, 21: 427-444 doi: 10.1111/j.1747-5457.1998.tb00794.x |
Holm G M, 1998. Distribution and Origin of Overpressure in the Central Graben of the North Sea. In: Law B E, Ulmishek G F, Slavin V I, eds. Abnormal Pressure in Hydrocarbon Environments. AAPG Memoir 70, 123-144 |
Hunt J M, 1990. Generation and Migration of Petroleum from Abnormally Pressured Fluid Compartments. AAPG Bulletin, 75: 328-330 |
Hunt J M, 1996. Petroleum Geology and Geochemistry. 2nd ed. San Francisco: Freeman and Company. 743 |
Law B E, Spencer C W, 1998. Abnormal Pressure in Hydrocarbon Environments. In: Law B E, Ulmishek G F, Slavin V I, eds. Abnormal Pressure in Hydrocarbon Environments. AAPG Memoir 70, 1-11 |
Ortoleva P J, 1994. Basin Compartmentation: Definitions and Mechanisms. In: Ortoleva P J, ed. Pressure Compartments and Seas. AAPG Memoir 61, 39-51 |
Price L C, 1994. Basin Richness and Source Rock Disruption: A Fundamental Relationship? Journal of Petroleum Geology, 17: 5-38 doi: 10.1111/j.1747-5457.1994.tb00112.x |
Roberts S J, Nunn J A, 1995. Episodic Fluid Expulsion from Geopressured Sediments. Marine and Petroleum Geology, 12 (2) : 195-204 doi: 10.1016/0264-8172(95)92839-O |
Swarbrick R E, Osborne M J, 1998. Mechanisms That Generate Abnormal Pressures: An Overview. In: Law B E, Ulmishek G F, Slavin V I, eds. Abnormal Pressure in Hydrocarbon Environments. AAPG Memoir 70, 13-34 |
Thompson K F M, 1987. Fractionated Aromatic Petroleums and the Generation of Gas-Condensates. Organic Geochemistry, 11: 573-590 doi: 10.1016/0146-6380(87)90011-8 |
Thompson K F M, 1988. Gas-Condensate Migration and Oil Fractionation in Deltaic Systems. Marine and Petroleum Geology, 5: 237-246 doi: 10.1016/0264-8172(88)90004-9 |
Whelan J K, Kennicutt Ⅱ M C, Brooks J M, et al, 1994. Organic Geochemical Indicators of Dynamic Fluid Flow Process in Petroleum Basins. Organic Geochemistry, 22: 587-615 doi: 10.1016/0146-6380(94)90127-9 |