ESTIMATION OF GAS HYDRATE SATURATION WITH MODIFIED BIOT-GASSMANN THEORY: A CASE FROM NORTHERN SOUTH CHINA SEA

GAO Hongyan; ZHONG Guangfa; LIANG Jinqiang; GUO Yiqun

doi:10.3724/SP.J.1140.2012.04083

2012 Vol. 32, No. 4

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Article navigation > Marine Geology & Quaternary Geology > 2012 > 32(4): 83-89

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GAO Hongyan, ZHONG Guangfa, LIANG Jinqiang, GUO Yiqun. ESTIMATION OF GAS HYDRATE SATURATION WITH MODIFIED BIOT-GASSMANN THEORY: A CASE FROM NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2012, 32(4): 83-89. doi: 10.3724/SP.J.1140.2012.04083

Citation:

GAO Hongyan, ZHONG Guangfa, LIANG Jinqiang, GUO Yiqun. ESTIMATION OF GAS HYDRATE SATURATION WITH MODIFIED BIOT-GASSMANN THEORY: A CASE FROM NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2012, 32(4): 83-89. doi: 10.3724/SP.J.1140.2012.04083

ESTIMATION OF GAS HYDRATE SATURATION WITH MODIFIED BIOT-GASSMANN THEORY: A CASE FROM NORTHERN SOUTH CHINA SEA

1 State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China;
2 Guangzhou Marine Geological Survey, Guangzhou 510760, China

Received Date: 06 July 2012

Revised Date: 17 July 2012

Abstract

Abstract

The modified Biot-Gassmann theory (BGTL) proposed by Lee (2002) is applied in this study to estimation of the saturation of gas hydroate in the deep-water unconsolidated clayey sediments from the Well A, Shenhu area, northern South China Sea. The BGTL theory assumes that the ratio of the shear to compressional velocities of an unconsolidated sediment is related to the ratio of the shear to compressional velocities of the solid matrix in the sediment and its porosity. Parameters involved in the model are related to the occurrence of gas hydrate, mineral components,pressure differentiation,porosity,and pore structure of the sediments. The cross plot of velocity from sonic logging vs. concentration of gas hydrate from core measurements suggest that the occurrence of gas hydrate in the sediments of Well A is more or less close to the matrix model. Statistics from core smear slide data suggest that the sediment matrix in well A can be simplified as three major mineral components, i.e clay, carbonate, and terrigenous clastic minerals. The elastic modulus and density values of the matrix are calculated by the elastic modulus and density values of the individual mineral components and their volume percentage. As estimated, the gas hydrate in Well A is mainly distributed in the depth interval of 195 to 220 meters below sea floor with a highest concentration of gas hydrate up to 47%, which matches well with the results from core measurements.
- modified Biot-Gassmann model /
- P-vave velocity /
- deep-water unconsolidated clayey sediments /
- saturation of gas hydrate /
- Shenhu area, northern South China Sea

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References

[1]	陆敬安,梁金强,罗文造. 径向基函数神经网络在计算天然气水合物饱和度中的应用研究[J]. 海洋通报, 2009, 28(4):102-106. Google Scholar [LU Jingan,LIANG Jinqiang,LUO Wenzao. The study on the application of radial basis networks to saturation evaluation of gas hydrate[J]. Marine Sciencce Bulletin, 2009, 28(4):102-106.] Google Scholar
[2]	王祝文, 李舟波, 刘菁华. 天然气水合物的测井识别和评价[J]. 海洋地质与第四纪地质, 2003, 23(2):97-102. Google Scholar [WANG Zhuwen, LI Zhoubo,LIU Jinghua. Logging identification and evaluation methods for gas hydrate[J]. Marine Geology and Quaternary Geology, 2003, 23(2):97-102.] Google Scholar
[3]	郭依群,乔少华,吕万军. 基于声波速度分析神狐海域水合物垂向分布特征[J]. 海洋地质前沿, 2011,27(7):7-10. Google Scholar [GUO Yiqun, QIAO Shaohua, LÜ Wanjun. Vertical distribution of gas hydrate in Shenhu area of the South China based on acoustic velocity[J]. Marine Geology Frontiers, 2011,27(7):7-10.] Google Scholar
[4]	范宜仁, 朱学娟. 天然气水合物储层测井响应与评价方法综述[J]. 测井技术, 2011, 35(2):104-111. Google Scholar [FAN Yiren, ZHU Xuejuan. Review on logging responses and evaluation methods of natural gas hydrated reservoir[J]. Well Logging Technology, 2011, 35(2):104-111.] Google Scholar
[5]	郭星旺, 祝有海. 永久冻土区天然气水合物饱和度评价技术[J]. 海洋地质前沿, 2011, 27(5):59-66. Google Scholar [GUO Xingwang,ZHU Youhai. Saturation evaluation of gas hydrate in permafrost sediments[J]. Marine Geology Frontiers, 2011, 27(5):59-66.] Google Scholar
[6]	Stoll R D, Ewing J, Bryan G M. Anomalous wave velocities in sediments containing gas hydrates[J]. Geophysial Research, 1971, 76(8):2090-2094. Google Scholar
[7]	Shankar U, Riedel M. Gas hydrate saturation in the Krishna-Godavari basin from P-wave velocity and electrical resistivity logs[J]. Marine and Petroleum Geology, 2011, 28(10):1768-7778. Google Scholar
[8]	Helgerud M B, Dvorkin J, Nur A. Elastic-wave velocity in marine sediments with gas hydrates:Effective medium modeling[J]. Geophysical Research Letters, 1999, 26(13):2021-2024. Google Scholar
[9]	Zimmerman R W, King M S. The effect of the extent of freezing on seismic velocities in unconsolidated permafrost[J]. Geophysics, 1986, 51(6):1285-1290. Google Scholar
[10]	Lee M W. Modified Biot-Gassmann Theory for calculating elastic velocities for unconsolidated and consolidated sediments[J]. Marine Geophysical Researches, 2002, 23:403-412. Google Scholar
[11]	Lee M W. Biot Gassmann theory for velocities of gas hydrate-bearing sediments[J]. Geophysics, 2002, 67(6):17111719. Google Scholar
[12]	梁劲, 王明君, 王宏斌,等. 南海神狐海域天然气水合物声波测井速度与饱和度关系分析[J]. 现代地质, 2009, 23(2):217-222. Google Scholar [LIANG Jin,WANG Mingjun,WANG Hongbin,et al. Relationship between the sonic logging velocity and saturation of gas hydrate in Shenhu Area,Northern Slope of South China Sea[J]. Geoscience, 2009, 23(2):217-222.] Google Scholar
[13]	陆敬安, 杨胜雄, 吴能友, 等. 南海神狐海域天然气水合物地球物理测井评价[J]. 现代地质, 2008, 22(3):447-451. Google Scholar [LU Jingan,YANG Shengxiong,WU Nengyou,et al. Well logging evaluation of gas hydrates in Shenhu area,South China Sea[J]. Geoscience, 2008, 22(3):447-451.] Google Scholar
[14]	王秀娟, 吴时国, 刘学伟, 等. 基于电阻率测井的天然气水合物饱和度估算及估算精度分析[J]. 现代地质, 2010, 24(5):993-999. Google Scholar [WANG Xiujuan,WU Shiguo,LIU Xuewei,et al. Estimation of gas hydrate saturation based on resistivity logging and analysis of estimation error[J]. Geoscience, 2010, 24(5):993-999.] Google Scholar
[15]	Biot M A. General theory of three-dimensional consolidation[J]. Journal of Applied Physics, 1941, 12(2):155-164. Google Scholar
[16]	Garat J, Krief M, Stellingwerff J, et al. A petrophysical interpretation using the velocities of P and S waves (Full-waveform sonic)[J]. Society of Petrophysicists and Well-Log Analyst, 1990, 31(6):355-369. Google Scholar
[17]	Prasad M. Acoustic measurements in unconsolidated sands at low effective pressure and overpressure detection[J]. Geophysics, 2002, 67(2):405-412. Google Scholar
[18]	Reuss A.Berechnung der fliessgrenze von mischkristallen auf grund der Plastizi-tatsbedingungen für einkristalle[J].Zeitschrift für Angewandte matic aus Mechanik, 1929, 9:49-58. Google Scholar
[19]	Voigt W. Lehrbunch der Kirstallphysik[M].Teubner,Leipzig, 1928. Google Scholar
[20]	Hill R. The elastic behavior of a crys-tallin eaggregate[J].Proceedings of the Physical Society, 1952, A65(5):349-354. Google Scholar
[21]	汪鹏, 钟广法. 南海ODP1144站深海沉积牵引体的岩石物理模型研究[J]. 地球科学进展, 2012, 27(3):359-366. Google Scholar [WANG Peng, ZHONG Guangfa. Application of rock physics model to the deep-sea sediment drift at ODP site 1144, Northern South China Sea[J]. Advances In Earth Science, 2012, 27(3):359-366.] Google Scholar
[22]	Dai J, Snyder F,Gillespie D, et al. Exploration for gas hydrates in the deepwater, northern Gulf of Mexico:Part Ⅰ. A seismic approach based on geologic model, inversion, and rock physics principles[J]. Marine and Petroleum Geology. 2008, 25(9):830-844. Google Scholar
[23]	Dai J, Xu H, Snyder F, et al. Detection and estimation of gas hydrates using rock physics and seismic inversion:examples from the northern deepwater Gulf of Mexico[J]. The Leading Edge, 2004, 23(1):60-66. Google Scholar
[24]	Dvorkin J, Nur A, Uden R, et al. Rock physics of a gas hydrate reservoirs[J]. The Leading Edge, 2003, 22(9):842-847. Google Scholar
[25]	Ecker C, Dvorkin J, Nur A. Sediments with gas hydrates:internal structure from seismic AVO[J]. Geophysics, 1998, 63, 1659-1669. Google Scholar
[26]	Xu H,Dai J, Snyder F, et al. Seismic Detection and Quantification of Gas Hydrates Using Rock Physics and Inversion[M].Advances in Gas Hydrates Research, Kluwer, New York, 2004. Google Scholar
[27]	Yun T S, Francisca F M, Santamarina J C, et al. Compressional and shear wave velocities in uncemented sediment containing gas hydrate[J]. Geophysical Research Letters, 2005, 32, L10609, doi:10.1029/2005GL022607. Google Scholar
[28]	钟广法, 李前裕, 陈强,等. 测井资料反演南海北部陆坡渐新统的矿物组分[J]. 同济大学学报:自然科学版, 2006, 34(10):1403-1407. Google Scholar [ZHONG Guangfa, LI Qianyu, CHEN Qiang, et al.Oligocene mineral component inversion based on geophysical well logs from ODP hole 1148A,South China Sea[J]. Journal of Tongji University (Natural Science), 2006, 34(10):1403-1407.] Google Scholar
[29]	Wang Z, Wang H, Cates M E. Effective elastic properties of solid clays[J]. Geophysics, 2001, 66(2):428-440. Google Scholar