GAS HYDRATE SATURATION AND ITS RELATION WITH GRAIN SIZE OF THE HYDRATE-BEARING SEDIMENTS IN THE SHENHU AREA OF NORTHERN SOUTH CHINA SEA
-
摘要: 为探讨沉积物粒度与水合物饱和度的关系,对南海神狐海域水合物钻探区2个获取水合物的钻孔岩心沉积物进行了粒度分析及粒度与水合物饱和度对比分析。结果表明,含水合物沉积物具有粉砂含量72%~82%、黏土含量小于30%、砂含量一般小于10%的基本特征,其中粉砂中以8~32和32~63 μm粒级的中细-粗粉砂占优势;该特征与上下不含水合物层位粒度特征没有明显的差异;含水合物层砂、粗粉砂含量高的层位与水合物饱和度高的层位呈良好的对应关系,粗粒沉积物更有利于孔隙的发育和水合物的形成。Abstract: Grain sizes are analyzed for the sediments taken from two drill holes in the Shenhu area of northern South China Sea in order to understand the relationship between the saturations of gas hydrates and the grain-size of the sediments. Results suggest that the silt fraction is the dominant component of gas-hydrate-bearing sediments in the studied area, making up about 72%~82% of the sedimentary grains. The second component is clay, which is usually less than 30%; whereas the sand fraction is less than 10%. The Grain size distribution pattern of the gas-hydrate-bearing sediments is similar to the non-gas-hydrate-bearing sediments above and below. Coarse silt(0.063~0.032 mm) and sand(0.063~0.5 mm) are usually high in gas hydrates saturations, further suggesting that coarse sediments are more favorable for the formation of gas hydrates.
-
Key words:
- sedimentary grain size /
- gas-hydrate-bearing Sediments /
- Shenhu Area /
- South China Sea
-
-
[1] Ginsburg G, Soloviev V, Matveeva T,et al. Sediment grain-size control on hydrate presence, sites 994, 995 and 997.[C]//PaullC K, MatsumotorR, Wallace P J, eds. Proceeding of ODP Initial Reports 164. College Station TX:Ocean Drilling Program, 2000:237-245.
[2] Shipboard Scientific Party. Leg 204 summary[C]//TR HUA M, BOHRMANN G, RACK F R, et al.Proc ODP Init Repts204. College Station TX:Ocean DrillingProgram,2003:1-75.
[3] KraemerLM, Owen R M, Dickens G R. Lithology of the upper gas hydrate zone, Blake outer ridge, a link between diatoms, porosity, and gas hydrate[C]//Paull C K, Matsumotor R, Wallace P J, eds. Proceeding of ODP Initial Reports 164. College Station TX:Ocean Drilling Program, 2000:229-236.
[4] 苏新,宋成兵,方念乔.东太平洋水合物海岭BSR以上沉积物粒度变化与气体水合物分布[J].地学前缘,2005,12(1):234-242.
[SU Xin, SONG Chengbing, FANG Nianqiao. Variation in grain size of sediments above BSR and correlation with the occurrence of gas hydrates on Hydrates Ridge, East Pacific[J].Earth Science Frontiers,2005,12(1):234-242.]
[5] 王家生,高钰涯,李清,等.沉积物粒度对水合物形成的制约:来自IODP航次证据[J].地球科学进展,2007,22(7):659-665.
[WANG Jiasheng, GAO Yuya, LI Qing,et al. Grain size constraint on gas hydrate occurrence:evidence from sediment size during IODP 311[J]. Advances in Earth Science,2007,22(7):659-665.]
[6] 陈芳,苏新,周洋,等.南海北部陆坡神狐海域晚中新世以来沉积物中生物组分变化特征及意义[J].海洋地质与第四纪地质,2009, 29(2):1-8.
[CHEN Fang,SU Xin,ZHOU Yang, et al. Variations in biogenic components of Late Miocene-Holocene sediments from Shenhu Area in the Northern South China Sea and their geological implications[J]. Marine Geology and Quaternary Geology, 2009,29(2):1-8.]
[7] Archie G E. The electrical resistivity log as an aid in determining some reservoir characteristics[J].American Insititute of Mining, Metallurgica and Petroleum Engineers, 1942, 146:54-67.
[8] CollettT S. Well log evaluation of gas hydrate saturations[C]//SPWLA 39th Annual Logging Symposium. Houston (SPWLA), 1998.
[9] CollettT S, Ladd J. Detection of gas hydrate with downhole logs and assessment of gas hydrate concentrations (saturations) and gas volumes on the Blake Ridge with electrical resistivity log data[C]//Paull C K, Matsumoto R, Wallace P J, eds. Proceeding of ODP, Science Results, 164. College Station, TX (Ocean Drilling Program). 2000:179-191.
[10] Tréhu AM, Long P E, Torres M,et al. Three-dimensional distribution of gas hydrate beneath Southern Hydrate Ridge:Constraints from ODP Leg 204[J].Earth Planet Science Letters,2004, 222:845-862.
-
计量
- 文章访问数: 1424
- PDF下载数: 4
- 施引文献: 0
下载: