李彦龙, 陈强, 胡高伟, 马廷雷, 吴能友, 刘昌岭. 神狐海域W18/19区块水合物上覆层水平渗透系数分布[J]. 海洋地质与第四纪地质, 2019, 39(2): 157-163. DOI: 10.16562/j.cnki.0256-1492.2017080103
引用本文: 李彦龙, 陈强, 胡高伟, 马廷雷, 吴能友, 刘昌岭. 神狐海域W18/19区块水合物上覆层水平渗透系数分布[J]. 海洋地质与第四纪地质, 2019, 39(2): 157-163. DOI: 10.16562/j.cnki.0256-1492.2017080103
LI Yanlong, CHEN Qiang, HU Gaowei, MA Tinglei, WU Nengyou, LIU Changling. Distribution of horizontal permeability coefficient of the cover layer of HBS at Site W18/19 of Shenhu area[J]. Marine Geology & Quaternary Geology, 2019, 39(2): 157-163. DOI: 10.16562/j.cnki.0256-1492.2017080103
Citation: LI Yanlong, CHEN Qiang, HU Gaowei, MA Tinglei, WU Nengyou, LIU Changling. Distribution of horizontal permeability coefficient of the cover layer of HBS at Site W18/19 of Shenhu area[J]. Marine Geology & Quaternary Geology, 2019, 39(2): 157-163. DOI: 10.16562/j.cnki.0256-1492.2017080103

神狐海域W18/19区块水合物上覆层水平渗透系数分布

Distribution of horizontal permeability coefficient of the cover layer of HBS at Site W18/19 of Shenhu area

  • 摘要: 水合物储层上覆地层水平渗透系数是水合物试采工程设计的关键参数之一。以我国南海北部神狐海域W18/19区块水合物上覆钙质黏土层孔压静力触探数据为依托,在剖析基于位错理论的地层水平渗透系数预测模型基本原理的基础上,进行W18/19区块水合物层上覆钙质黏土层水平渗透系数纵向分布规律预测。结果表明,Elsworth方法不适用于W18/19区块水合物层上覆钙质黏土层水平渗透系数评价; W18/19区块水合物层上覆钙质黏土层水平渗透系数为0.1×10-8 ~4×10-8m/s,且随着深度的增大而减小; 30mbsf以浅地层预测结果受扰动较大,30mbsf以深地层的水平渗透率系数为0.1×10-8 ~0.6×10-8m/s,且不同模型预测结果间的差异较小; 孔压扩散模型和初始孔压分布函数的差异是导致不同模型预测结果差异的根本因素。

     

    Abstract: Horizontal permeability coefficient (HPC) of the cover layer of hydrate bearing sediment(HBS) is one of the crucial factors that affect engineering design for marine hydrate production test. Based on the piezocone penetration test (CPTU) data obtained from the calcareous cover layer of hydrate formation at site W18/19 of the Shenhu area, different HPC estimation models based on the dislocation theory were analyzed, together with their corresponding adaptability to calcareous cover clay in the Shenhu area of northern South China Sea. Finally, the vertical distribution of HPC value for the calcareous cover clay of HBS at the site of W18/19 was predicted and analyzed using the above prediction models. The research results show that the Elsworth (2005) method is not adapt for HPC evaluation at site W18/19. Totally, HPC value at site W18/19 ranges from 0.1×10-8~4×10-8m/s and increase gradually with depth. In the interval shallower than 30mbsf, HPC values are vastly fluctuated because of some disturbance. In the interval below 30mbsf, of which the HPC values range from 0.1×10-8~0.6×10-8m/s, however, the gaps from different prediction models come closer. Prediction results indicate that pore-pressure diffusion model and diffusion function are two basic factors that lead to the gaps among HPC values obtained from different models.

     

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